Why the Flow of Time Is an Illusion(nautil.us)
nautil.us
Why the Flow of Time Is an Illusion
http://nautil.us/issue/71/flow/why-the-flow-of-time-is-an-illusion
180 comments
This is true. You also need to take into account how each day is a smaller and smaller percentage of your life which might be why kids think summer vacation lasts forever but it flys by for parents.
This explanation comes up frequently in these discussions. It makes a certain amount of sense on its face, but is there any evidence that this actually affects our perception of time?
See Douwe Draaisma, Why Life Speeds Up as You Get Older, a book that seeks to explain the work done in psychology and neuroscience on this issue to a popular audience.
We don't even know if our brain even has a uniform perception of time (outside of the cultural definition), let alone what that might be. It's all guesswork anyway.
This isn't really evidence at all, but it's well known that as people age, it becomes more difficult to new memories, than it is to keep old ones[1], which is why you regularly get old people mixing up their current loved ones with old, dead people; and why "you can't teach an old dog new tricks".
If the passage of time in the human experiences is largely a function of the memories we make. It's not at all surprising that things seem to go faster as we age.
[1] There's common-sense explaination for this, but I don't think the exact mechanism is understood. It is widely observed though.
If the passage of time in the human experiences is largely a function of the memories we make. It's not at all surprising that things seem to go faster as we age.
[1] There's common-sense explaination for this, but I don't think the exact mechanism is understood. It is widely observed though.
Why would your brain need consciousness to anticipate the future? A computer, which has no consciousness, would be able to do the same.
> A computer, which has no consciousness
[citation needed]
[citation needed]
Right, as would all statements of lack of consciousness in anything. That way lies panpsychism. Which of course is a valid belief.
Even if you believe in panpsychism, there are good reasons to doubt a computer has anything beyond micro-experiences. You can't solve the binding-problem (for example, your left and right visual fields are unified as a coherent whole) with discrete parts.
Consciousness is how the algorithm feels from inside.
Why would we need to 'feel' anything from the inside? We could operate perfectly well as 'machines' without having this 'feeling'. Also, consciousness isn't a feeling. It is what makes it possible at all to have a subjective experience of feelings in the first place. And that is mind-blowing the more you think of it.
How do you know that what you say about consciousness isn’t just a language game you play where you define words in terms of other words that are hardly connected to anything?
“What it is like to be a bat”
“What it is like to experience something”
After having seen descriptions of all the physical components of experience:
“It is Qualia! What it is like to see red”
Having been described all the differences between sensing red and green, and people who can’t tell the difference, and the suggestion that maybe what you call consciousness is the collection of abilities to distinguish various things...
“No, it is something more”.
What is it? How is that different than saying there is a “true essence” of a thing, over and above its properties? This is what greek philosophers asked about.
“It is the sense of identity. Integrating into one experience.”
Ok so what about Theseus’ ship? If all the cells are being replaced? What about your gut brain? Coukd it have a separate consciousness living in the same body?
“These are interesting questions”.
Here is a statement I will make:
If you are careful to define your words unambgiously, in terms of RICH connections to other concepts, you will find that you won’t be able to ask a single question about the following subjects without having a straightforward and simple reductionist-sounding answer:
Morality
Consciousess
Existence
“What it is like to be a bat”
“What it is like to experience something”
After having seen descriptions of all the physical components of experience:
“It is Qualia! What it is like to see red”
Having been described all the differences between sensing red and green, and people who can’t tell the difference, and the suggestion that maybe what you call consciousness is the collection of abilities to distinguish various things...
“No, it is something more”.
What is it? How is that different than saying there is a “true essence” of a thing, over and above its properties? This is what greek philosophers asked about.
“It is the sense of identity. Integrating into one experience.”
Ok so what about Theseus’ ship? If all the cells are being replaced? What about your gut brain? Coukd it have a separate consciousness living in the same body?
“These are interesting questions”.
Here is a statement I will make:
If you are careful to define your words unambgiously, in terms of RICH connections to other concepts, you will find that you won’t be able to ask a single question about the following subjects without having a straightforward and simple reductionist-sounding answer:
Morality
Consciousess
Existence
I'm not really sure what you're arguing here. I would certainly say consciousness is 'something more', and that this something more has to be something non-material (or at least using 'materials' that have wildly different properties than what we observe using the scientific method).
Theseus' ship is a problem for a purely materialistic explanation of consciousness, for, by that account, consciousness should be a function of your material makeup, and yet, it remains constant despite change in both what makes up your cells and the specific configuration of those cells.
As for RICH I don't know what that means.
Theseus' ship is a problem for a purely materialistic explanation of consciousness, for, by that account, consciousness should be a function of your material makeup, and yet, it remains constant despite change in both what makes up your cells and the specific configuration of those cells.
As for RICH I don't know what that means.
Theseus' ship is not a problem for materialistic explanations of anything; it's a problem for anybody who thinks the nature of a thing is governed by the words used to describe it.
The fact that you would continue to call a ship the same after exchanging all its parts is not an ontological problem, it is a problem arising from the imprecise use of language or intention to use an approximate/aggregate notion of identity. (I would recommend studying topology for a more modern understanding of this.)
The fact that you would continue to call a ship the same after exchanging all its parts is not an ontological problem, it is a problem arising from the imprecise use of language or intention to use an approximate/aggregate notion of identity. (I would recommend studying topology for a more modern understanding of this.)
And yet, consciousness is something that remains, regardless of whether we name it as such, and regardless of the specific cells that make up our brains. So it's as if it is the only thing that is not named 'by us' and yet remains 'something' independent of its makeup.
> I would certainly say consciousness is 'something more', and that this something more has to be something non-material (or at least using 'materials' that have wildly different properties than what we observe using the scientific method).
If you're interested in having that idea challenged, I heartily recommend reading "Godel, Escher, Bach" - the book explains how complexity (perhaps to the point of consciousness) can emerge from "simple" systems.
If you're interested in having that idea challenged, I heartily recommend reading "Godel, Escher, Bach" - the book explains how complexity (perhaps to the point of consciousness) can emerge from "simple" systems.
I certainly am interested in this, but I also would like to note that this is not just a matter of something 'more complex' arising and that I lack the imagination necessary to see how something very very complex can arise. Rather, subjective experience is a phenomenon that, no matter how complex your system is, is qualitatively different.
It's not like this is a trivial problem that philosophers of mind have figured out long ago. As someone else mentioned in this thread, it is a very deep problem. If you want to have your view challenged I encourage you to read any introductory book to philosophy of mind.
It's not like this is a trivial problem that philosophers of mind have figured out long ago. As someone else mentioned in this thread, it is a very deep problem. If you want to have your view challenged I encourage you to read any introductory book to philosophy of mind.
I always like having my views challenged :) can you recommend any particular text or would the top hit on amazon be sufficient?
Also, in terms of GEB, the book shows how self-reference leads to a system being able to make statemets about itself, leading to, eventually, something more than (apparently) the sum of their parts. It’s a funky mix of philosophy and math and I think you’d like it.
Also, in terms of GEB, the book shows how self-reference leads to a system being able to make statemets about itself, leading to, eventually, something more than (apparently) the sum of their parts. It’s a funky mix of philosophy and math and I think you’d like it.
https://www.amazon.com/Philosophy-Mind-Short-Introduction/dp...
I'll read GEB :)
I'll read GEB :)
Thank you! I ended up buying Jaworski's Philosophy of Mind: A Comprehensive Introduction before I saw your comment. So far it's interesting stuff! Many thanks for suggesting this topic :)
> Theseus' ship is a problem for a purely materialistic explanation of consciousness,
Theseus's ship is not a problem for materialistic views at all. A function of matter configuration is not the same as a function of matter. In the same way, a wave on water is constantly changing its material makeup, and yet you can still call it "the same wave".
> As for RICH I don't know what that means.
Rich, i.e. non-trivial. That is, no tautologies or something slightly above tautology in the depth of information.
Theseus's ship is not a problem for materialistic views at all. A function of matter configuration is not the same as a function of matter. In the same way, a wave on water is constantly changing its material makeup, and yet you can still call it "the same wave".
> As for RICH I don't know what that means.
Rich, i.e. non-trivial. That is, no tautologies or something slightly above tautology in the depth of information.
Why are you thinking? You are anticipating various scales of "the future", using memories of past events.
As computers try to anticipate the future more, they may also start to "experience" things.
As computers try to anticipate the future more, they may also start to "experience" things.
That's one of the uses of thinking, yes, but it's hardly the only one, unless by some procrustean method you force all my thoughts to 'really' be about the future. In which case I'd say the statement is close to devoid of meaning.
Furthermore, thinking and consciousness is not the same thing.
Furthermore, thinking and consciousness is not the same thing.
I think I based my initial thoughts on this paper (or a citation of):
http://pespmc1.vub.ac.be/Papers/AnticipationControl.pdf
http://pespmc1.vub.ac.be/Papers/AnticipationControl.pdf
Consciousness is the algorithm. What you call "consciousness" is how the computational processes that are you see themselves.
It could work differently, but for some reasons it doesn't, and we don't understand the reasons.
It could work differently, but for some reasons it doesn't, and we don't understand the reasons.
I find kabbalah very interesting, because this assertion has been made for a long time without us having something tangible to compare it to. Now we have computers, basic AI, and no signs of slowing down. What if kabbalah, or something similar, is actually how consciousness emerges across different types of observers? I.e., consciousness is a "most likely" pattern that emerges from the initial ability to conceive of time.
Tarot is an example of a more personified version of the same archetypal phenomenon. The first few cards are indicative of susceptibility to experience, concentration of experience, awareness of experience, multiplicity of experience, and mastery of experience.
Tarot is an example of a more personified version of the same archetypal phenomenon. The first few cards are indicative of susceptibility to experience, concentration of experience, awareness of experience, multiplicity of experience, and mastery of experience.
Well, that's a bold claim, and it doesn't really say anything substantial, in my opinion. What does it mean to see yourself? Are the electrical impulses of your brain somehow registering themselves and then reflecting them to yet another part of the brain which.. does what exactly?
Believing that consciousness can be explained in terms of material processes is certainly a valid belief, but it is just that: a belief. Believing that a certain configuration of atoms, no matter how involved, can give rise to subjective experience is not far from believing in some kind of magic.
And before you retort that a lot of phenomena in nature are 'emergent', I will say:all those phenomena are ultimately explicable in terms of their basic atomic constituents. Consciousness is qualitatively different. You cannot start with the experience of being hungry and then somehow explain the whole process from your stomach being empty to that qualitative experience and how it feels for you.
Believing that consciousness can be explained in terms of material processes is certainly a valid belief, but it is just that: a belief. Believing that a certain configuration of atoms, no matter how involved, can give rise to subjective experience is not far from believing in some kind of magic.
And before you retort that a lot of phenomena in nature are 'emergent', I will say:all those phenomena are ultimately explicable in terms of their basic atomic constituents. Consciousness is qualitatively different. You cannot start with the experience of being hungry and then somehow explain the whole process from your stomach being empty to that qualitative experience and how it feels for you.
> Believing that consciousness can be explained in terms of material processes is certainly a valid belief, but it is just that: a belief.
It's a belief, true, but it's kind of a privileged one, since it's so successful at explaining literally every other thing we observe about the universe. Why brains would be different?
> Believing that a certain configuration of atoms, no matter how involved, can give rise to subjective experience is not far from believing in some kind of magic.
This argument would be stronger 500 years ago, but I don't know how one can consider this "not far from believing in magic" after seeing a computer. Or, after observing brains of different animals - from insects to simians. Or, after discovering circuit-bending and realizing how similar it is to prodding a brain. There's ample evidence against the hypothesis that the human brain is the only magical object in the universe and that it somehow transcends physics.
> And before you retort that a lot of phenomena in nature are 'emergent', I will say:all those phenomena are ultimately explicable in terms of their basic atomic constituents. Consciousness is qualitatively different. You cannot start with the experience of being hungry and then somehow explain the whole process from your stomach being empty to that qualitative experience and how it feels for you.
Why? If I gave you a device that could trace the state of every molecule and charge in my brain to the extent allowed by uncertainty principle, would you still be confident in believing that? Just because we don't have a device like this doesn't mean consciousness is magic.
It's a belief, true, but it's kind of a privileged one, since it's so successful at explaining literally every other thing we observe about the universe. Why brains would be different?
> Believing that a certain configuration of atoms, no matter how involved, can give rise to subjective experience is not far from believing in some kind of magic.
This argument would be stronger 500 years ago, but I don't know how one can consider this "not far from believing in magic" after seeing a computer. Or, after observing brains of different animals - from insects to simians. Or, after discovering circuit-bending and realizing how similar it is to prodding a brain. There's ample evidence against the hypothesis that the human brain is the only magical object in the universe and that it somehow transcends physics.
> And before you retort that a lot of phenomena in nature are 'emergent', I will say:all those phenomena are ultimately explicable in terms of their basic atomic constituents. Consciousness is qualitatively different. You cannot start with the experience of being hungry and then somehow explain the whole process from your stomach being empty to that qualitative experience and how it feels for you.
Why? If I gave you a device that could trace the state of every molecule and charge in my brain to the extent allowed by uncertainty principle, would you still be confident in believing that? Just because we don't have a device like this doesn't mean consciousness is magic.
> It's a belief, true, but it's kind of a privileged one, since it's so successful at explaining literally every other thing we observe about the universe. Why brains would be different?
It's successful at explaining everything that can be explained in material terms, yes! Science is really good at it.
>This argument would be stronger 500 years ago, but I don't know how one can consider this "not far from believing in magic" after seeing a computer. Or, after observing brains of different animals - from insects to simians. Or, after discovering circuit-bending and realizing how similar it is to prodding a brain. There's ample evidence against the hypothesis that the human brain is the only magical object in the universe and that it somehow transcends physics.
I cannot see how any one of those things you mentioned have to do with the utter strangeness that is subjective experience? I'm not saying a brain cannot perform computations, if that's what you're getting out of this. Why you mention a computer I don't know - there is nothing that indicates a computer has subjective experience and nothing about a computer makes me believe that creating subjective states is something that can be done with atoms alone. And that is what is 'magical' about this line of reasoning.
>Why? If I gave you a device that could trace the state of every molecule and charge in my brain to the extent allowed by uncertainty principle, would you still be confident in believing that? Just because we don't have a device like this doesn't mean consciousness is magic.
See above. Even if you were to trace every molecule in my brain, you would be no closer to really explaining a subjective experience. You would be able to show correlations, yes! 'Now he's angry, look at this cluster of atoms'. But that's not an explanation of the experience as such. That's the unbridgeable gap I'm talking about.
It's successful at explaining everything that can be explained in material terms, yes! Science is really good at it.
>This argument would be stronger 500 years ago, but I don't know how one can consider this "not far from believing in magic" after seeing a computer. Or, after observing brains of different animals - from insects to simians. Or, after discovering circuit-bending and realizing how similar it is to prodding a brain. There's ample evidence against the hypothesis that the human brain is the only magical object in the universe and that it somehow transcends physics.
I cannot see how any one of those things you mentioned have to do with the utter strangeness that is subjective experience? I'm not saying a brain cannot perform computations, if that's what you're getting out of this. Why you mention a computer I don't know - there is nothing that indicates a computer has subjective experience and nothing about a computer makes me believe that creating subjective states is something that can be done with atoms alone. And that is what is 'magical' about this line of reasoning.
>Why? If I gave you a device that could trace the state of every molecule and charge in my brain to the extent allowed by uncertainty principle, would you still be confident in believing that? Just because we don't have a device like this doesn't mean consciousness is magic.
See above. Even if you were to trace every molecule in my brain, you would be no closer to really explaining a subjective experience. You would be able to show correlations, yes! 'Now he's angry, look at this cluster of atoms'. But that's not an explanation of the experience as such. That's the unbridgeable gap I'm talking about.
> See above. Even if you were to trace every molecule in my brain, you would be no closer to really explaining a subjective experience. You would be able to show correlations, yes! 'Now he's angry, look at this cluster of atoms'. But that's not an explanation of the experience as such. That's the unbridgeable gap I'm talking about.
Personally, I don't see a basis to believe there's something more to it. I'd look at the cluster of atoms in your brain and say this is anger. This is the computational process that is anger in your brain. I don't see a meaningful difference between this and doing the same to a computer - I could point at a cluster of atoms and EM fields in the CPU and say, "this is factorization of numbers; this is how the cryptographic routine this CPU executes manifests". Why would there be anything else here?
Personally, I don't see a basis to believe there's something more to it. I'd look at the cluster of atoms in your brain and say this is anger. This is the computational process that is anger in your brain. I don't see a meaningful difference between this and doing the same to a computer - I could point at a cluster of atoms and EM fields in the CPU and say, "this is factorization of numbers; this is how the cryptographic routine this CPU executes manifests". Why would there be anything else here?
I see this kind of debate between people often. I think the crucial point is the "feeling" that is the subjective experience.
Some people feel there is no way for such a "feeling" to form spontaneously out of the cold, dead matter. Since some matter doesn't experience this feeling, how does it spontaneously form, out of no-feeling, at some threshold configuration? What is this threshold exactly? These people think it must special, since we can imagine (in principle) a clump of matter interacting physically in time to simulate the external appearance of a human mind, yet remain no-feeling on the inside.
Other people don't seem to grasp what the problem the first people are posing might possibly be. The "feeling" is simply a property of the universe which arises in some physical configurations. Computers can have subjective experience and even today's computers might have it in some form. There is no discrete, magical step required.
I find myself continually switching teams on this matter. The second position might be more believable after we find some laws governing the relationship between physical configurations and the nature of the resulting experience. But since subjective experience is necessarily... subjective, it seems very hard (impossible?) to test.
Some people feel there is no way for such a "feeling" to form spontaneously out of the cold, dead matter. Since some matter doesn't experience this feeling, how does it spontaneously form, out of no-feeling, at some threshold configuration? What is this threshold exactly? These people think it must special, since we can imagine (in principle) a clump of matter interacting physically in time to simulate the external appearance of a human mind, yet remain no-feeling on the inside.
Other people don't seem to grasp what the problem the first people are posing might possibly be. The "feeling" is simply a property of the universe which arises in some physical configurations. Computers can have subjective experience and even today's computers might have it in some form. There is no discrete, magical step required.
I find myself continually switching teams on this matter. The second position might be more believable after we find some laws governing the relationship between physical configurations and the nature of the resulting experience. But since subjective experience is necessarily... subjective, it seems very hard (impossible?) to test.
The problem with that line of reasoning is you're assuming the brain is a computer, or that it merely computes.
But that's just an assumption and there are many reasons a person, let alone a brain, is not a machine or a computer or an algorithm. That it is like it? Sure, in some insignificant ways, we have the ability to compute things. But is it an algorithm? No.
The idea that consciousness is an algorithm or a computer or a machine is an assumption that is extremely popular among people in the tech industry because it confirms their assumptions, and it makes them feel like they have extremely transferable knowledge. "I know about computers. Let's assume the brain is a computer and consciousness is an algorithm. I can now comment on the brain and consciousness."
But there is very little reason to accept that assumption. This review of Harai's Homo Deus does a great job of pointing out the dead-ends that assumption leads you to. [review](https://inference-review.com/article/godzooks#When:00:35:00Z)
But that's just an assumption and there are many reasons a person, let alone a brain, is not a machine or a computer or an algorithm. That it is like it? Sure, in some insignificant ways, we have the ability to compute things. But is it an algorithm? No.
The idea that consciousness is an algorithm or a computer or a machine is an assumption that is extremely popular among people in the tech industry because it confirms their assumptions, and it makes them feel like they have extremely transferable knowledge. "I know about computers. Let's assume the brain is a computer and consciousness is an algorithm. I can now comment on the brain and consciousness."
But there is very little reason to accept that assumption. This review of Harai's Homo Deus does a great job of pointing out the dead-ends that assumption leads you to. [review](https://inference-review.com/article/godzooks#When:00:35:00Z)
> The problem with that line of reasoning is you're assuming the brain is a computer, or that it merely computes.
The brain can compute. That's extraordinary. I say one type of thing does that, computers. You say no, two things, computers and then also brains. But when pressed to explain what is a brain if not a computer you'll just sputter (probably at length) without offering any substance.
In a sense that's the wrong way up to explain it. Church-Turing intuitively defines computation (the things computers can do) in terms of what our brains can do, so the match is not a coincidence but it also isn't there for the reason you probably expect. Because it's an intuition Church-Turing isn't provable, but you may notice that we subsequently built an _entire world-changing industry_ upon it in a lifetime.
You pointed to a review, others have written entire books, always they can be summarised as simply arguments from incredulity. "What? Nonsense, the brain can't be a computer, I simply won't believe that". It's unfortunate that we have woken such people from their daydreaming, I have no doubt that if similarly aroused they'd give the mathematicians what for too, "What? Nonsense, how can there be numbers which aren't ratios of whole numbers, I simply won't believe it".
The brain can compute. That's extraordinary. I say one type of thing does that, computers. You say no, two things, computers and then also brains. But when pressed to explain what is a brain if not a computer you'll just sputter (probably at length) without offering any substance.
In a sense that's the wrong way up to explain it. Church-Turing intuitively defines computation (the things computers can do) in terms of what our brains can do, so the match is not a coincidence but it also isn't there for the reason you probably expect. Because it's an intuition Church-Turing isn't provable, but you may notice that we subsequently built an _entire world-changing industry_ upon it in a lifetime.
You pointed to a review, others have written entire books, always they can be summarised as simply arguments from incredulity. "What? Nonsense, the brain can't be a computer, I simply won't believe that". It's unfortunate that we have woken such people from their daydreaming, I have no doubt that if similarly aroused they'd give the mathematicians what for too, "What? Nonsense, how can there be numbers which aren't ratios of whole numbers, I simply won't believe it".
> The brain can compute.
You'll see in my comment and your quote that I don't say the brain can't compute. I agree, the brain can compute. But that doesn't mean it is a computer, because computing is an ability. People can do many other things aside from computing, none of which rely on computation, for instance they can imagine, which is the ability to think new thoughts. Computers can't imagine because all they do is compute: that's their programming. No amount of programming can produce imagination. Computation and imagination are categorically distinct as different intellectual powers and abilities.
You are conflating an ability with ontology. We know what a brain is. It's a collection of fatty material with neurons that do not explicitly fire exactly like a computer. Key word there is like. Church-Turing built a model of computational logic off of intuitions about the brain and formal mathematical logic. That's it's not provable doesn't prove your point; it removes any distinction between it being right or wrong: because it is a model (lets make something like the brain).
That an industry was built on computation doesn't prove anything. We know computation is an ability. For instance it's also something we can do with abacuses. We could have built an enormous industry on building elaborate abacuses. We built computers do be extremely fast at computation. We didn't build computers to be brains.
You'll notice, if you read the review, that the author of the review repeatedly cites cognitive neuroscientists, even evangelists of the singularity, philosophers, psychologists, and zoologists, who have published at length on this topic and repeatedly critcise and disrupt the simple idea that the brain is a computer or an algorithm or even a machine. An entire branch of philosophy developed off of Ludwig Wittgenstein to counter the computational model of consciousness. Numerous books in the Philosophy of Mind argue that the assumption that the brain is a computer is not just unsupported, it is logically nonsensical.
You'll see in my comment and your quote that I don't say the brain can't compute. I agree, the brain can compute. But that doesn't mean it is a computer, because computing is an ability. People can do many other things aside from computing, none of which rely on computation, for instance they can imagine, which is the ability to think new thoughts. Computers can't imagine because all they do is compute: that's their programming. No amount of programming can produce imagination. Computation and imagination are categorically distinct as different intellectual powers and abilities.
You are conflating an ability with ontology. We know what a brain is. It's a collection of fatty material with neurons that do not explicitly fire exactly like a computer. Key word there is like. Church-Turing built a model of computational logic off of intuitions about the brain and formal mathematical logic. That's it's not provable doesn't prove your point; it removes any distinction between it being right or wrong: because it is a model (lets make something like the brain).
That an industry was built on computation doesn't prove anything. We know computation is an ability. For instance it's also something we can do with abacuses. We could have built an enormous industry on building elaborate abacuses. We built computers do be extremely fast at computation. We didn't build computers to be brains.
You'll notice, if you read the review, that the author of the review repeatedly cites cognitive neuroscientists, even evangelists of the singularity, philosophers, psychologists, and zoologists, who have published at length on this topic and repeatedly critcise and disrupt the simple idea that the brain is a computer or an algorithm or even a machine. An entire branch of philosophy developed off of Ludwig Wittgenstein to counter the computational model of consciousness. Numerous books in the Philosophy of Mind argue that the assumption that the brain is a computer is not just unsupported, it is logically nonsensical.
"No amount of programming can produce imagination" is a very bold statement to make.
The brain exists in a physical universe, made out of matter/energy, and its behaviours are entirely dictated by the laws of physics; that's a fairly accepted truth unless you have solid evidence otherwise.
The laws of physics are mathematical and can be computed by their very nature, and we are already pretty good at simulating physical interactions to a quantum level, and this ability improves over time.
At some point in time, unless there is "magic" or missing physics, a sufficiently powerful computer with a physically accurate simulation of a brain would produce virtually identical results to a real brain.
So either there must be new physics involved, or, the notion that a sufficiently advanced computer simulation can't produce imagination must be abandoned.
A team of scientists able to sufficiently model the physics of the brain (and presumably the entire central nervous system, I imagine a disembodied brain simulation would experience a horrific form of locked-in syndrome) would not need to be concerned about emergent properties of the simulation such as a sense of consciousness, or thought, or imagination. Those things will just happen once the simulation is perfected.
Indeed the cognitive neuroscience folk, etc, would be invaluable to actually understanding, training, interpreting and caring for the brain simulation, and figuring out if its behaviours and interactions constitute consciousness etc, so I do not think this has to even be framed as programmers pretending to know about brain stuff vs brain people who dismiss any notion of computationally recreating consciousness. It would be a team effort that works both ways, but is already doomed to fail if half the team thinks it's impossible from the get-go.
The brain exists in a physical universe, made out of matter/energy, and its behaviours are entirely dictated by the laws of physics; that's a fairly accepted truth unless you have solid evidence otherwise.
The laws of physics are mathematical and can be computed by their very nature, and we are already pretty good at simulating physical interactions to a quantum level, and this ability improves over time.
At some point in time, unless there is "magic" or missing physics, a sufficiently powerful computer with a physically accurate simulation of a brain would produce virtually identical results to a real brain.
So either there must be new physics involved, or, the notion that a sufficiently advanced computer simulation can't produce imagination must be abandoned.
A team of scientists able to sufficiently model the physics of the brain (and presumably the entire central nervous system, I imagine a disembodied brain simulation would experience a horrific form of locked-in syndrome) would not need to be concerned about emergent properties of the simulation such as a sense of consciousness, or thought, or imagination. Those things will just happen once the simulation is perfected.
Indeed the cognitive neuroscience folk, etc, would be invaluable to actually understanding, training, interpreting and caring for the brain simulation, and figuring out if its behaviours and interactions constitute consciousness etc, so I do not think this has to even be framed as programmers pretending to know about brain stuff vs brain people who dismiss any notion of computationally recreating consciousness. It would be a team effort that works both ways, but is already doomed to fail if half the team thinks it's impossible from the get-go.
It's not a remotely bold statement. Think about what imagination is, and then think about whether computers can imagine. Computers can't imagine. Computers can't come up with new things because they are programmed. Programming prescribes the outputs to the same limitations as the inputs: it's a closed deterministic system.
You'll see in my comment above this one that I agree that the brain is a physical thing. But abilities and powers are not physical. That's not voodoo magic. That's what abilities are. Think about horsepower. The horsepower of a car does not reside in any one physical thing, not the carburetor, or the intake manifold, or the piston, or the wheels; it's an ability of the car: it is able to go at such and such horsepower. That is what horsepower is.
The same applies to computation. Computing something is an ability, but we have many more intellectual and cognitive abilities beside computing things.
As a result
> a sufficiently powerful computer with a physically accurate simulation of a brain would produce virtually identical results to a real brain.
is just you are assuming that it will work, but nothing about computers supports that in the slightest. That's just a guess.
> A team of scientists able to sufficiently model the physics of the brain (and presumably the entire central nervous system, I imagine a disembodied brain simulation would experience a horrific form of locked-in syndrome) would not need to be concerned about emergent properties of the simulation such as a sense of consciousness, or thought, or imagination. Those things will just happen once the simulation is perfected.
All of this is still an assumption.
Again, that doesn't mean you are right or wrong: it means its an assumption. You have to accept the limitations of your assumption and the limitations of modelling the brain on a computer are large and glaring.
> Indeed the cognitive neuroscience folk, etc, would be invaluable to actually understanding, training, interpreting and caring for the brain simulation, and figuring out if its behaviours and interactions constitute consciousness etc, so I do not think this has to even be framed as programmers pretending to know about brain stuff vs brain people who dismiss any notion of computationally recreating consciousness. It would be a team effort that works both ways, but is already doomed to fail if half the team thinks it's impossible from the get-go.
You are assuming here that only the programmers are heading down the right path. But you don't know that. It's entirely reasonable (and I would say much more supportable) to say that the programmers are heading down the wrong path: their path will lead to nothing at all. That's because the programmers have fallen to a category error.
You think they need to model the brain on a computer for it to make sense. But there is actually very little if anything to support that.
Brains are brains. Computers are computers. That computer science can be fuzzily applied to the study of brains around the ability to compute does not mean the study of brains is computer science or that brains are computers.
You'll see in my comment above this one that I agree that the brain is a physical thing. But abilities and powers are not physical. That's not voodoo magic. That's what abilities are. Think about horsepower. The horsepower of a car does not reside in any one physical thing, not the carburetor, or the intake manifold, or the piston, or the wheels; it's an ability of the car: it is able to go at such and such horsepower. That is what horsepower is.
The same applies to computation. Computing something is an ability, but we have many more intellectual and cognitive abilities beside computing things.
As a result
> a sufficiently powerful computer with a physically accurate simulation of a brain would produce virtually identical results to a real brain.
is just you are assuming that it will work, but nothing about computers supports that in the slightest. That's just a guess.
> A team of scientists able to sufficiently model the physics of the brain (and presumably the entire central nervous system, I imagine a disembodied brain simulation would experience a horrific form of locked-in syndrome) would not need to be concerned about emergent properties of the simulation such as a sense of consciousness, or thought, or imagination. Those things will just happen once the simulation is perfected.
All of this is still an assumption.
Again, that doesn't mean you are right or wrong: it means its an assumption. You have to accept the limitations of your assumption and the limitations of modelling the brain on a computer are large and glaring.
> Indeed the cognitive neuroscience folk, etc, would be invaluable to actually understanding, training, interpreting and caring for the brain simulation, and figuring out if its behaviours and interactions constitute consciousness etc, so I do not think this has to even be framed as programmers pretending to know about brain stuff vs brain people who dismiss any notion of computationally recreating consciousness. It would be a team effort that works both ways, but is already doomed to fail if half the team thinks it's impossible from the get-go.
You are assuming here that only the programmers are heading down the right path. But you don't know that. It's entirely reasonable (and I would say much more supportable) to say that the programmers are heading down the wrong path: their path will lead to nothing at all. That's because the programmers have fallen to a category error.
You think they need to model the brain on a computer for it to make sense. But there is actually very little if anything to support that.
Brains are brains. Computers are computers. That computer science can be fuzzily applied to the study of brains around the ability to compute does not mean the study of brains is computer science or that brains are computers.
parksy(1)
Not so extraordinary. What's extraordinary isn't that brains can compute, it's that anything else can. Brains computing is ordinary. What's extraordinary about the brain isn't that it can compute. What's extraordinary about the brain is that it can be rational and self-aware, things that computers cannot do. Computers can only be deterministic. Brains can be deterministic, but they can also be non-deterministic
Computers can become non-deterministic in practice as soon as you botch your random number handling, or hook your input up to environmental noise. Is there anything suggesting the brain is non-deterministic in a theoretical way, not just the way computers are?
Deterministic means that given the same input, the system gives the same output. Computers would be useless if they were not deterministic. Hooking up random input to a deterministic process will give random output. Garbage in, garbage out.
What you're asking is for computers to be rational. That given garbage input, it will produce intelligible output. Computers cannot do this unless you program them to.
Human minds are non-deterministic in many, many, many ways. Hand the same input to the same mind and you'll get a different output every single time, unless the mind willed itself to act rationally. But they are deterministic enough that you can study their behavior. Other brains are not as non-deterministic, so their behavior is easier to study.
Look at it from a thermodynamic standpoint. Biological systems arose to conserve order against entropy. A fully-deterministic system will shed order, it's only through non-deterministic means that biological systems can conserve order.
The mind is the most complex system nature has devised that can not only slow the aggregation of entropy, but also create order! It's not breaking the laws of physics, but yet it can create all kinds of order.
Conway's Game of Life is an excellent illustration of the concept. You have to work hard and study the domain in order to find stable systems. Otherwise they just drop to equilibrium fast.
What you're asking is for computers to be rational. That given garbage input, it will produce intelligible output. Computers cannot do this unless you program them to.
Human minds are non-deterministic in many, many, many ways. Hand the same input to the same mind and you'll get a different output every single time, unless the mind willed itself to act rationally. But they are deterministic enough that you can study their behavior. Other brains are not as non-deterministic, so their behavior is easier to study.
Look at it from a thermodynamic standpoint. Biological systems arose to conserve order against entropy. A fully-deterministic system will shed order, it's only through non-deterministic means that biological systems can conserve order.
The mind is the most complex system nature has devised that can not only slow the aggregation of entropy, but also create order! It's not breaking the laws of physics, but yet it can create all kinds of order.
Conway's Game of Life is an excellent illustration of the concept. You have to work hard and study the domain in order to find stable systems. Otherwise they just drop to equilibrium fast.
Thermodynamics is defined in a deterministic universe. It's only through sheer amount of states any interesting system could be in that entropy arises. Chaotic systems (as studied in mathematics) are deterministic too. Conway's Game of Life is indeed an excellent illustration of the concept - of how chaotic and "surprising" behavior can arise in a fully deterministic system.
> Human minds are non-deterministic in many, many, many ways. Hand the same input to the same mind and you'll get a different output every single time
That's not non-deterministic. That's simply stateful. Most human-made systems you interact with daily are stateful, so it's not exactly surprising.
When I say "deterministic in practice" vs. "deterministic in theory" I mean this: a system is deterministic in practice if you can actually predict its outputs based on its inputs with reasonable amount of effort. A LED hooked up to a switch and a battery is deterministic in practice. So is a program computing GCD on 32-bit integers. A system is deterministic in theory if it's deterministic, but actually predicting its outputs requires absurd amount of computation. Lorenz system and weather are two examples. So is protein folding and turbulent flow. I see no reason why a fly brain, a mouse brain, or a human brain wouldn't be such systems either. The entire universe could be one, if you subscribe to many-worlds interpretation of quantum mechanics.
> Human minds are non-deterministic in many, many, many ways. Hand the same input to the same mind and you'll get a different output every single time
That's not non-deterministic. That's simply stateful. Most human-made systems you interact with daily are stateful, so it's not exactly surprising.
When I say "deterministic in practice" vs. "deterministic in theory" I mean this: a system is deterministic in practice if you can actually predict its outputs based on its inputs with reasonable amount of effort. A LED hooked up to a switch and a battery is deterministic in practice. So is a program computing GCD on 32-bit integers. A system is deterministic in theory if it's deterministic, but actually predicting its outputs requires absurd amount of computation. Lorenz system and weather are two examples. So is protein folding and turbulent flow. I see no reason why a fly brain, a mouse brain, or a human brain wouldn't be such systems either. The entire universe could be one, if you subscribe to many-worlds interpretation of quantum mechanics.
> I mean this: a system is deterministic in practice if you can actually predict its outputs based on its inputs with reasonable amount of effort.
You're changing the meaning of determinism and bringing it closer to rationalism. Your introduction of the element of theory to the mix is a violation of Occam's Razor. We already have philosophy and a word that covers what you want it to cover. Theory is a component of rationalism, not of determinism. If you need theory to understand a system, then it already has elements of non-determinism. Theory is what you need to make sense of the non-deterministic. Because theory deals with uncertainty, you wouldn't need any validation of your hypotheses if the system was truly deterministic. One observation would be enough to ascertain the whole thing.
A considered study of history would reveal where you're going wrong here. The Greeks invented empiricism and philosophy and science while the Egyptians never got there despite only being a tiny distance away. They wanted to distance themselves from theological frames. Despite all this, the Egyptians built pyramids. They understood determinism. They could not understand science. Determinism made them good engineers. Engineering is not science.
> A system is deterministic in theory if it's deterministic, but actually predicting its outputs requires absurd amount of computation.
Now you're starting to dip into computational complexity territory. Predicting outputs is the domain that the halting problem puts a backstop to.
To prove to you that a brain is better than a computer, all I have to do is state the obvious, humans make algorithms, not the other way around. Sure, there are programs that will devise algorithms, but humans have to understand the domain before they can make computers do their work for them.
Your examples of Lorenz systems and weather do not change things at all. Humans have a better understanding of weather than computers do. In fact, humans have an entire body of theory that attempts to make sense of why such things have difficult-to-determine causation, chaos theory. Humans devised it, not computers. And they devised it using the tools of epistemology, working out the details of justification of knowledge via seeking rigor, not in the scientific method of dreaming up hypotheses based on empirical analysis and testing them. Chaos theory is more math than science.
In other real ways, humans outclass other mammals, even though we largely share the same macro brain structures. We keep monkeys in cages, monkeys do not keep us in cages.
I'm not sure how much more I have to state the obvious here. You seem to be the one seeking out a special domain in which the rules don't apply, one in which computers are wholly analogous to brains. It may, and this is speculation, be true in degree rather than kind.
But the halting problem itself illustrates a domain in which humans are able to reason past, whereas we cannot possibly program a computer to do it. Computers cannot program themselves to find gradations of the halting problem. Humans have to write algo-generating algos. The pace of comp-sci progress at the moment is fully dictated by human ingenuity, and if you think about it, any change in this means that the singularity is upon us.
I suspect that we'll never be able to get computers to fully take the place of brains. There will always be domains where brains are better than algos. Prove me wrong. Humans are capable of wanting things, even the best machine learning algos at the moment struggle with finding purpose. Finding purpose is something even the most basic virus can achieve. And we can't even determine whether virii are alive or not.
And that's super basic. How much more self-awareness do you think algos can find before running into hard physical limits? The computational and memory concerns are huge. I predict the hard limit of engineered systems will be well below full self-awareness. Instead we'll have to create biological systems to carry on progress. Dogs will get smarter, mice will get smarter, apes will eventually start doing things that humans do now, once we can fit our ethics around it.
You're changing the meaning of determinism and bringing it closer to rationalism. Your introduction of the element of theory to the mix is a violation of Occam's Razor. We already have philosophy and a word that covers what you want it to cover. Theory is a component of rationalism, not of determinism. If you need theory to understand a system, then it already has elements of non-determinism. Theory is what you need to make sense of the non-deterministic. Because theory deals with uncertainty, you wouldn't need any validation of your hypotheses if the system was truly deterministic. One observation would be enough to ascertain the whole thing.
A considered study of history would reveal where you're going wrong here. The Greeks invented empiricism and philosophy and science while the Egyptians never got there despite only being a tiny distance away. They wanted to distance themselves from theological frames. Despite all this, the Egyptians built pyramids. They understood determinism. They could not understand science. Determinism made them good engineers. Engineering is not science.
> A system is deterministic in theory if it's deterministic, but actually predicting its outputs requires absurd amount of computation.
Now you're starting to dip into computational complexity territory. Predicting outputs is the domain that the halting problem puts a backstop to.
To prove to you that a brain is better than a computer, all I have to do is state the obvious, humans make algorithms, not the other way around. Sure, there are programs that will devise algorithms, but humans have to understand the domain before they can make computers do their work for them.
Your examples of Lorenz systems and weather do not change things at all. Humans have a better understanding of weather than computers do. In fact, humans have an entire body of theory that attempts to make sense of why such things have difficult-to-determine causation, chaos theory. Humans devised it, not computers. And they devised it using the tools of epistemology, working out the details of justification of knowledge via seeking rigor, not in the scientific method of dreaming up hypotheses based on empirical analysis and testing them. Chaos theory is more math than science.
In other real ways, humans outclass other mammals, even though we largely share the same macro brain structures. We keep monkeys in cages, monkeys do not keep us in cages.
I'm not sure how much more I have to state the obvious here. You seem to be the one seeking out a special domain in which the rules don't apply, one in which computers are wholly analogous to brains. It may, and this is speculation, be true in degree rather than kind.
But the halting problem itself illustrates a domain in which humans are able to reason past, whereas we cannot possibly program a computer to do it. Computers cannot program themselves to find gradations of the halting problem. Humans have to write algo-generating algos. The pace of comp-sci progress at the moment is fully dictated by human ingenuity, and if you think about it, any change in this means that the singularity is upon us.
I suspect that we'll never be able to get computers to fully take the place of brains. There will always be domains where brains are better than algos. Prove me wrong. Humans are capable of wanting things, even the best machine learning algos at the moment struggle with finding purpose. Finding purpose is something even the most basic virus can achieve. And we can't even determine whether virii are alive or not.
And that's super basic. How much more self-awareness do you think algos can find before running into hard physical limits? The computational and memory concerns are huge. I predict the hard limit of engineered systems will be well below full self-awareness. Instead we'll have to create biological systems to carry on progress. Dogs will get smarter, mice will get smarter, apes will eventually start doing things that humans do now, once we can fit our ethics around it.
>Hand the same input to the same mind and you'll get a different output every single time, unless the mind willed itself to act rationally.
Are you sure? Remember that memory also counts as an input if it's used in a computation; it seems to me that this applies to both humans and computers.
For a harrowing account of what a mind may do when exposed to very nearly the same inputs, you may be interested in one segment from this Radiolab episode: https://www.wnycstudios.org/story/radiolab-loops
It describes a patient with transient global amnesia who has a looping conversation with her daughter. (There's a link to a video of the conversation on that page as well.) Under normal circumstances this wouldn't happen, as once you've had a conversation you also have memories of having that conversation. But if you're unable to form memories...
Are you sure? Remember that memory also counts as an input if it's used in a computation; it seems to me that this applies to both humans and computers.
For a harrowing account of what a mind may do when exposed to very nearly the same inputs, you may be interested in one segment from this Radiolab episode: https://www.wnycstudios.org/story/radiolab-loops
It describes a patient with transient global amnesia who has a looping conversation with her daughter. (There's a link to a video of the conversation on that page as well.) Under normal circumstances this wouldn't happen, as once you've had a conversation you also have memories of having that conversation. But if you're unable to form memories...
> The idea that consciousness is an algorithm or a computer or a machine is an assumption that is extremely popular among people in the tech industry because it confirms their assumptions
No, it's not because of that. It's because it is effectively a computer. Not in the vague sense of "it has stuffs connected to stuffs and there's electricity involved", but in the more specific sense that it takes inputs, produces complex outputs, has clearly identifiable hardware and indirectly identifiable software. It even has internal structure we're only beginning to understand, but that we know enough about to reasonably infer what computations happen where. There's little reason to assume there's some metaphysical mystery here, as exactly zero other things in the universe that we studied since the dawn of humanity turned out to be magic.
TL;DR: what else could it be? And before someone says "antenna", I don't buy it. "Computer" is a simpler explanation for all known facts than remote consciousness being received by the brain. See my take on this before[0]. See also: Occam's razor.
> "I know about computers. Let's assume the brain is a computer and consciousness is an algorithm. I can now comment on the brain and consciousness."
Yeah, well, sure. If I know the limit of applicability of my computer knowledge, I sure can comment on brain and consciousness. Like, I wouldn't say "it's vulnerable to SQL injection" because that would be an idiotic statement. But I could say "it implements visual processing, audio processing, collects other telemetry, and does sensor fusion in real-time in under 20 Watts, with power to spare". Because that's observation, physics, and modelling reality along a particular perspective of interest.
--
[0] - https://news.ycombinator.com/item?id=19490801
No, it's not because of that. It's because it is effectively a computer. Not in the vague sense of "it has stuffs connected to stuffs and there's electricity involved", but in the more specific sense that it takes inputs, produces complex outputs, has clearly identifiable hardware and indirectly identifiable software. It even has internal structure we're only beginning to understand, but that we know enough about to reasonably infer what computations happen where. There's little reason to assume there's some metaphysical mystery here, as exactly zero other things in the universe that we studied since the dawn of humanity turned out to be magic.
TL;DR: what else could it be? And before someone says "antenna", I don't buy it. "Computer" is a simpler explanation for all known facts than remote consciousness being received by the brain. See my take on this before[0]. See also: Occam's razor.
> "I know about computers. Let's assume the brain is a computer and consciousness is an algorithm. I can now comment on the brain and consciousness."
Yeah, well, sure. If I know the limit of applicability of my computer knowledge, I sure can comment on brain and consciousness. Like, I wouldn't say "it's vulnerable to SQL injection" because that would be an idiotic statement. But I could say "it implements visual processing, audio processing, collects other telemetry, and does sensor fusion in real-time in under 20 Watts, with power to spare". Because that's observation, physics, and modelling reality along a particular perspective of interest.
--
[0] - https://news.ycombinator.com/item?id=19490801
> It's because it is effectively a computer. Not in the vague sense of "it has stuffs connected to stuffs and there's electricity involved", but in the more specific sense that it takes inputs, produces complex outputs, has clearly identifiable hardware and indirectly identifiable software. It even has internal structure we're only beginning to understand, but that we know enough about to reasonably infer what computations happen where. There's little reason to assume there's some metaphysical mystery here, as exactly zero other things in the universe that we studied since the dawn of humanity turned out to be magic.
You're conflating the ability to compute with ontology. Computers compute. That's all they do. They're programmed to do only that. Humans have other abilities, such as imagination, that are not computational. Computers cannot imagine, not because of limited hardware or software; they can't imagine because they only compute. Imagination isn't computational. All throughout your response you are using the terminology of computers and software as if they are completely intuitive, but we have other terminology to define those things: medical terms define parts as the brain as parts of the brain not as hardware because that's a metaphor; the cerebelum is like this part of the computer. What they are is not the same as what they can do. That's not some magical mystery, or even obscure metaphysics. A car's horsepower is not in its carburetor, or its gas, or its manifold, because the horsepower of a car is what it can do, its an ability, a power. In the same sense the brain can compute, but that doesn't mean it is a computer.
What else could it be? A brain. Animals have them. They are not computers. But they can compute. The field of computer science and software development only slightly aligns with studying the brain.
> If I know the limit of applicability of my computer knowledge, I sure can comment on brain and consciousness.
Yes and when it is no longer applicable it is no longer right or wrong: it's just assumption. That you can fuzzily attach assumptions to arguments about the brain does not mean the brain is a computer. It means you can fuzzily model the brain on a computer, but that model will have glaring gaps. You can build from your assumptions but you have to accept the limitations of that assumption. Assuming the brain is a computer comes with glaring limitations.
You're conflating the ability to compute with ontology. Computers compute. That's all they do. They're programmed to do only that. Humans have other abilities, such as imagination, that are not computational. Computers cannot imagine, not because of limited hardware or software; they can't imagine because they only compute. Imagination isn't computational. All throughout your response you are using the terminology of computers and software as if they are completely intuitive, but we have other terminology to define those things: medical terms define parts as the brain as parts of the brain not as hardware because that's a metaphor; the cerebelum is like this part of the computer. What they are is not the same as what they can do. That's not some magical mystery, or even obscure metaphysics. A car's horsepower is not in its carburetor, or its gas, or its manifold, because the horsepower of a car is what it can do, its an ability, a power. In the same sense the brain can compute, but that doesn't mean it is a computer.
What else could it be? A brain. Animals have them. They are not computers. But they can compute. The field of computer science and software development only slightly aligns with studying the brain.
> If I know the limit of applicability of my computer knowledge, I sure can comment on brain and consciousness.
Yes and when it is no longer applicable it is no longer right or wrong: it's just assumption. That you can fuzzily attach assumptions to arguments about the brain does not mean the brain is a computer. It means you can fuzzily model the brain on a computer, but that model will have glaring gaps. You can build from your assumptions but you have to accept the limitations of that assumption. Assuming the brain is a computer comes with glaring limitations.
> A car's horsepower is not in its carburetor, or its gas, or its manifold, because the horsepower of a car is what it can do, its an ability, a power. In the same sense the brain can compute, but that doesn't mean it is a computer.
A car's horsepower is in the engine. That's what an engine does. Burns fuel, provides work over time. Work over time is denominated in horsepower - or, in saner company, in watts. Categories like "engine" or "computer" are not excluding. That thing in the car can be "an engine", "a hunk of metal" and "an expensive paperweight" at the same time. Similarly, if brain can compute, it is a computer. It's also an organ.
> Humans have other abilities, such as imagination, that are not computational.
Evidence needed. Why would it not be computational? We can, and do, easily build imagination-like computations. A fuzzy search on a graph. A series of simulations with relaxed constraints and somewhat randomized initial states. They all resemble aspects of imagination; it's not a big leap to conclude that imagination is nothing but a more complex variant of such computations.
> It means you can fuzzily model the brain on a computer, but that model will have glaring gaps.
Models exist on a map, not in the territory. So do brains and computers. The territory is made of whatever sub-quark substrate the reality is made of. When you say "brain", what you're really referring to is a model, and a pretty black-boxy one. Viewing the brain as a computer is an attempt to apply a model that's little more transparent (and therefore more useful); as long as it matches observable evidence (and it does), it's the right thing to do.
A car's horsepower is in the engine. That's what an engine does. Burns fuel, provides work over time. Work over time is denominated in horsepower - or, in saner company, in watts. Categories like "engine" or "computer" are not excluding. That thing in the car can be "an engine", "a hunk of metal" and "an expensive paperweight" at the same time. Similarly, if brain can compute, it is a computer. It's also an organ.
> Humans have other abilities, such as imagination, that are not computational.
Evidence needed. Why would it not be computational? We can, and do, easily build imagination-like computations. A fuzzy search on a graph. A series of simulations with relaxed constraints and somewhat randomized initial states. They all resemble aspects of imagination; it's not a big leap to conclude that imagination is nothing but a more complex variant of such computations.
> It means you can fuzzily model the brain on a computer, but that model will have glaring gaps.
Models exist on a map, not in the territory. So do brains and computers. The territory is made of whatever sub-quark substrate the reality is made of. When you say "brain", what you're really referring to is a model, and a pretty black-boxy one. Viewing the brain as a computer is an attempt to apply a model that's little more transparent (and therefore more useful); as long as it matches observable evidence (and it does), it's the right thing to do.
Sorry, I didn't see that you'd replied to my comment until today.
> A car's horsepower is in the engine.
Where is it in the engine? The engine can go 180hp. But the engine does not contain 180 hp. That's what the concept of an ability or a power is. A broken engine cannot go 180 hp. But, if as you say, it is in the engine, then that distinction would be irrelevant. We would still say a broken engine can go 180 hp. But we don't.
> Similarly, if brain can compute, it is a computer. It's also an organ.
Right, you'll see I have never said the brain can't compute. But that doesn't mean it is simply a computer. If the assumption that the brain is a computer is to stand then the abilities of a computer should be compared to the abilities of a brain, or a person. There are those that match. We agree on that. But there are those that do not. And that means the assumption that the brain simply is a computer is flawed. It is an organ that can compute. But to extend from that that it is a computer is eliding the crucial difference between the two. That is your assumption.
> Evidence needed. Why would it [imagination] not be computational?
Let's ignore that the premise you are making: that imagination is computational, requires you to support it as well;
> imagination-like computations
> A fuzzy search on a graph
> A series of simulations with relaxed constraints and somewhat randomized initial states
All require you to posit things that are -like, or somewhat like imagination. But computers are programmed. They can't think new thoughts. They are closed deterministic systems. That their output seems imaginative or novel does not mean the computer has the ability to imagine, it means the computational output was unexpected to you or the people who wrote the code. The idea that imagination is computational is a category error.
> not a big leap to conclude that imagination is nothing but a more complex variant of such computations
This is actually an enormous leap. Can computers imagine? You will find zero agreement in that regard. That doesn't prove your point. You'll need to provide evidence that computers can actually violate their programming, cannot just compute and instead imagine. But that's not what computers do. Computers compute. That they can do things that seem like imagination to you does not mean they can imagine.
>> It means you can fuzzily model the brain on a computer, but that model will have glaring gaps.
> Models exist on a map, not in the territory. So do brains and computers. The territory is made of whatever sub-quark substrate the reality is made of. When you say "brain", what you're really referring to is a model, and a pretty black-boxy one. Viewing the brain as a computer is an attempt to apply a model that's little more transparent (and therefore more useful); as long as it matches observable evidence (and it does), it's the right thing to do.
Excuse my original words, I meant "fuzzily model the brain as a computer
Again, I don't think applying the computer as a model is completely invalid. But it has limitations. You can't just brush off those limitations when you talk about the brain as a computer. They fundamentally mean the comparison is less useful. Supposing it is 1 to 1, which you are doing leads you to build on assumptions that are unsupported. You have to accept that the assumption that the brain is a computer has serious criticisms brought against it. And you have to defend that assumption. You can't simply ignore them and argue that you are right.
For instance viewing the brain as computer frequently does not match the observable evidence. We can imagine. Computers cannot. That is observable. So how do you support the assumption that the brain is a computer in spite of that?
> A car's horsepower is in the engine.
Where is it in the engine? The engine can go 180hp. But the engine does not contain 180 hp. That's what the concept of an ability or a power is. A broken engine cannot go 180 hp. But, if as you say, it is in the engine, then that distinction would be irrelevant. We would still say a broken engine can go 180 hp. But we don't.
> Similarly, if brain can compute, it is a computer. It's also an organ.
Right, you'll see I have never said the brain can't compute. But that doesn't mean it is simply a computer. If the assumption that the brain is a computer is to stand then the abilities of a computer should be compared to the abilities of a brain, or a person. There are those that match. We agree on that. But there are those that do not. And that means the assumption that the brain simply is a computer is flawed. It is an organ that can compute. But to extend from that that it is a computer is eliding the crucial difference between the two. That is your assumption.
> Evidence needed. Why would it [imagination] not be computational?
Let's ignore that the premise you are making: that imagination is computational, requires you to support it as well;
> imagination-like computations
> A fuzzy search on a graph
> A series of simulations with relaxed constraints and somewhat randomized initial states
All require you to posit things that are -like, or somewhat like imagination. But computers are programmed. They can't think new thoughts. They are closed deterministic systems. That their output seems imaginative or novel does not mean the computer has the ability to imagine, it means the computational output was unexpected to you or the people who wrote the code. The idea that imagination is computational is a category error.
> not a big leap to conclude that imagination is nothing but a more complex variant of such computations
This is actually an enormous leap. Can computers imagine? You will find zero agreement in that regard. That doesn't prove your point. You'll need to provide evidence that computers can actually violate their programming, cannot just compute and instead imagine. But that's not what computers do. Computers compute. That they can do things that seem like imagination to you does not mean they can imagine.
>> It means you can fuzzily model the brain on a computer, but that model will have glaring gaps.
> Models exist on a map, not in the territory. So do brains and computers. The territory is made of whatever sub-quark substrate the reality is made of. When you say "brain", what you're really referring to is a model, and a pretty black-boxy one. Viewing the brain as a computer is an attempt to apply a model that's little more transparent (and therefore more useful); as long as it matches observable evidence (and it does), it's the right thing to do.
Excuse my original words, I meant "fuzzily model the brain as a computer
Again, I don't think applying the computer as a model is completely invalid. But it has limitations. You can't just brush off those limitations when you talk about the brain as a computer. They fundamentally mean the comparison is less useful. Supposing it is 1 to 1, which you are doing leads you to build on assumptions that are unsupported. You have to accept that the assumption that the brain is a computer has serious criticisms brought against it. And you have to defend that assumption. You can't simply ignore them and argue that you are right.
For instance viewing the brain as computer frequently does not match the observable evidence. We can imagine. Computers cannot. That is observable. So how do you support the assumption that the brain is a computer in spite of that?
Computers "imagine" things all the time. The fact that we do not use the word "imagine" to describe it is immaterial. Words to not dictate the behavior.
> as exactly zero other things in the universe that we studied since the dawn of humanity turned out to be magic.
Rather, the things that seem somehow magical to us we either explain scientifically, or we ignore. I don't know about you, but several of my acquaintances have reported phenomena and experiences that I have no reason to doubt, that are not solely 'in their mind' (because of the external consequences of what happened), and that cannot be explained by mechanistic laws because they involve 'backwards' transfer of information and so on. These are datapoints, they're just unfortunately not datapoints that can be used for scientific inquiry. But then again, there is no a priori reason to believe science can answer all questions we have.
Regardless of this, there is a reason to assume a big metaphysical mystery, simply because consciousness and subjectivity is unlike anything else in the world and bridging the qualitative gap between subjective experience and the mechanistical world is a completely different task than explaining, say, what makes a stone roll the way it does.
Rather, the things that seem somehow magical to us we either explain scientifically, or we ignore. I don't know about you, but several of my acquaintances have reported phenomena and experiences that I have no reason to doubt, that are not solely 'in their mind' (because of the external consequences of what happened), and that cannot be explained by mechanistic laws because they involve 'backwards' transfer of information and so on. These are datapoints, they're just unfortunately not datapoints that can be used for scientific inquiry. But then again, there is no a priori reason to believe science can answer all questions we have.
Regardless of this, there is a reason to assume a big metaphysical mystery, simply because consciousness and subjectivity is unlike anything else in the world and bridging the qualitative gap between subjective experience and the mechanistical world is a completely different task than explaining, say, what makes a stone roll the way it does.
> I don't know about you, but several of my acquaintances have reported phenomena and experiences that I have no reason to doubt, that are not solely 'in their mind' (because of the external consequences of what happened), and that cannot be explained by mechanistic laws because they involve 'backwards' transfer of information and so on.
I have those too, and no offense to you personally, but I call bullshit on both mine and your acquaintances. In case of people I know, there was not one situation for which I couldn't find a more plausible explanation - which usually boils down to that for enough trials, even the rare coincidences sometimes happen.
> there is no a priori reason to believe science can answer all questions we have.
There is this one reason that it's literally the job of science. Science isn't a bunch of fixed methods from a holy book, it's the aggregation of everything that reliably works for extracting information about observable reality. And to be clear - I'm not saying that as someone who has Faith in Science (as opposed to religion). It's just that the sentence "science can't ever answer a question about reality" is a category error - it's saying "the set of ways you can answer questions about reality with can't be used to answer a question about reality". Nonsense.
> consciousness and subjectivity is unlike anything else in the world and bridging the qualitative gap between subjective experience and the mechanistical world is a completely different task than explaining, say, what makes a stone roll the way it does
But is it? The hint is given by the fact that there's more than one thinking human in existence. You may feel that answers about your subjective experiences are out of reach of science, but to the extent subjective experiences have any impact on reality, you can use science to study my subjective experiences (as expressed by me), and I can do the same to you.
I have those too, and no offense to you personally, but I call bullshit on both mine and your acquaintances. In case of people I know, there was not one situation for which I couldn't find a more plausible explanation - which usually boils down to that for enough trials, even the rare coincidences sometimes happen.
> there is no a priori reason to believe science can answer all questions we have.
There is this one reason that it's literally the job of science. Science isn't a bunch of fixed methods from a holy book, it's the aggregation of everything that reliably works for extracting information about observable reality. And to be clear - I'm not saying that as someone who has Faith in Science (as opposed to religion). It's just that the sentence "science can't ever answer a question about reality" is a category error - it's saying "the set of ways you can answer questions about reality with can't be used to answer a question about reality". Nonsense.
> consciousness and subjectivity is unlike anything else in the world and bridging the qualitative gap between subjective experience and the mechanistical world is a completely different task than explaining, say, what makes a stone roll the way it does
But is it? The hint is given by the fact that there's more than one thinking human in existence. You may feel that answers about your subjective experiences are out of reach of science, but to the extent subjective experiences have any impact on reality, you can use science to study my subjective experiences (as expressed by me), and I can do the same to you.
> Science isn't a bunch of fixed methods from a holy book, it's the aggregation of everything that reliably works for extracting information about observable reality.
This isn't true. The word is often used to describe that. But science is first and foremost a method. It's not the knowledge itself. It's not the techniques. There are other techniques besides scientific ones that we use to obtain information about the world. Math, for instance, isn't science. Statistical methods are not scientific methods.
Science concerns itself with obtaining empirical basis for causation. Studying the physical world does not provide insight into every problem we have. You don't try to debug your software problem by hooking up a multimeter to your CPU! We need to use alternative methodologies than scientific ones.
To lump them all under one word is wrong. Your categories are off, which makes your following statement:
> It's just that the sentence "science can't ever answer a question about reality" is a category error - it's saying "the set of ways you can answer questions about reality with can't be used to answer a question about reality". Nonsense."
... even more wrong.
Science is closer to a bunch of fixed methods from a holy book than it is to your assertion. You're using the word science to describe what epistemology calls justification. In epistemological terms, knowledge is a justified true belief. Science is a form of justification. There are other forms.
Since science is empirical, relying on the material world, then the assertion starts to carry water if and only if you can first prove physicalism. I personally am fully on board with materialism, but will rebel very hard against physicalism. Calling math a form of science feels very wrong. I'm on the fence about positivism, I need to think more about it.
This isn't true. The word is often used to describe that. But science is first and foremost a method. It's not the knowledge itself. It's not the techniques. There are other techniques besides scientific ones that we use to obtain information about the world. Math, for instance, isn't science. Statistical methods are not scientific methods.
Science concerns itself with obtaining empirical basis for causation. Studying the physical world does not provide insight into every problem we have. You don't try to debug your software problem by hooking up a multimeter to your CPU! We need to use alternative methodologies than scientific ones.
To lump them all under one word is wrong. Your categories are off, which makes your following statement:
> It's just that the sentence "science can't ever answer a question about reality" is a category error - it's saying "the set of ways you can answer questions about reality with can't be used to answer a question about reality". Nonsense."
... even more wrong.
Science is closer to a bunch of fixed methods from a holy book than it is to your assertion. You're using the word science to describe what epistemology calls justification. In epistemological terms, knowledge is a justified true belief. Science is a form of justification. There are other forms.
Since science is empirical, relying on the material world, then the assertion starts to carry water if and only if you can first prove physicalism. I personally am fully on board with materialism, but will rebel very hard against physicalism. Calling math a form of science feels very wrong. I'm on the fence about positivism, I need to think more about it.
> I have those too, and no offense to you personally, but I call bullshit on both mine and your acquaintances. In case of people I know, there was not one situation for which I couldn't find a more plausible explanation - which usually boils down to that for enough trials, even the rare coincidences sometimes happen.
Fair enough - this 'statistical argument' is a convenient explanation that can always be invoked, but in this case I don't really consider it to be very satisfactory as an explanation of the phenomena I have been told about (I would put the likelihood for something like those phenomena to happen 'by chance' to be so abysmally low that it seems impossible).
> There is this one reason that it's literally the job of science. Science isn't a bunch of fixed methods from a holy book, it's the aggregation of everything that reliably works for extracting information about observable reality.
I disagree. "Science (from the Latin word scientia, meaning "knowledge") is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.". This is far from saying 'science can answer any question'. But again, you're free to believe that science can do that. I just don't happen to believe it can.
> But is it? The hint is given by the fact that there's more than one thinking human in existence. You may feel that answers about your subjective experiences are out of reach of science, but to the extent subjective experiences have any impact on reality, you can use science to study my subjective experiences (as expressed by me), and I can do the same to you.
I think your answer to the other thread makes it clear that we have some insurmountable philosophical differences here. If you believe that showing the correlation between a configuration of atoms and the subjective experience that accompanies that configuration to be 'an explanation' of that subjective experience, we have very different expectations of what constitutes an explanation.
Fair enough - this 'statistical argument' is a convenient explanation that can always be invoked, but in this case I don't really consider it to be very satisfactory as an explanation of the phenomena I have been told about (I would put the likelihood for something like those phenomena to happen 'by chance' to be so abysmally low that it seems impossible).
> There is this one reason that it's literally the job of science. Science isn't a bunch of fixed methods from a holy book, it's the aggregation of everything that reliably works for extracting information about observable reality.
I disagree. "Science (from the Latin word scientia, meaning "knowledge") is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.". This is far from saying 'science can answer any question'. But again, you're free to believe that science can do that. I just don't happen to believe it can.
> But is it? The hint is given by the fact that there's more than one thinking human in existence. You may feel that answers about your subjective experiences are out of reach of science, but to the extent subjective experiences have any impact on reality, you can use science to study my subjective experiences (as expressed by me), and I can do the same to you.
I think your answer to the other thread makes it clear that we have some insurmountable philosophical differences here. If you believe that showing the correlation between a configuration of atoms and the subjective experience that accompanies that configuration to be 'an explanation' of that subjective experience, we have very different expectations of what constitutes an explanation.
I have a hard time following. I don't feel well read on the topic, but your argument seems to boil down to "our thinking is so awesome, it must be magical". This strongly reminds me of creation myths where humans desperately tried to separate themselves from all other nature. But in case I'm missing something, I'd be thankful for you answering the following few questions to get me back on track:
- Do you believe that there are laws of physics we can not perceive and understand?
- If no: Why? How does it interact with usual matter and physics? Is this the unexplainable magic?
- If we can perceive and thus hopefully one day understand all laws of physics, can we simulate them?
- If, in the future, we are able to simulate all physics, what stops us from simulating the life of a human? (though likely significantly slower)
- This simulated human should react undistinguishable form a real human. Would you call this simulated human conscious?
- If yes, then where does this consciousness come from except the simulation state?
- If no, how do we know if some other being except ourself is conscious?
- Can there be two similar beings demonstrating the same behavior, but with only one of them being conscious?
- Do you believe that there are laws of physics we can not perceive and understand?
- If no: Why? How does it interact with usual matter and physics? Is this the unexplainable magic?
- If we can perceive and thus hopefully one day understand all laws of physics, can we simulate them?
- If, in the future, we are able to simulate all physics, what stops us from simulating the life of a human? (though likely significantly slower)
- This simulated human should react undistinguishable form a real human. Would you call this simulated human conscious?
- If yes, then where does this consciousness come from except the simulation state?
- If no, how do we know if some other being except ourself is conscious?
- Can there be two similar beings demonstrating the same behavior, but with only one of them being conscious?
In order:
There certainly could be. How would we know? What if the universe isn't deterministic? Certainly it's more pragmatic to assume that only what we can experience is real, but that doesn't make it true.
The belief that there could exist parts of reality that the scientific method can't explain does not require having specific examples.
Even if all of reality can be understood by physics, that doesn't mean it can be simulated.
If physical reality can be simulated, then you could simulate the physical reality that makes up a person.
There is no guarantee that your simulation of the physical reality of a person would respond identically to an actual person.
There's a large body of philosophy on this, but basically it comes down to life working out better if we all assume everyone else is conscious.
There probably can be two similar beings demonstrating identical behavior with only one being conscious. Depends on what you define consciousness as I imagine.
I happen to lean towards believing Science can explain reality and that consciousness is a physical phenomenon, but to claim that things categorically must be that way is unfounded.
The belief that there could exist parts of reality that the scientific method can't explain does not require having specific examples.
Even if all of reality can be understood by physics, that doesn't mean it can be simulated.
If physical reality can be simulated, then you could simulate the physical reality that makes up a person.
There is no guarantee that your simulation of the physical reality of a person would respond identically to an actual person.
There's a large body of philosophy on this, but basically it comes down to life working out better if we all assume everyone else is conscious.
There probably can be two similar beings demonstrating identical behavior with only one being conscious. Depends on what you define consciousness as I imagine.
I happen to lean towards believing Science can explain reality and that consciousness is a physical phenomenon, but to claim that things categorically must be that way is unfounded.
I have no problem with seeing myself 'part of nature' - in fact, I have for the longest time believed that consciousness can be explained in terms of the material universe revealed by science alone. But I see no way in which this gap can be bridged in terms of what we currently know about the physical universe.
As for your questions: - There seems to be aspects of the universe that are related to 'meaning' rather than to 'mechanics'. How that is related to the physical universe I certainly have no theory that hasn't been thought of before. Perhaps the physical world is the 'shadow' of the world of 'meaning'/spirit? I don't really know.
- We can certainly simulate all laws of physics as detectable by science. Whether that's all there is, however, is something I don't believe.
- Leaving the debate of free will aside, I certainly don't think we'll be able to simulate the life of a human in its completeness (unless we're somehow given some insight into how subjectiveness can exist in this universe) - i.e. including the subjective dimension of that human's life.
- Thus, I wouldn't call that human conscious, no.
- We can't :) Our own conscious experience is all we can be completely sure of (which is why I also find it so extremely odd to prefer the 'mechanistic worldview' when that involves disregarding our own conscious experience, which is the only thing we really have to start from!)
- In principle, I think so, yes, but only by somehow pre-programming that unconscious being to act in exactly the same way (this relates to the concept of free will).
As you can see, I don't have a clear theory of consciousness - mine is mostly a negative position in the sense that I don't believe matter, as described by the laws of physics, can give a coherent explanation of the phenomenon of consciousness. Where to go from there is not clear, but there are a lot of philosophers of mind thinking about the issue :)
(Also, again, I don't consider this position more 'magical' than believing that arranging atoms in a given configuration will 'somehow' give rise to subjective experience).
As for your questions: - There seems to be aspects of the universe that are related to 'meaning' rather than to 'mechanics'. How that is related to the physical universe I certainly have no theory that hasn't been thought of before. Perhaps the physical world is the 'shadow' of the world of 'meaning'/spirit? I don't really know.
- We can certainly simulate all laws of physics as detectable by science. Whether that's all there is, however, is something I don't believe.
- Leaving the debate of free will aside, I certainly don't think we'll be able to simulate the life of a human in its completeness (unless we're somehow given some insight into how subjectiveness can exist in this universe) - i.e. including the subjective dimension of that human's life.
- Thus, I wouldn't call that human conscious, no.
- We can't :) Our own conscious experience is all we can be completely sure of (which is why I also find it so extremely odd to prefer the 'mechanistic worldview' when that involves disregarding our own conscious experience, which is the only thing we really have to start from!)
- In principle, I think so, yes, but only by somehow pre-programming that unconscious being to act in exactly the same way (this relates to the concept of free will).
As you can see, I don't have a clear theory of consciousness - mine is mostly a negative position in the sense that I don't believe matter, as described by the laws of physics, can give a coherent explanation of the phenomenon of consciousness. Where to go from there is not clear, but there are a lot of philosophers of mind thinking about the issue :)
(Also, again, I don't consider this position more 'magical' than believing that arranging atoms in a given configuration will 'somehow' give rise to subjective experience).
You can reproduce any algorithm with a sufficient group of people. For example, using a person as a node in a feed-forward neural network doing digit recognition. Suppose each person called the next layer in the network with the results of their calculation, until the last layer spit out a value of a digit between 1 and 9. At what point in that process does qualia arise? What is its shape and texture, and why?
Sure, I suspect "qualia" will be there, though there won't be a definite moment they arise. Imagine a simpler example: using person as a representation of a water molecule, you reproduce fluid behaviour in a crowd. At which point in this process waves arise? I suspect the question about qualia is meaningless in the same sense that asking when do water molecules (or humans) turn into waves is.
Who said our brains _needed_ consciousness to anticipate the future? The only claim I've seen is that it's (part of?) the particular mechanism our brains happen to use. This is akin to asking why birds need to flap their wings to fly when we have airplanes that can fly with fixed wings.
What I'm saying is that consciousness doesn't add anything to the art of 'predicting the future', and plays (as far as I can see) no discernable role in this art.
I would argue that consciousnes is just the feedback loop of the brain sensing itself
Because consciousness is unitary (see https://en.wikipedia.org/wiki/Integrated_information_theory), it would be intuitive if all consciously accessible information converged at a single physical location. In this theory, simple feed-forward networks aren't conscious.
From what I've read about ego-death, it doesn't seem necessary to consciously sense the self-concept, which would be self-awareness.
From what I've read about ego-death, it doesn't seem necessary to consciously sense the self-concept, which would be self-awareness.
Integrated information theory isn't proven yet. It's somewhat speculative.
I wouldn't put much weight behind ego death
I don't understand. Do you think its necessary to have a self-concept in order to exist intrinsically?
What do you mean by "exist intrinsically"?
There being a subjective perspective, having qualia, sentience: https://en.wikipedia.org/wiki/Sentience
I think the last step to feeling a sensation is knowing that you felt it. To know that you felt a sensation, the act of feeling itself needs to feedback as a sensation.
I don't think you need a well developed sense of self or philosophy of mind to be conscious. But I think from a systems point of view, the mind needs to be self sensing.
I don't think you need a well developed sense of self or philosophy of mind to be conscious. But I think from a systems point of view, the mind needs to be self sensing.
Other animals are alive and conscious, but I'm pretty sure they don't have a sense of self.
I think we will find that applying human tests for sense of self can't be applied to other animals.
Our primary test is visually based such as a mirror/marker test which doesn't work for animals that have relatively poor eyesight (dogs) or avoid eye contact (gorillas) or just don't fit our concepts of how self awareness should manifest.
Our primary test is visually based such as a mirror/marker test which doesn't work for animals that have relatively poor eyesight (dogs) or avoid eye contact (gorillas) or just don't fit our concepts of how self awareness should manifest.
Wow. This comment may change my life
Thinking of your brain as a story-fitting machine also explains a lot. Everything we perceive our brain tries to fit into a narrative structure
Very Jungian/Jordan Peterson-esque thought that I think makes a lot of sense in understanding ourselves. Also reminds me of the book The Righteous Mind.
We exist to measure ourselves in an ocean of complexity, with infinite recursion in self-awareness.
We exist to measure ourselves in an ocean of complexity, with infinite recursion in self-awareness.
Sorry to be blunt, but that's not a very good response to the Hard Problem of Consciousness. Unfeeling matter becomes feeling when its changes are related to the future? How does that work?
From the Integrated Information Theory link below:
Intrinsic existence: To account for the intrinsic existence of experience, a system constituted of elements in a state must exist intrinsically (be actual): specifically, in order to exist, it must have cause-effect power, as there is no point in assuming that something exists if nothing can make a difference to it, or if it cannot make a difference to anything. Moreover, to exist from its own intrinsic perspective, independent of external observers, a system of elements in a state must have cause-effect power upon itself, independent of extrinsic factors. Cause-effect power can be established by considering a cause-effect space with an axis for every possible state of the system in the past (causes) and future (effects).
Intrinsic existence: To account for the intrinsic existence of experience, a system constituted of elements in a state must exist intrinsically (be actual): specifically, in order to exist, it must have cause-effect power, as there is no point in assuming that something exists if nothing can make a difference to it, or if it cannot make a difference to anything. Moreover, to exist from its own intrinsic perspective, independent of external observers, a system of elements in a state must have cause-effect power upon itself, independent of extrinsic factors. Cause-effect power can be established by considering a cause-effect space with an axis for every possible state of the system in the past (causes) and future (effects).
"your brain trying to anticipate the future"
I got this worldview from Hawkins & Blakeslee's book On Intelligence. https://en.wikipedia.org/wiki/On_Intelligence
One side effect is it changed my strategy (coping mechanisms) for reality, truth, beliefs from Popperian to who has the best prediction engines. This has allowed me to disengage from contemporary rhetoric (culture wars) about science (eg creationism), allowing me to better relate to certain friends and family.
I got this worldview from Hawkins & Blakeslee's book On Intelligence. https://en.wikipedia.org/wiki/On_Intelligence
One side effect is it changed my strategy (coping mechanisms) for reality, truth, beliefs from Popperian to who has the best prediction engines. This has allowed me to disengage from contemporary rhetoric (culture wars) about science (eg creationism), allowing me to better relate to certain friends and family.
I also often consider that each day I wake up as an observer to a linked list of time, that exists independently of me yet to me "only" in my mind. As our eyes and ears are sensitive to fine vibration around us, so it seems that consciousness is sensitive to time.
I find this quote fascinating:
"What I think that means is there is no holy era of time. It emerged. If, in the distant future, we find ourselves in a universe where all the stars have burned out, and all the black holes have evaporated, and all the radiation has been diluted by the dark energy that expanded our universe, and all we have is some very cold bath of photons here and there—basically thermal equilibrium; de Sitter space, as we call it—there will be no sense of time anymore. There will nothing you can do to determine whether time is going one way or the other. Time will then have un-emerged again. It will be like the poem, This is the way the world ends / Not with a bang but a whimper."
I am not a cosmologist, but if all of space reached thermal equilibrium, if space does have any mass (perhaps a tiny amount from the dark energy it contains?), and the entire universe is essentially one uniform mass, wouldn't that mass then collapse upon itself, in a kind of big bounce?
If that is true, then time never really ends, it just "slows down" a lot (not much can happen, and not terribly quickly) until the next sparkup, whereupon time speeds up dramatically (inflationary theory).
"What I think that means is there is no holy era of time. It emerged. If, in the distant future, we find ourselves in a universe where all the stars have burned out, and all the black holes have evaporated, and all the radiation has been diluted by the dark energy that expanded our universe, and all we have is some very cold bath of photons here and there—basically thermal equilibrium; de Sitter space, as we call it—there will be no sense of time anymore. There will nothing you can do to determine whether time is going one way or the other. Time will then have un-emerged again. It will be like the poem, This is the way the world ends / Not with a bang but a whimper."
I am not a cosmologist, but if all of space reached thermal equilibrium, if space does have any mass (perhaps a tiny amount from the dark energy it contains?), and the entire universe is essentially one uniform mass, wouldn't that mass then collapse upon itself, in a kind of big bounce?
If that is true, then time never really ends, it just "slows down" a lot (not much can happen, and not terribly quickly) until the next sparkup, whereupon time speeds up dramatically (inflationary theory).
> if ... the entire universe is essentially one uniform mass, wouldn't that mass then collapse upon itself, in a kind of big bounce?
de Sitter space is a vacuum solution for Einstein's field equations.
What this means is that the stress-energy tensor is basically "canceled out" everywhere by the uniform energy distribution. That means no point in spacetime experiences any field influence. That means no gravity, that means no collapse, just stasis.
de Sitter space is a vacuum solution for Einstein's field equations.
What this means is that the stress-energy tensor is basically "canceled out" everywhere by the uniform energy distribution. That means no point in spacetime experiences any field influence. That means no gravity, that means no collapse, just stasis.
So the universe would be "de Sitting"
Is it not the case that energy has mass? Why wouldn’t this be equivalent to a uniform mass distribution?
I think you might be getting them switched around.
Mass is a form of energy. Energy is not a form of mass. Put another way, mass is always energy. Energy is not always mass.
Mass is a form of energy. Energy is not a form of mass. Put another way, mass is always energy. Energy is not always mass.
I remember some science show where they said a cup of hot water technically has slightly more mass than a cup of cold water, due to the mass contribution from the (higher/hotter) energy. Are you saying this is not the case? Would a near-absolute-zero cup of water (ice) have the same mass as a cup of boiling water?
That's always a good question!
Since we're talking about General Relativity (the top of the thread introduces the stress-energy tensor, and a particular solution to the Einstein Field Equations) let's talk in those terms. We can also talk in those terms because it is the more-fundamental theory from which Special Relativity (which gives the famous E=mc^2) can be derived.
The "stress-energy tensor" determines the curvature of spacetime. It goes by other names: the matter tensor, the energy-momentum tensor, and so forth, largely depending on how one wants to interpret the tensor components in a particular problem.
Three quick paragraphs with some reference to the mathematics:
You can write the energy-momentum tensor's components as a 4x4 matrix where each cell represents a flux of momentum from one direction to another. Momentum which "hangs around" flowing only from the past to the future corresponds to the m in "E=mc^2" either very locally or more globally in a spacetime which has no gravitation whatsoever. Since a nonzero "m" represents a nonzero value of the energy-momentum tensor, and since the energy-momentum determines the curvature of spacetime, "E=mc^2" is really just an excellent approximation that is better when m is small.
The fuller Special Relativity relation is E^2= (mc^2)^2 + (pc)^2 where we square to get rid of sign problems and where p represents linear momentum; if there is no momentum and the mass stays at the spatial origin (moving only in time) in our reference coordinates, then all but one component of the energy-momentum tensor is zero, and the one remaining one is totally determined by "m".
If we (non-gravitationally) impart momentum onto our m then p becomes nonzero and so does at least one other component of the energy-momentum tensor.
Summing up: mass sources energy-momentum, which determines curvature. Moving mass sources even more energy-momentum, and so greater curvature.
In your question about the cup, let's apply a restriction: we use the same number of water molecules at all times.
As we heat the ice or water, the motion of the water molecules relative to the centre of the coffee cup (or the overall centre-of-mass or the overall centre-of-momentum) increases. Increased motion means increased momentum. This in turn means a greater curvature is sourced by the heated molecules, or if you like, that there is a greater "active" gravitational interaction for the hot water than for the cold water or ice. "Active" in the sense of small things falling towards it. It virtually certianly also has an identically larger "passive" gravitational interaction, where "passive" is in the sense of falling towards an object that makes it seem like a very small thing. (We have excellent experimental evidence that passive and active interaction strengths are effectively identical, and the underlying theory demands it, ignoring some details about gravitational back-reaction which even experts won't want to think too hard about.)
So if we use a very sensitive scale we can measure that the hot water with exactly N molecules of hot water weighs more than the exactly N molecules of cold water. Ignoring gravitation again, we see that E is greater in the hot water case, but because there is a larger average value for p (momentum) for each of the molecules. The "m" remains effectively the same in the hot and cold water. Rest mass (m_0) is properly determined by the count of water molecules when they are completely free of momentum (including internal momentum, right down to the momentum of photons, electrons, quarks and gluons), which gives you the answer to when E is lowest for the cup of exactly N molecules of water. (It's at absolute zero!)
Back to gravitation: the minimum influence on the curvature of spacetime by the N molecules of water is when they are at absolute zero.
The difference is very tiny at the sorts of temperatures you're asking about. However, if we could somehow confine the N molecules of water into a magical box of the volume of the coffee cup, and heat the water molecules to the point where the molecular bonds break, the atoms all ionize, the oxygen nuclei disintegrate into protons, the protons disintegrate into a quark-gluon plasma, and keep going through several orders of magnitude (wherein we may discover new subatomic physics!) then as we go the "active" and "passive" gravitational interactions of the confined matter will grow substantially. It will become very heavy (passive interaction: hard to hold above the lab's floor, assuming the ultra high energy stuff didn't vapourize everything around it) and noticeably start affecting the trajectories of ever larger things (dust, pencils, lab assistants...). In the extreme, we can add so much momentum to to the stress-energy-momentum tensor the magical container encloses that it collapses into a black hole.
In essence this is what happens in the cores of neutron stars when they collapse into black holes: the internal pressure and temperature gets so high that an event horizon forms. The "container" is a few solar masses worth of incredibly dense "nuclear pasta" and other exotic stuff we don't know much about yet, and is more the size of the city the magical-container lab is in than the lab itself.
One last thing: the total value of the stress-energy tensor at a given point is observer-independent -- an ultrarelativistic observer passing by the lab and a scientist standing still in the lab will both agree on the total stress-energy-momentum of each container of water. However, different observers may prefer to split the total tensor value into its sixteen components in different ways; indeed, any single observer is free to do so because the splitting is coordinate-dependent and one is free to select from an infinite set of systems of coordinates in describing spacetime or a small patch thereof.
Because of this sort of coordinate- and observer- independence ("general covariance", technically) modern physics uses tensor fields as fundamental objects and either copes with the heavyweight mathematics that requires or reduces tensors by imposing special conditions on coordinates and on how coordinate-dependent vector-values are extracted from the tensors.
Finally, the stress-energy-momentum tensor is contributed to by all the fields of matter, so this would (where not excluded for convenience) include the classical electromagnetic tensor field, or the fields of quantum electrodynamics, or the fields of the Standard Model of particle physics. The contribution to stress-energy for known matter is always non-negative. So when considering classical or quantum matter fields, where there are nonzero field-values there is nonzero stress-energy. In heating up the water molecules we are also creating [a] more photons and [b] higher-momentum photons. Photons carry nonzero momentum and so contribute to the "p" term in E^2=(mc^2)^2+(pc)^2 or more fundamentally they add to the total tensor-value of the energy-momentum tensor.
I hope this is a helpful answer.
PS: I should have said that absolute zero is probably not physically achievable in our universe, but to the extent things can get very close to absolute zero (attokelvins or colder) we can always describe a relatively-moving observer who will think the object is warmer than someone at rest with respect to it (and some ultrarelativistic observers might think it's rather hot, spraying out a thermal bath of kilokelvin photons!). Nobody knows what the quantum chromodynamics equivalent of absolute zero would be, so that's always happening, and the momenta of the quarks and gluons thus don't completely vanish.
Since we're talking about General Relativity (the top of the thread introduces the stress-energy tensor, and a particular solution to the Einstein Field Equations) let's talk in those terms. We can also talk in those terms because it is the more-fundamental theory from which Special Relativity (which gives the famous E=mc^2) can be derived.
The "stress-energy tensor" determines the curvature of spacetime. It goes by other names: the matter tensor, the energy-momentum tensor, and so forth, largely depending on how one wants to interpret the tensor components in a particular problem.
Three quick paragraphs with some reference to the mathematics:
You can write the energy-momentum tensor's components as a 4x4 matrix where each cell represents a flux of momentum from one direction to another. Momentum which "hangs around" flowing only from the past to the future corresponds to the m in "E=mc^2" either very locally or more globally in a spacetime which has no gravitation whatsoever. Since a nonzero "m" represents a nonzero value of the energy-momentum tensor, and since the energy-momentum determines the curvature of spacetime, "E=mc^2" is really just an excellent approximation that is better when m is small.
The fuller Special Relativity relation is E^2= (mc^2)^2 + (pc)^2 where we square to get rid of sign problems and where p represents linear momentum; if there is no momentum and the mass stays at the spatial origin (moving only in time) in our reference coordinates, then all but one component of the energy-momentum tensor is zero, and the one remaining one is totally determined by "m".
If we (non-gravitationally) impart momentum onto our m then p becomes nonzero and so does at least one other component of the energy-momentum tensor.
Summing up: mass sources energy-momentum, which determines curvature. Moving mass sources even more energy-momentum, and so greater curvature.
In your question about the cup, let's apply a restriction: we use the same number of water molecules at all times.
As we heat the ice or water, the motion of the water molecules relative to the centre of the coffee cup (or the overall centre-of-mass or the overall centre-of-momentum) increases. Increased motion means increased momentum. This in turn means a greater curvature is sourced by the heated molecules, or if you like, that there is a greater "active" gravitational interaction for the hot water than for the cold water or ice. "Active" in the sense of small things falling towards it. It virtually certianly also has an identically larger "passive" gravitational interaction, where "passive" is in the sense of falling towards an object that makes it seem like a very small thing. (We have excellent experimental evidence that passive and active interaction strengths are effectively identical, and the underlying theory demands it, ignoring some details about gravitational back-reaction which even experts won't want to think too hard about.)
So if we use a very sensitive scale we can measure that the hot water with exactly N molecules of hot water weighs more than the exactly N molecules of cold water. Ignoring gravitation again, we see that E is greater in the hot water case, but because there is a larger average value for p (momentum) for each of the molecules. The "m" remains effectively the same in the hot and cold water. Rest mass (m_0) is properly determined by the count of water molecules when they are completely free of momentum (including internal momentum, right down to the momentum of photons, electrons, quarks and gluons), which gives you the answer to when E is lowest for the cup of exactly N molecules of water. (It's at absolute zero!)
Back to gravitation: the minimum influence on the curvature of spacetime by the N molecules of water is when they are at absolute zero.
The difference is very tiny at the sorts of temperatures you're asking about. However, if we could somehow confine the N molecules of water into a magical box of the volume of the coffee cup, and heat the water molecules to the point where the molecular bonds break, the atoms all ionize, the oxygen nuclei disintegrate into protons, the protons disintegrate into a quark-gluon plasma, and keep going through several orders of magnitude (wherein we may discover new subatomic physics!) then as we go the "active" and "passive" gravitational interactions of the confined matter will grow substantially. It will become very heavy (passive interaction: hard to hold above the lab's floor, assuming the ultra high energy stuff didn't vapourize everything around it) and noticeably start affecting the trajectories of ever larger things (dust, pencils, lab assistants...). In the extreme, we can add so much momentum to to the stress-energy-momentum tensor the magical container encloses that it collapses into a black hole.
In essence this is what happens in the cores of neutron stars when they collapse into black holes: the internal pressure and temperature gets so high that an event horizon forms. The "container" is a few solar masses worth of incredibly dense "nuclear pasta" and other exotic stuff we don't know much about yet, and is more the size of the city the magical-container lab is in than the lab itself.
One last thing: the total value of the stress-energy tensor at a given point is observer-independent -- an ultrarelativistic observer passing by the lab and a scientist standing still in the lab will both agree on the total stress-energy-momentum of each container of water. However, different observers may prefer to split the total tensor value into its sixteen components in different ways; indeed, any single observer is free to do so because the splitting is coordinate-dependent and one is free to select from an infinite set of systems of coordinates in describing spacetime or a small patch thereof.
Because of this sort of coordinate- and observer- independence ("general covariance", technically) modern physics uses tensor fields as fundamental objects and either copes with the heavyweight mathematics that requires or reduces tensors by imposing special conditions on coordinates and on how coordinate-dependent vector-values are extracted from the tensors.
Finally, the stress-energy-momentum tensor is contributed to by all the fields of matter, so this would (where not excluded for convenience) include the classical electromagnetic tensor field, or the fields of quantum electrodynamics, or the fields of the Standard Model of particle physics. The contribution to stress-energy for known matter is always non-negative. So when considering classical or quantum matter fields, where there are nonzero field-values there is nonzero stress-energy. In heating up the water molecules we are also creating [a] more photons and [b] higher-momentum photons. Photons carry nonzero momentum and so contribute to the "p" term in E^2=(mc^2)^2+(pc)^2 or more fundamentally they add to the total tensor-value of the energy-momentum tensor.
I hope this is a helpful answer.
PS: I should have said that absolute zero is probably not physically achievable in our universe, but to the extent things can get very close to absolute zero (attokelvins or colder) we can always describe a relatively-moving observer who will think the object is warmer than someone at rest with respect to it (and some ultrarelativistic observers might think it's rather hot, spraying out a thermal bath of kilokelvin photons!). Nobody knows what the quantum chromodynamics equivalent of absolute zero would be, so that's always happening, and the momenta of the quarks and gluons thus don't completely vanish.
As someone who isn't that familiar with the physics behind it, this comment was just as an intriguing read, if not even more than the original article. Thanks for taking the time to write an in-depth response.
> de Sitter space is a vacuum solution for Einstein's field equations.
Yes, an exact solution.
> What this means is that the stress-energy tensor is basically canceled out" everywhere by the uniform energy distribution
No, it means that the stress-energy tensor is zero at every point in the whole spacetime. There is no matter to source any curvature; the curvature is specified by the theoretician writing down the vacuum solution.
In Lorentzian 4-dimensional vacuum de Sitter spacetime ("dS" below) there is no useful concept of energy anywhere. The parameter \Lambda is incorporated directly into the Einstein curvature tensor and so is interpreted geometrically. One would have to perturb the dS vacuum in order to have a useful interpretation of \Lambda as a source of gravitational energy.
Vacuum solutions can be useful in understanding physical systems in which gravitation is important. For example, one can add non-zero stress-energy by hand and use perturbation theory to study the consequences rigorously. Alternatively, one can "cut out" parts of a vacuum solution and work with the rest which closely resembles a physical system (such as deep space far from the matter in and around galaxies). As the expansion of the universe dilutes away the matter contributing to a non-zero stress-energy tensor, our universe will resemble the sparser parts of a de Sitter spacetime. However, from our perspective (i.e. with data in our sky) there are much better approximations at various scales than de Sitter spacetime perturbed by matter fields: there is a lot of obviously non-zero stress-energy under our feet, lighting up our sky day and night, and causing heat to flow from one place to another.
> That means no gravity
There can be extremely strong spacetime curvature in de Sitter space!
In general we can time-orient dS: in one direction objects which only interact gravitationally and do not generate significant stress-energy will always converge, in the other they will always diverge, depending on the value of the \Lambda parameter, which is always positive for dS. If \Lambda is large, all such objects leave the others' causal cones much more quickly than they could, even in principle, in flat spacetime.
If we perturb dS with a dense ball of nonrelativistic (i.e., slowly-moving) dust that feels only the gravitational interaction, the dust will tend to collapse if \Lambda is sufficiently small, and will locally approximate a Lemaître-Tolman-Bondi (LTB) collapsing dust metric, which in turn resembles a perturbation of vacuum Schwarzschild or Kerr (which are eternal black hole models; there is no matter to collapse).
A scattering of such collapsing dust-balls with significant gaps between them has been studied by a number of relativists as a family of "swiss-cheese" cosmologies very similar to the one developed by Einstein & Strauss in 1945, who represented the balls of dust as already-collapsed vacuum Schwarzschild solutions, calling them "holes" in the "cheese" of the surrounding expanding spacetime. The Einstein-Strauss-de Sitter model approximated some features of our universe at intermediate ranges, but has since been superseded by the the Friedmann-Lemaître-Robertson-Walker (FLRW) model of the modern standard model of cosmology that among other things has representations of nonzero stress-energy that the vacuum Einstein & Strauss model did not, and which better matches observables in our sky than models that added more realistic matter fields to Einstein & Strauss vacuum.
One feature of Einstein-Strauss-de Sitter style expanding swiss-cheese models is that a small "test" amount of sparse low-mass nonrelativistic dust scattered in the LTB "holes" will stay confined within the hole while the hole separates from everything else. However, an identical test dust scattered in the "cheese" part well outside of holes will never find its way into a hole. Ultimately the former test dust will converge while the latter will diverge.
We can get highly similar results by perturbing the FLRW model. (The observable universe is well approximated by an almost FLRW model in which there are primordial density fluctuations: over-dense areas collapse gravitationally, comparably to the matter in the "holes" of a non-vacuum Einstein-Strauss-de Sitter universe.)
Locally in all these cases, what we have are the tensor fields contributing to the Einstein Field Equations, and general covariance. We can talk about the values of these tensors at any given point (and its neighbourhood), but General Relativity does not lend itself to universal definitions of energy or even energy-density. We can reduce the tensors by using gauge fixing and other techniques, and "demote" the cosmological constant in FLRW or in dS into an energy. (That's really all Dark Energy is in the standard cosmology). In such a gauge we can talk about the work matter interactions (e.g. the electromagnetic interaction) does "against" dark energy. However, the real physics are in the tensors, and applying coordinates and selecting particular observers, while often able to make things much easier to calculate, can be highly misleading too.
The idea that the cosmological constant is "cancelled" out by matter-matter gravitational interactions (and electromagnetic and nuclear interactions) is a statement that the geometrical nature of the cosmological constant is "demoted" into an extremely weak force field, and leads to all sorts of statements that work in that "demotion" context but not generally. Typical statements are that the solar system is expanding, or the galaxy or cluster is expanding, because of the tiny local force on matter by dark energy.
It is better to retreat to "swiss-cheese" and say that the geometry of our solar system is not well-approximated by expanding metrics like dS or expanding Robertson-Walker, and that consequently it is a better fit to observations that in our "hole" (which the matter of our solar system, galaxy and cluster sources) the cosmological constant simply vanishes.
Better still would be to advance to inhomogeneous metrics, but those are a subject of research beyond the scope of this comment.
Finally, your last paragraph can also be read as a request to be directed to the concept of the Jeans Instability in the Expanding Universe. If in the very early universe there was truly uniform and dense distribution of stress-energy, the slightest perturbations would magnify, leading to structure formation. As I wrote above primordial fluctuations of an otherwise FLRW model approximates modern cosmological observations very well. (One could alternatively introduce dissipation, quantum uncertainties, and so forth, as a source of gravitational Jeans Instability causing the collapse or fragmentation of a uniform distribution of stress-energy).
Yes, an exact solution.
> What this means is that the stress-energy tensor is basically canceled out" everywhere by the uniform energy distribution
No, it means that the stress-energy tensor is zero at every point in the whole spacetime. There is no matter to source any curvature; the curvature is specified by the theoretician writing down the vacuum solution.
In Lorentzian 4-dimensional vacuum de Sitter spacetime ("dS" below) there is no useful concept of energy anywhere. The parameter \Lambda is incorporated directly into the Einstein curvature tensor and so is interpreted geometrically. One would have to perturb the dS vacuum in order to have a useful interpretation of \Lambda as a source of gravitational energy.
Vacuum solutions can be useful in understanding physical systems in which gravitation is important. For example, one can add non-zero stress-energy by hand and use perturbation theory to study the consequences rigorously. Alternatively, one can "cut out" parts of a vacuum solution and work with the rest which closely resembles a physical system (such as deep space far from the matter in and around galaxies). As the expansion of the universe dilutes away the matter contributing to a non-zero stress-energy tensor, our universe will resemble the sparser parts of a de Sitter spacetime. However, from our perspective (i.e. with data in our sky) there are much better approximations at various scales than de Sitter spacetime perturbed by matter fields: there is a lot of obviously non-zero stress-energy under our feet, lighting up our sky day and night, and causing heat to flow from one place to another.
> That means no gravity
There can be extremely strong spacetime curvature in de Sitter space!
In general we can time-orient dS: in one direction objects which only interact gravitationally and do not generate significant stress-energy will always converge, in the other they will always diverge, depending on the value of the \Lambda parameter, which is always positive for dS. If \Lambda is large, all such objects leave the others' causal cones much more quickly than they could, even in principle, in flat spacetime.
If we perturb dS with a dense ball of nonrelativistic (i.e., slowly-moving) dust that feels only the gravitational interaction, the dust will tend to collapse if \Lambda is sufficiently small, and will locally approximate a Lemaître-Tolman-Bondi (LTB) collapsing dust metric, which in turn resembles a perturbation of vacuum Schwarzschild or Kerr (which are eternal black hole models; there is no matter to collapse).
A scattering of such collapsing dust-balls with significant gaps between them has been studied by a number of relativists as a family of "swiss-cheese" cosmologies very similar to the one developed by Einstein & Strauss in 1945, who represented the balls of dust as already-collapsed vacuum Schwarzschild solutions, calling them "holes" in the "cheese" of the surrounding expanding spacetime. The Einstein-Strauss-de Sitter model approximated some features of our universe at intermediate ranges, but has since been superseded by the the Friedmann-Lemaître-Robertson-Walker (FLRW) model of the modern standard model of cosmology that among other things has representations of nonzero stress-energy that the vacuum Einstein & Strauss model did not, and which better matches observables in our sky than models that added more realistic matter fields to Einstein & Strauss vacuum.
One feature of Einstein-Strauss-de Sitter style expanding swiss-cheese models is that a small "test" amount of sparse low-mass nonrelativistic dust scattered in the LTB "holes" will stay confined within the hole while the hole separates from everything else. However, an identical test dust scattered in the "cheese" part well outside of holes will never find its way into a hole. Ultimately the former test dust will converge while the latter will diverge.
We can get highly similar results by perturbing the FLRW model. (The observable universe is well approximated by an almost FLRW model in which there are primordial density fluctuations: over-dense areas collapse gravitationally, comparably to the matter in the "holes" of a non-vacuum Einstein-Strauss-de Sitter universe.)
Locally in all these cases, what we have are the tensor fields contributing to the Einstein Field Equations, and general covariance. We can talk about the values of these tensors at any given point (and its neighbourhood), but General Relativity does not lend itself to universal definitions of energy or even energy-density. We can reduce the tensors by using gauge fixing and other techniques, and "demote" the cosmological constant in FLRW or in dS into an energy. (That's really all Dark Energy is in the standard cosmology). In such a gauge we can talk about the work matter interactions (e.g. the electromagnetic interaction) does "against" dark energy. However, the real physics are in the tensors, and applying coordinates and selecting particular observers, while often able to make things much easier to calculate, can be highly misleading too.
The idea that the cosmological constant is "cancelled" out by matter-matter gravitational interactions (and electromagnetic and nuclear interactions) is a statement that the geometrical nature of the cosmological constant is "demoted" into an extremely weak force field, and leads to all sorts of statements that work in that "demotion" context but not generally. Typical statements are that the solar system is expanding, or the galaxy or cluster is expanding, because of the tiny local force on matter by dark energy.
It is better to retreat to "swiss-cheese" and say that the geometry of our solar system is not well-approximated by expanding metrics like dS or expanding Robertson-Walker, and that consequently it is a better fit to observations that in our "hole" (which the matter of our solar system, galaxy and cluster sources) the cosmological constant simply vanishes.
Better still would be to advance to inhomogeneous metrics, but those are a subject of research beyond the scope of this comment.
Finally, your last paragraph can also be read as a request to be directed to the concept of the Jeans Instability in the Expanding Universe. If in the very early universe there was truly uniform and dense distribution of stress-energy, the slightest perturbations would magnify, leading to structure formation. As I wrote above primordial fluctuations of an otherwise FLRW model approximates modern cosmological observations very well. (One could alternatively introduce dissipation, quantum uncertainties, and so forth, as a source of gravitational Jeans Instability causing the collapse or fragmentation of a uniform distribution of stress-energy).
I'm not an expert, but I don't think that quote is quite right. There is still a notion of time, there is just no notion of a direction of time. For example, if you go deep into empty space, then one patch of space looks just like the next one. That doesn't mean there is no longer a physical concept of space. Similarly, just because one point in time doesn't look very different from the next, doesn't mean that there isn't a notion of time.
The main point of thermodynamic time is to describe the idea that time appears to be moving forward. According to fundamental physics, as far as we can tell, time is symmetric (with a few caveats). So going forward in time should look similar to going backwards in time, just like going to the left in deep space is the same as going to the right. But the fact that we are in a pocket of high entropy means that time has an apparent direction.
The main point of thermodynamic time is to describe the idea that time appears to be moving forward. According to fundamental physics, as far as we can tell, time is symmetric (with a few caveats). So going forward in time should look similar to going backwards in time, just like going to the left in deep space is the same as going to the right. But the fact that we are in a pocket of high entropy means that time has an apparent direction.
Speaking of this, does anyone know of an explanation for why the direction in spacetime in which entropy decreases is parallel to the time dimension (the one with a different sign in the relativistic metric) of spacetime?
Maybe I'm missing something, but I've never seen a link made between the two.
Maybe I'm missing something, but I've never seen a link made between the two.
As opposed to entropy decreasing as you travel, say, toward the galactic north? It's a good question. One answer could be the mostly spatially uniform initial conditions of the big bang.
Also, a spatial entropy gradient would gradually diffuse over time to become uniform again.
But in general, the arrow of time is a consequence of systems that store a memory of their pasts, which is possible because the past is lower entropy than the future. (The past can be more accurately predicted by querying the state of the data in memory than the future can). You could probably set up a carefully designed system with a spatial entropy gradient, and somehow get a memory where the arrangement of atoms on the left always "remembers" the arrangement of atoms on the right, but not the other way around. Maybe there are even systems like this found in nature? Interesting to think about.
Also, a spatial entropy gradient would gradually diffuse over time to become uniform again.
But in general, the arrow of time is a consequence of systems that store a memory of their pasts, which is possible because the past is lower entropy than the future. (The past can be more accurately predicted by querying the state of the data in memory than the future can). You could probably set up a carefully designed system with a spatial entropy gradient, and somehow get a memory where the arrangement of atoms on the left always "remembers" the arrangement of atoms on the right, but not the other way around. Maybe there are even systems like this found in nature? Interesting to think about.
Thanks for the answer. I mean exactly that! Thoughts on your thoughts:
> One answer could be the mostly spatially uniform initial conditions of the big bang.
That's fair, but in that case, to continue the galactic north analogy, is there a reason why the Big Bang couldn't have happened uniformly in the dimension-3 hyperplane of (time, plane of the milky way) instead of the space hyperplane?
> a spatial entropy gradient would gradually diffuse over time to become uniform again.
But wouldn't that be "diffuse over direction-of-decreasing entropy time", not "diffuse over relativistic-time-dimension time"? In that case, I don't think it would help.
Apologies if I'm missing your points or not making sense, I can't claim I understand any of this well. I just feel like I see a lot of circular arguments around this :).
> One answer could be the mostly spatially uniform initial conditions of the big bang.
That's fair, but in that case, to continue the galactic north analogy, is there a reason why the Big Bang couldn't have happened uniformly in the dimension-3 hyperplane of (time, plane of the milky way) instead of the space hyperplane?
> a spatial entropy gradient would gradually diffuse over time to become uniform again.
But wouldn't that be "diffuse over direction-of-decreasing entropy time", not "diffuse over relativistic-time-dimension time"? In that case, I don't think it would help.
Apologies if I'm missing your points or not making sense, I can't claim I understand any of this well. I just feel like I see a lot of circular arguments around this :).
> is there a reason why the Big Bang couldn't have happened uniformly in the dimension-3 hyperplane
It's a really good question. I think it has to do with how space expanded after the big bang (which is to me still a mysterious subject).
To avoid confusion, let me call "time" the arrow of time as perceived from within a system, and "TIME" the coordinate axis of spacetime that has the opposite sign from the other three.
The early days of the universe were full of heat and radiation everywhere throughout space, which seems like a high entropy scenario for sure. But entropy was able to increase as the universe cooled because space itself expanded adiabatically (and so the configuration space became larger).
In other words, we end up with an entropy gradient that points along the TIME axis because the volume of space expands along that axis. Like space-time is shaped like a pyramid rather than a cube, with the pointy axis in the TIME direction.
I don't know enough general relativity to say for sure, but I expect that that pyramid shape (expanding towards later times) is probably a consequence of TIME behaving differently than other spatial dimensions. If spacetime shrank volumetrically toward the galactic north, in a fairly uniform way throughout all times and throughout the universe, then we'd have a different conclusion. (This might seem like the case near a black hole).
I guess another thing to remember is that TIME and space really are different things. For example, conservation of angular momentum means the universe has constant angular momentum at all times, but not necessarily in all directions of space.
It's a really good question. I think it has to do with how space expanded after the big bang (which is to me still a mysterious subject).
To avoid confusion, let me call "time" the arrow of time as perceived from within a system, and "TIME" the coordinate axis of spacetime that has the opposite sign from the other three.
The early days of the universe were full of heat and radiation everywhere throughout space, which seems like a high entropy scenario for sure. But entropy was able to increase as the universe cooled because space itself expanded adiabatically (and so the configuration space became larger).
In other words, we end up with an entropy gradient that points along the TIME axis because the volume of space expands along that axis. Like space-time is shaped like a pyramid rather than a cube, with the pointy axis in the TIME direction.
I don't know enough general relativity to say for sure, but I expect that that pyramid shape (expanding towards later times) is probably a consequence of TIME behaving differently than other spatial dimensions. If spacetime shrank volumetrically toward the galactic north, in a fairly uniform way throughout all times and throughout the universe, then we'd have a different conclusion. (This might seem like the case near a black hole).
I guess another thing to remember is that TIME and space really are different things. For example, conservation of angular momentum means the universe has constant angular momentum at all times, but not necessarily in all directions of space.
> In other words, we end up with an entropy gradient that points along the TIME axis because the volume of space expands along that axis.
That's a good insight, I hadn't thought of it that way.
> I guess another thing to remember is that TIME and space really are different things. For example, conservation of angular momentum means the universe has constant angular momentum at all times, but not necessarily in all directions of space.
Yes, I realize they are different, but I feel like the issue is more that don't understand the relationship between the special properties of TIME and those of time.
That's a good insight, I hadn't thought of it that way.
> I guess another thing to remember is that TIME and space really are different things. For example, conservation of angular momentum means the universe has constant angular momentum at all times, but not necessarily in all directions of space.
Yes, I realize they are different, but I feel like the issue is more that don't understand the relationship between the special properties of TIME and those of time.
I'm not sure, and this is a lot of speculation, but I feel like it has to do with the fact that mass/energy is conserved over time (but not in space) [1]. The mass now corresponds to the mass in the past/future, which, for example, allows memories to form. In any case, time is still a qualitatively different dimension than space.
[1] https://en.m.wikipedia.org/wiki/Conservation_law#Exact_laws
[1] https://en.m.wikipedia.org/wiki/Conservation_law#Exact_laws
Low entropy systems are likely to transition into high entropy systems, and the reverse is unlikely to occur. It is largely a statistical argument; low entropy states are by definition less likely to occur by chance than high entropy states.
(You might then ask why we care what happens 'by chance'; the answer is either that physics is fundamentally unpredictable, or that the scale of the universe so large that the influence of the whole on any particular subsystem must necessarily be modeled with noise.)
(You might then ask why we care what happens 'by chance'; the answer is either that physics is fundamentally unpredictable, or that the scale of the universe so large that the influence of the whole on any particular subsystem must necessarily be modeled with noise.)
We are in a pocket of high order/ low entropy (not high entropy).
That's what I meant -- thanks for the catch!
Here is the crux. Time IS motion. We measure this motion of objects relative to one another by comparing their motion to a standard set of things in motion called a clock. There is nothing else to time except that; but it is real, as real as anything, it is not an illusion.
> Time IS motion.
Relatively speaking, yes.
> There is nothing else to time except that; but it is real, as real as anything, it is not an illusion.
The article isn't claiming time is an illusion, only our perception of it flowing.
Relatively speaking, yes.
> There is nothing else to time except that; but it is real, as real as anything, it is not an illusion.
The article isn't claiming time is an illusion, only our perception of it flowing.
Yes, it is the sense of time moving that is an illusion; Time itself is a fact, and can be measured.
> [time] is real, as real as anything, it is not an illusion.
Now the arrow of time on the other hand...
Now the arrow of time on the other hand...
No clocks, no time, right?
This is strangely approaching Nietzsche's notion of Eternal Return of the Same with the caveat that he additionally speculated that if particles and their configurations are finite, then moments in lived experience necessarily repeat themselves "at some point". This to him was the most gargantuan challenge to the Christian moral tradition since this eliminates any notion of Providence as well as the more general moral notion of "You could've done otherwise" since there's no value to considering timelines, not even from a "Best Possible World of All Worlds" sense.
>that if particles and their configurations are finite, then moments in lived experience necessarily repeat themselves
I don't know much about Nietzsche, but this statement does not seem correct. One can have infinite configurations of a finite number of particles. The only way a finite number of particles would imply finite configurations would be (a) space is finite, and (b) space is not continuous. That is, if you imagine the universe as composed of discrete slots in which particles must exist, and the number of slots is finite, then his idea makes sense. But, is there a reason to think this?
I don't know much about Nietzsche, but this statement does not seem correct. One can have infinite configurations of a finite number of particles. The only way a finite number of particles would imply finite configurations would be (a) space is finite, and (b) space is not continuous. That is, if you imagine the universe as composed of discrete slots in which particles must exist, and the number of slots is finite, then his idea makes sense. But, is there a reason to think this?
That quote also shows how difficult it is to even discuss the idea without invoking the notion of a flow from a past to a future.
Science provides both a way of calculating what is going on, and also, apparently, explanations (up to the limits of our knowledge) for what happens. To eliminate the notion of time's flow from discussions of physics, would we have to abandon the concept of causality from our explanations?
Science provides both a way of calculating what is going on, and also, apparently, explanations (up to the limits of our knowledge) for what happens. To eliminate the notion of time's flow from discussions of physics, would we have to abandon the concept of causality from our explanations?
Yes, causality is one of the ways of defining Time.
https://en.m.wikipedia.org/wiki/Arrow_of_time
https://en.m.wikipedia.org/wiki/Arrow_of_time
That same quote confuses me. If there are no events to measure time, why does that mean that time stopped? Can't it keep flowing just as space keeps expanding regardless of measurement? More so, photon decay is not completely ruled out yet, so events could keep happening in that cold photon bath.
It has to do with what time means. A coloiquial understanding of time has almost everything to with the way our mind and our memories work.
Our mind and memories won't be of much use at the end of the universe, so we have to depend on a more scientific definition. The best scientific way of describing and measuring time outside of our minds basically comes down to measuring systems as they increase entropy. As the universe ages, and these systems approach maximum entropy, the ability to measure time, and the ability to describe in any concrete way what time means, becomes increasingly difficult.
Our mind and memories won't be of much use at the end of the universe, so we have to depend on a more scientific definition. The best scientific way of describing and measuring time outside of our minds basically comes down to measuring systems as they increase entropy. As the universe ages, and these systems approach maximum entropy, the ability to measure time, and the ability to describe in any concrete way what time means, becomes increasingly difficult.
> I am not a cosmologist, but if all of space reached thermal equilibrium, if space does have any mass (perhaps a tiny amount from the dark energy it contains?), and the entire universe is essentially one uniform mass, wouldn't that mass then collapse upon itself, in a kind of big bounce?
Nor am I, but as long as the universe keeps expanding and everything keeps flying apart the average density will probably continue to decrease and gravity will be too weak to cause a collapse.
Or are you saying dark energy (intrinsic to space itself) would eventually dominate and concentrate?
Nor am I, but as long as the universe keeps expanding and everything keeps flying apart the average density will probably continue to decrease and gravity will be too weak to cause a collapse.
Or are you saying dark energy (intrinsic to space itself) would eventually dominate and concentrate?
Dark energy would simply accelerate the asymptotic approach to equilibrium by spreading everything out. When everything is evenly spread out and in thermal equilibrium, the aggregate effect of gravity could take over, if the mass/energy of the universe was truly uniformly distributed. Or this is my armchair/idiot idea anyway.
> there will be no sense of time anymore [...] This is the way the world ends
If there is no sense of time why does the world "end"?
> If that is true, then time never really ends, it just "slows down" a lot (not much can happen, and not terribly quickly) until the next sparkup, whereupon time speeds up dramatically (inflationary theory).
Time slowing down or speeding up is still a "sense of time". Moreover time slowing down or speeding up is a human perception, and not a fact of the universe.
If there is no sense of time why does the world "end"?
> If that is true, then time never really ends, it just "slows down" a lot (not much can happen, and not terribly quickly) until the next sparkup, whereupon time speeds up dramatically (inflationary theory).
Time slowing down or speeding up is still a "sense of time". Moreover time slowing down or speeding up is a human perception, and not a fact of the universe.
I think it’s quite the stretch.
By the same token, if I let my coffee thermo reach thermal equilibrium and don’t touch it, can I claim I’ve built a machine that stops time?
By the same token, if I let my coffee thermo reach thermal equilibrium and don’t touch it, can I claim I’ve built a machine that stops time?
No, the rest of the universe could still effect that coffee externally. A universe at thermal equilibrium would encompass everything (which naturally also means there could not be anyone or anything around to measure anything either)
There is a fascinating video that I saw a couple of years ago about conformal cyclic cosmology.
https://youtu.be/sM47acQ7pEQ
I heard something about this theory as a whole falling out of favor, but many of the ideas presented are terribly interesting.
https://youtu.be/sM47acQ7pEQ
I heard something about this theory as a whole falling out of favor, but many of the ideas presented are terribly interesting.
Read The Last Question if you haven't
I love that story, alas it doesn't give me any additional insight on these questions.
Plus, the state of the art has progressed much since then. I'm curious what the latest science says about when the universe is only empty space in thermal equilibrium, would the space itself have any mass, and would that mass be self-attractive? Would there be an even distribution of particles that don't decay (proton?), or if all particles decay, then an even distribution of energy, which also has mass?
Plus, the state of the art has progressed much since then. I'm curious what the latest science says about when the universe is only empty space in thermal equilibrium, would the space itself have any mass, and would that mass be self-attractive? Would there be an even distribution of particles that don't decay (proton?), or if all particles decay, then an even distribution of energy, which also has mass?
Dark energy does not attract. Also enjoy these:
* https://news.ycombinator.com/item?id=18609375
* https://news.ycombinator.com/item?id=18628072
* https://news.ycombinator.com/item?id=18609375
* https://news.ycombinator.com/item?id=18628072
And watch this: Timelapse of the future - A Journey to the End of Time: https://www.youtube.com/watch?v=uD4izuDMUQA
> Physicists increasingly suspect that there may be multiple universes beyond our own, each with their own unique laws of physics.
Yeah, it's a bit too dramatized and speculative at the end.
Imagine a ball rolling down a huge basin. Very deep, ball gets a terminal velocity, rolls down at constant speed. Then the basin shallows, and finally the ball reaches the bottom. From the ball's point of view, "downnwardness", an ineluctable constant, has ceased to exist.
When his great Italian friend Michele Besso died, Einstein wrote a moving letter to Michele’s sister: ‘Michele has left this strange world a little before me. This means nothing. People like us, who believe in physics, know that the distinction made between past, present and future is nothing more than a persistent, stubborn illusion.’
... ...
Many times in the past we have realized that it is our immediate intuitions that are imprecise: if we had kept to these we would still believe that the Earth is flat and that it is orbited by the sun.
Our intuitions have developed on the basis of our limited experience. When we look a little further ahead we discover that the world is not as it appears to us: the Earth is round, and in Cape Town their feet are up and their heads are down.
To trust immediate intuitions rather than collective examination that is rational, careful and intelligent is not wisdom: it is the presumption of an old man who refuses to believe that the great world outside his village is any different from the one which he has always known.
-- Seven Brief Lessons on Physics, Carlo Rovelli
... ...
Many times in the past we have realized that it is our immediate intuitions that are imprecise: if we had kept to these we would still believe that the Earth is flat and that it is orbited by the sun.
Our intuitions have developed on the basis of our limited experience. When we look a little further ahead we discover that the world is not as it appears to us: the Earth is round, and in Cape Town their feet are up and their heads are down.
To trust immediate intuitions rather than collective examination that is rational, careful and intelligent is not wisdom: it is the presumption of an old man who refuses to believe that the great world outside his village is any different from the one which he has always known.
-- Seven Brief Lessons on Physics, Carlo Rovelli
"Dr. Manhattan: There is no future. There is no past. Do you see? Time is simultaneous, an intricately structured jewel that humans insist on viewing one edge at a time, when the whole design is visible in every facet." -Alan Moore, Watchmen
To me, this idea looks like we have a set of measurements of things (X, Y, Z, T) and a function F that maps from the set of measurements to a future set of measurements. You can generate the future from the past. You could take the view that all these measurements exist, and we just can't see them (well) because we are only able to jump from Tnow to F(Tnow). In other words, we exist in one place and one time at a time.
To me, this idea looks like we have a set of measurements of things (X, Y, Z, T) and a function F that maps from the set of measurements to a future set of measurements. You can generate the future from the past. You could take the view that all these measurements exist, and we just can't see them (well) because we are only able to jump from Tnow to F(Tnow). In other words, we exist in one place and one time at a time.
I was really impressed by this 4d toys video: https://youtu.be/0t4aKJuKP0Q
Now what if time is an illusion and similar to the video objects in life simply appear to be bouncing in and out of our 3d realm? That would look a lot like time.
But if we could see in 4d, we'd see that they're not really coming or going and could see all of their possible states at once.
It might be like being able to see an entire movie all at once rather than frame by frame.
Now what if time is an illusion and similar to the video objects in life simply appear to be bouncing in and out of our 3d realm? That would look a lot like time.
But if we could see in 4d, we'd see that they're not really coming or going and could see all of their possible states at once.
It might be like being able to see an entire movie all at once rather than frame by frame.
The Order of Time by Carlo Rovelli (https://www.amazon.com/Order-Time-Carlo-Rovelli/dp/073521610...) is an amazing and eye opening book on the topic of time. Carlo, a theoretical physicist who specializes in quantum gravity, slowly peels back the layers of the conceptual onion to get to some pretty strange fundamental truths about time.
As a side note, the Audible book is read by Benedict Cumberbach and is a delightful listen.
As a side note, the Audible book is read by Benedict Cumberbach and is a delightful listen.
This book is a MUST READ imho. I heard him pitching the book on KQED Forum, he seems quite a pleasant, amiable fellow.
Books like this deserve a re-read at least once. Now I know to do the audible for round 2 in a few years.
Books like this deserve a re-read at least once. Now I know to do the audible for round 2 in a few years.
The World Science Festival has a slew of episodes on the flow and illusion of time: https://www.youtube.com/user/worldsciencefestival/search?que...
One of the thoughts I've been having recently about "human time" is the effect that the observance of changing seasons and the circle of life over an evolutionary period has had on how humans think about things like time and permanence. Unfortunately I don't have anything particularly insightful to say other than I've been wondering about it. ¯\_(ツ)_/¯
One of the thoughts I've been having recently about "human time" is the effect that the observance of changing seasons and the circle of life over an evolutionary period has had on how humans think about things like time and permanence. Unfortunately I don't have anything particularly insightful to say other than I've been wondering about it. ¯\_(ツ)_/¯
The word 'illusion' should be removed from every dictionary. It's one completely unspecific, indeterminate and misleading word and most subjects or patterns of discourse in which it appears have the same properties.
The title of this post also reminds me of https://en.wikipedia.org/wiki/E-Prime
Just searching for "* is an illusion" returns
- consciousness - choice - spacetime - the world - physical reality - certainty - memories
It makes me feel disgusted.
The title of this post also reminds me of https://en.wikipedia.org/wiki/E-Prime
Just searching for "* is an illusion" returns
- consciousness - choice - spacetime - the world - physical reality - certainty - memories
It makes me feel disgusted.
The word is used to describe large and unknowable concepts as well as optical tricks?
Its possible for a word to have more than one meaning.
Its possible for a word to have more than one meaning.
illusion - noun, an instance of a wrong or misinterpreted perception of a sensory experience.
A misinterpretation always requires a context, or direction. Its use implies the existence of a 'true interpretation'. The word illusion doesn't give either, it just signifies that there is one. But then I have to ask, how can a subjective experience be something truly or falsely interpreted?
There's all sorts of optical illusions. If you're seeing a color that isn't in the image, then your subjective experience is that of an illusion. Perceptual illusions are where the term originates.
> The title of this post also reminds me of https://en.wikipedia.org/wiki/E-Prime
I don't understand what the title has to do with avoiding forms of "to be"? It contains the word "is".
I don't understand what the title has to do with avoiding forms of "to be"? It contains the word "is".
"Is" is (heh) one of the forms of "to be" and can signify many different things: https://en.wikipedia.org/wiki/E-Prime#Different_functions_of...
"Illusion" is perfectly well defined: it is a perception that does not correspond to any objective reality outside your brain.
No, that's the definition of a hallucination. Illusions are misinterpretation's of objective reality by the brain (and I agree that's not a well-defined thing).
The problem is, that just punts the issue down to what is considered objective reality. If that's in contention, as in this specific case, then referring to things as illusory can be ambiguous. I happen to disagree with the comment you are responding to, but I do accept that the term illusion is often used ambiguously, especially in relation to notions of objective and subjective reality.
Yes, that's true, but it's not because "illusion" is not well-defined. It is, and claiming that time is an illusion is a perfectly coherent claim. It might be a controversial claim, and its truth might be difficult to resolve. But it's not ill-posed.
Yeah, but illusion was one of the foundations upon which philosophy got started. People noticed that things were not always as they seemed, and this started a lot of questioning about the nature of things, perception and the mind.
On it's own in a sentence perhaps yes, but in the context of an in-depth interview in which the author explains exactly what they mean by it I think it's ok. We just need to be aware that many of the words we use can have a variety of meanings, but once that meaning is clear it's useful to be able to continue using the words on their own.
An illusion is simply a state where the model of the world created by the mind differs from the world as it exists.
In a pedantic sense, it’s all an illusion, but there are particular illusions where the difference is readily demonstrable — when the magician shows what was hidden in his sleeves, as it were.
In some sense, most of science is exposing the method of various tricks our own consciousness plays on us. We want to know, for example, why metal appears to be shiny— when the phenomenon we’re studying ‘shininess’ only exists in our own minds. There’s no innate ‘shiny’ property in nature.
Time is one of those things where there is a persistent feeling that it must be illusory (which is to say, something created by our minds), but we’re not quite sure exactly in what way or how to prove it.
In a pedantic sense, it’s all an illusion, but there are particular illusions where the difference is readily demonstrable — when the magician shows what was hidden in his sleeves, as it were.
In some sense, most of science is exposing the method of various tricks our own consciousness plays on us. We want to know, for example, why metal appears to be shiny— when the phenomenon we’re studying ‘shininess’ only exists in our own minds. There’s no innate ‘shiny’ property in nature.
Time is one of those things where there is a persistent feeling that it must be illusory (which is to say, something created by our minds), but we’re not quite sure exactly in what way or how to prove it.
Illusion can be tricky to understand, but not impossible. It means that the referent is not the same as the representation. When something isn't an illusion, it means the referent is the same as the representation. We have different words for different kinds of illusion. I can show you an actual, physical chair, or a picture of a chair. The first is not an illusion, while the second is.
You watch a real television show on a real television. The television is designed to create visual illusions of real things. But the television is itself real. The show is a dramatic rendering, an illusion, of real-life situations.
So there's three elements needed to make illusion. A referent, a representation, and a type.
Consciousness is real, but its contents are illusory, thought represents things that are not those things.
You watch a real television show on a real television. The television is designed to create visual illusions of real things. But the television is itself real. The show is a dramatic rendering, an illusion, of real-life situations.
So there's three elements needed to make illusion. A referent, a representation, and a type.
Consciousness is real, but its contents are illusory, thought represents things that are not those things.
> I can show you an actual, physical chair, or a picture of a chair. The first is not an illusion, while the second is.
If the picture of the chair is so good that one mistakes it for a real chair, yes, otherwise I wouldn’t classify it as an illusion.
On a tangential note, people enjoying this discussion might enjoy the beginning of chapter two[1] (or even the whole book) of Scott McCloud’s “Understanding Comics”[2].
[1]: https://rhetoricsuperhero.files.wordpress.com/2013/09/mcclou...
[2]: https://en.wikipedia.org/wiki/Understanding_Comics
If the picture of the chair is so good that one mistakes it for a real chair, yes, otherwise I wouldn’t classify it as an illusion.
On a tangential note, people enjoying this discussion might enjoy the beginning of chapter two[1] (or even the whole book) of Scott McCloud’s “Understanding Comics”[2].
[1]: https://rhetoricsuperhero.files.wordpress.com/2013/09/mcclou...
[2]: https://en.wikipedia.org/wiki/Understanding_Comics
An enlightened yogi, Hindi, or Buddhist would say that the physical chair is also an illusion.
Enlightened yogis can misunderstand the concept just as easily as Westerners.
Why, do you think? Because they reasoned that in the mind, everything can refer to anything else?
Enlightenment is the destruction of the perception that there is a separate watcher apart from the watched. Non-duality. Not-two. Just one. Since illusion requires three elements, the non-dual is just one element, there is no illusion.
Any time you step 'outside', like if you look at a chair, you're dwelling in illusion. Mind generated a 'tag' for the thing you're seeing. It's not really a chair, it's a bundle of atoms. But there's no bundle of atoms, that's also a tag generated by mind. The mind itself isn't what you think it is. Everything is an illusion.
Tricky to understand until you realize there's no such thing as enlightenment, it's just a religious dogma. Enlightened yogis are no different than the rest of us.
One can train the mind to perceive fewer distinctions, this is yogic practice. You can even arrive at a state of mind that you can call enlightenment. But the lie is revealed any time you open your mouth. The state of mind that is being trained is an illusion like everything else.
Real yogis understand this and do it anyway. Fake yogis try to fool you into believing that you can truly get rid of everything and 'merely exist'. It's not an illusion at this point, it's a lie.
Any time you step 'outside', like if you look at a chair, you're dwelling in illusion. Mind generated a 'tag' for the thing you're seeing. It's not really a chair, it's a bundle of atoms. But there's no bundle of atoms, that's also a tag generated by mind. The mind itself isn't what you think it is. Everything is an illusion.
Tricky to understand until you realize there's no such thing as enlightenment, it's just a religious dogma. Enlightened yogis are no different than the rest of us.
One can train the mind to perceive fewer distinctions, this is yogic practice. You can even arrive at a state of mind that you can call enlightenment. But the lie is revealed any time you open your mouth. The state of mind that is being trained is an illusion like everything else.
Real yogis understand this and do it anyway. Fake yogis try to fool you into believing that you can truly get rid of everything and 'merely exist'. It's not an illusion at this point, it's a lie.
What would magicians do without illusions, mere tricks, that's what. Shame on you.
The association of the word with mystery in particular doesn't help to bring clarity in discussions with a scientific context. If I said "semiconductors are an illusion", "programming is an illusion" etc. it doesn't contribute any information. It just confuses.
But if one said magicians use sleight of hand to fool the brains of audience members into the illusion that magic has been performed, then why doesn't that bring clarity? Illusions are perceptual errors the brain creates when misinterpreting data from the senses, often because of some unusual condition in the environment.
This idea has been extended to say things like reality could be an illusion (Matrix scenarios), or something we take to be fundamental to reality such as the flow of time could be an illusion, in that our mental experience of it is misleading us into thinking it's fundamental.
That we can be fooled by our experience of the world is not controversial. People thought the world was flat and that the moon and sun rose around a still Earth, which was the center of the cosmos. Because that's how it appeared to them.
This idea has been extended to say things like reality could be an illusion (Matrix scenarios), or something we take to be fundamental to reality such as the flow of time could be an illusion, in that our mental experience of it is misleading us into thinking it's fundamental.
That we can be fooled by our experience of the world is not controversial. People thought the world was flat and that the moon and sun rose around a still Earth, which was the center of the cosmos. Because that's how it appeared to them.
The map is not the territory.
To say something is an illusion means that something is a map that doesn’t match the territory.
But it assumes there IS a territory to map! While often simultaneously denying its existence. That’s the contradiction.
To say something is an illusion means that something is a map that doesn’t match the territory.
But it assumes there IS a territory to map! While often simultaneously denying its existence. That’s the contradiction.
Words aren't used because they are in the dictionary, they are in the dictionary because they are used.
Whatever time is, our favorite way to 'pass' it is by generate entropy.
Chemistry explains inorganic things, those inorganic things become increasingly complex, eventually able to reproduce somehow, so you look to biology for explanation. You get evolutionary biology which might kind of explain how we came to be (super-self aware beings, capable of perceiving things, like time for example, or creating the internet to share ideas, or cars to commute). Then social/behavioral sciences attempt to explain us specifically. But even more fundamental than that first step (chemistry) is physics and math. And physics and math tell us that we are moving to a state of more entropy. Sometimes it feels like this is the best explanation for why we behave the way we do (driving to jobs we hate to do nothing important, making nuclear bombs, etc.).
End result is we're fked!
End result is we're fked!
I liked the example of water spilling onto the floor. I was trying to explain this point to my 7-year old the other day. As crazy as it sounds, the laws of physics don't say that the water couldn't jump off the floor and back into the bottle. The laws of physics are equations and equations are equally true if you reverse the left and right sides. In terms of the equations, that water in the bottle equals the water on the floor (along with the increase in heat energy and other effects), so there's no fundamental physical reason you can't go from one to the other. The reason why you don't ever see it is because it is astronomically less probable to happen in reverse.
I love these discussions, they make my brain hurt in a good way. However, I've trouble applying them to daily life. Is there something we should change in ourselves because of these new insights?
I don't think you really have to apply these things to your daily life. It is merely a question of _why_ is it that you feel time in your daily life like you do. It's as much of a question of philsophy as it is a question of physics.
I treat it as very base: be glad that we are who we are, that we can ponder these types of questions, and that it's OK that we may never get any hints, let alone answers, to these questions. Feynman has a good answer to something similar to this in one of those interviews from the 80s; he was perfectly okay with not understanding everything about the universe.
Even a skeptic philosopher, who would say most things can't be proven beyond the self, would probably agree that one of the things we have direct experience of is change.
"How can I tell that the past isn't a fiction designed to account for the discrepancy between my immediate physical sensations and my state of mind?" -- The Man In The Shack, The Hitch-Hiker's Guide To The Galaxy
True, but that's why I said "probably agree". You can be a solipsist and disagree with the existence of time, but that doesn't seem to be a very useful philosophy.
Considering that the first post isn't "Lunchtime is doubly so" consider your geek cards revoked.
It's interesting, because usually people/physicists that space is the emergent thing, and time is the fundamental dimension. I'm also glad that people are trying to reduce the number of dimensions rather than adding to them.
If you zoom out far enough everything is just your brain tripping balls trying to process electric signals from faulty/limited sensors.
What exactly is 'tripping balls' if it is not comprised of electrical signals? Saying consciousness is 'just' this thing or another is, in my mind, making trivial the most profound riddle in all of existence.
For an interesting book on the subject of time in the philosophy of physics, see Huw Price's Time's Arrow and Archimedes' Point. It does a fairly good job of laying out what the problems are.
* http://prce.hu/w/TAAP.html
* http://prce.hu/w/TAAP.html
I mentioned this in a previous discussion, some really interesting fringe research going in. Retrocausation
https://experiment.com/projects/are-we-catching-photons-trav...
https://experiment.com/projects/are-we-catching-photons-trav...
[deleted]
"All time is all time. It does not change. It does not lend itself to warnings or explanations. It simply is. Take it moment by moment, and you will find that we are all, as I've said before, bugs in amber." -Kurt Vonnegut, Slaughterhouse-Five
"Time doesn't flow, we flow."—Michael Crichton
(Not-a-Physics person)Question: If time isn’t linear, can we have perpetual motion machines?
Time is just a measurement that we haven’t quite nailed down the definition of yet.
We have a very precise definition of time: a second is "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom". It is used in a lot of physical equations which are very accurate at describing the universe as we observe it.
There are some philosophical questions regarding time. Questions about the arrow of time, entropy, causality, etc... For instance we may have trouble relating time and entropy, but it doesn't mean both of these concept are not well defined by themselves.
There are some philosophical questions regarding time. Questions about the arrow of time, entropy, causality, etc... For instance we may have trouble relating time and entropy, but it doesn't mean both of these concept are not well defined by themselves.
> We have a very precise definition of time
> a second is
Well that's a very precise definition of a second (unit of time), but not of time itself.
> a second is
Well that's a very precise definition of a second (unit of time), but not of time itself.
Yet, historically and practically the notion of 'time' has always been tied to a clock - the daily cycle, the change of seasons, etc. For example, when people said, "time has passed," they meant a certain number of natural cycles - days, seasons or years. The abstract, "theoretical" time, untied to any clock, is a relatively recent invention and, in fact, very well may be a fiction.
Of course relativity also complicates things with time as well. Whose second? Even if you have two different caesium-133 atoms monitored, one on earth and one on a satellite they won't rise at the same rate although both are defined the same.
I guess the real "illusion" would be that if there is truly nothing to be a frame of reference there is nothing for time to "flow" relative to.
I guess the real "illusion" would be that if there is truly nothing to be a frame of reference there is nothing for time to "flow" relative to.
How easy is it for physicists to mistake their models for reality? Equations are ways of representing reality. They are not reality. They are literally abstractions. Yes, it's another way of seeing and thinking about a thing, but it is not the thing... at all. Like a description of 4d space. Isn't a thing in reality, it is an abstraction. The only things that are not abstractions WRT time are movement and matter. Period. When ever you start freezeframing and creating integrations (4d view of time), then you've crossed into the world of the abstract and the non-existent.
As a coworker of mine would say: "A watched pothead never toils." I have always found it amusing when people talk about time's existence. It has always seemed like a ruler or a measuring stick; t = d/v, to me. Some people disagree as to it's existence but I think perhaps the problem isn't with our concept of time but with our definitions of existence.
a) Consciousness is just your brain trying to anticipate the future.
b) Your brain compresses (normalises?) repetition in memories. So even if day to day events happen at normal speed, the years seem to fly by when you reflect on them. If your life seems to be flying-by then maybe you need more novelty.