I often have read "I wonder if it _really_ understands or is just regurgitating ${something}" about AIs like this and I wonder what the difference really is? Ability to explain why it's one way and not the other? Extremely low frequency of errors? If it doesn't really understand lisp, maybe we'd expect to see a fairly high rate of incorrect interpretations?<p>Presumably most _actual_ compilers don't produce the correct solution 100% of the time (i.e. they have bugs), but I think it's reasonable to say that the compiler _understands_ ${programming language}. Maybe the difference between "understanding" and "just memorizing answers" is more subtle than often portrayed?