Gary Marcus

astonished that anyone knowledgeable could claim that neural nets are (obviously) an “abstraction of neural processing” when we don’t yet know how brains work. if you don’t know how Y works you can’t really speak with certainty about whether X is an abstraction of Y. Period.https://twitter.com/tyrell_turing/status/1200072223299657728 …

Oy. “Knowing how Y works” means having a theory of Y that explains something and hasn’t been contradicted by evidence, yet. “X is an abstraction of Y” just means a theory of Y based on a simpler theory X. How can you ever “know how Y works” without making abstractions?

symbol-manipulation has not been rejected by evidence yet, but most readers of this thread are "sure" the brain doesn't do it (despite abundant evidence from linguistics and psychology that suggests symbol-manipulation is part of what brain do)

Not here to fight, but may I ask how symbol-manipulation is implemented in the brain (if not by a network of interconnected neurons)?

Don't know the answer to this, but (a) I made some suggestions in The Algebraic Mind, chapter 3, and (b) I also don't know how short-term memory (of the write-once, then immediately retrieve variety) is implemented in the brain, but that doesn't make me doubt its existence.