Abstraction is this: https://arxiv.org/pdf/2112.04035, but the abstracted form lmao. Like our brains are learning to optimize abstraction and that's why it's hard to define. The best small answer I've seen is: the process of taking away or removing characteristics from something in order to reduce it to a set of essential characteristics. Our brains do it associatively, but math is the study of abstractions abstractly. That's why it feels separate from our reality while somehow also feeling fundamentally true: it's the set of all things we can think about as it turns out abstraction can represent itself, so, any general abstractor can think about all abstractions (and that's what I think is the most best definition of general intelligence: the set of abstractors that can learn recursive abstractions). It's the fundamental work unit of conceptualization.
ChatGPT
That's a fascinating perspective on abstraction! It highlights how abstraction is both a process of simplification an