> But the brain is a general-purpose computer, not a speed-card computer, or English text computer, or binary digit computer, or Rubik's cube computer.
Look, I like the sentence. I like it so much I might steal it. But, that said I think analogising what the brain does to "general purpose computer" is a bit awry because we can invent algorithms, and given a process we can implement algorithms but I still tend to think there is something ineffable about thought/cognition which is NOT general purpose computation. It's a heuristic. I dunno what I think.
The computer analogy is definitely off. For one thing, rationality is kind of bolted on to our linguistic ability. It's not deeply seated in our brain; it takes substantial energy to engage in logical reasoning and we're not that great at it; even very skilled mathematicians make trivial mistakes.
Deeper in our brain is reasoning about causality. But even that is more of an input to our reactions and emotions than it is as a consciously accessible function, and it too is often wrong.
As you said, it's a heuristic. We certainly can't solve the halting problem with brain magic.
Implementing algorithms doesn't need a computer, and it doesn't need something that's not a computer.
That said, with enough willpower why couldn't you implement a universal Turing machine in your brain? I think you would need external memory (a tape) but that's not a problem.
Look, I like the sentence. I like it so much I might steal it. But, that said I think analogising what the brain does to "general purpose computer" is a bit awry because we can invent algorithms, and given a process we can implement algorithms but I still tend to think there is something ineffable about thought/cognition which is NOT general purpose computation. It's a heuristic. I dunno what I think.