And the human got their definition of cup by seeing a lot of things others called a cup and extrapolating rules, something that's already obtainable for some problems with solutions like neural networks.
The problem is: nobody knows. Its a bit like two cavemen banging rocks together until one says "hey, lets use these rocks to kill something" and the other one goes "eh? How?" and the first one says "I don't know, keep bashing until something dies.."
(Diagnostic experiment: Is there a significant subset of "cups" that a naive neural network would always fail to include or only include when also including a significant subset of non-"cups"?)