[the_af]

Before CPUs existed, we would compare brains to steam engines. There was a very interesting article posted here on HN a while ago, explaining why humans always pattern match their understanding of the "mind" (or "soul") to whatever technology is fashionable in their time: steam engines, computers, etc. It also explained the pitfalls of doing so.

I think there is at this time no indication human brains are in any way similar to CPUs. It might be interesting to consider the question, of course.

[Stupulous]

But steam engines and hydraulics and gear mechanisms are all Turing complete. There is nothing wrong with those models. You could build a brain out of any of them, unless the brain computes something that is not computable.

If the brain does something that is not computable, that's a direct challenge to some of our most established science. It is possible, but I think very unlikely.

[the_af]

> You could build a brain out of any of them, unless the brain computes something that is not computable.

Could you? That's sort of begging the question. We do not know if something "Turing complete" can be used to build a brain like the human brain. That's precisely the point.

> If the brain does something that is not computable, that's a direct challenge to some of our most established science.

A challenge for computational neuroscience maybe. Otherwise I don't see the challenge for neither neuroscience nor computer science. If someone wants to make the claim you can build a human brain out of something Turin-machine-like, that's an extraordinary claim, not established science.

[Stupulous]

The argument I'm responding to is one that says people are wrong about brains being computers because people always believe they can make brains out of technology of the day. My point is that all of these things are the same theory, and it is one that has not been disproven.

If a brain cannot be produced in a turing machine, it must perform some non-computable activity. That would mean physics cannot be accurately simulated in a computer, which I believe would be earth-shaking in that world. That brains can be reproduced in a simulation is a default assumption, that something composed of molecules can produce outcomes that cannot be computed is an extraordinary claim, for which, I believe, there is no evidence.

[sudosysgen]

To be fair, CPUs are Turing machines. That makes them much more comparable to anything that mainly does information processing than to anything else.

[the_af]

I think the danger is that it's always "obvious" that the current fashionable tech works in analogous ways to the mind/brain. We can spend all day finding ways in which they are similar; for example how the brain does information processing and the CPU does too.

The point is, I think, people from the steam engine era had similar reasons why the mind/soul was exactly like a steam engine. I won't try to reproduce them here, but I'm sure there were convincing arguments at the time. Who has the awareness to claim, before the current fashionable technology becomes unfashionable, that maybe no, the brain is not a close match for an information processing machine? ;)

[TomMarius]

I thought it was about similarity of simulated neurons, not the CPU itself.