As I understand it, the tuition differential is only for public universities, not private ones. Private universities/colleges may cover the full financial need of international students if they cannot afford tuition.
Source: I was an international student and got nearly a full ride to a private SLAC.
PDDL files do outline objects, predicates, actions, etc. in a machine-readable way, but in a much more expressive manner than can be done with something like JSON.
PDDL is designed to be machine readable, but also human-readable and writable. I would say you would write PDDL when you want to provide a description of the rules of a domain to an algorithm that does automated planning and acting. This could be an autonomous agent of any sort, doesn't necessarily have to be embodied/robotic in nature.
The inverse of your example sentence would be something like - "I don't have a good immune system, so I would need medicine if I got a cold" - which makes sense, and is analogous to "Reality is not different, so we do need affirmative action."
This is a good collection of resources, but even more valuable would be the syllabi and homework sets from graduate-level theoretical physics courses, which can guide the interested learner through the vast amount of material, and help them gauge what is a reasonable pace of progress and not get bogged down (this has happened to me whenever I've tried to self-study from textbooks).
Source: Just got my PhD in theoretical high energy physics.
This may have been true during Darwin's time, but it simply does not apply in today'a academic world. The level of competition for grants, publications, etc. is way, way higher than before. Not that I've conducted a survey, but I'm pretty sure every professor at an R1 university works at least 60 hours a week, if not more.
Source: Am finishing up my PhD in theoretical high energy physics.
Source: I was an international student and got nearly a full ride to a private SLAC.