Gary Marcus

If we don't know the answer to (2), how can we be sure about the answer to (1)?

We know enough of the basics of how individual neurons turn inputs to outputs to create an abstraction of that process. That is the solid statement that supports (1). (2) is dependent on how neurons interact & what further complexities are needed to capture all the brain does.

It may be fruitful & fashionable to say we dont understand anything about the brain & so cant model it. But that's simply not how modeling works. Its iterative and you go with your best guess until contradictory evidence provides you with a better one.

But the problem Grace is that the advocates of ANNs do not take your position: They do not want to iterate to a better (biologically) model, but instead double down on this particular abstraction at this particular point in time.

With all due respect, I don't know who these practitioners you speak of are. Grace's position is the mainstream, in my opinion.

100% this! I know of nobody in the community who would say "today's ANNs are perfect models of the brain, let's not dig deeper".

I'm pretty sure there are quite a few in circles you don't inhabit.

What circles contain such folks?