"Is a single grain a heap" doesn't look like a paradox to me. A "heap" is just a word with an ambiguous definition. Once you define it, you'll have your answer :)
>Then, nothing's really the same
If that was the case, intelligence would've been impossible. We need similarities as well as the differences to be able to compare things (including abstract concepts)
>practically means that there is no underlying “red” or “apple” idea behind those concepts. That is something very valuable, Plato’s interpretation being debunked, that is.
This is one of my favorite parts in a fictional book Anathem. The question of syntax and semantics is explored there, and even a solution is suggested.
One may argue you are a different person even once some of your cells are replaced.
I imagine your next question might be whether you owe something to now-me if you were to take a loan from a previous-me.
This looks like a pair of mirror bugs. Yeah, the person is already a new one, but if we'd really treat them that way, we'd have to make our laws and morals even more complex. Instead, we just pretend that's the same person.