[Certhas]

unoptimized? Hardly. Evolution has optimized our nerve systems for the task of heuristic information processing over tens or hundreds of million of iterations in parallel over billions of different implementations.

That part of your sentence is wrong, the rest (minds are nothing more than computers running on substrate) is wrong or meaningless, too. It just so happens that computation of the Turing model is one of the things human minds do, and badly. It's very much not the only thing. (Unless you mean computer in a sufficiently vague and abstract way as for the statement to be vacuous.)

[aswanson]

unoptimized? Hardly. Evolution has optimized our nerve systems for the task of heuristic information processing over tens or hundreds of million of iterations in parallel over billions of different implementations.

The biological method of information processing, calcium ion transfer, is demonstrably orders of magnitude slower than artificially devised methods by semiconductors. So this is physically not optimal and easily proved. So that part of my sentence is correct.

The rest of your comment is too ill-defined to refute, unless you hold that there is some non-material, extra-physical quantity of mental process that cannot be duplicated by engineering.

[jacquesm]

Having slower individual components running at ridiculously low power is a valid optimization because it allows very close packing of those components and levels of interconnection that we can only dream of in our designed systems.

The optimization is a subtle one but extremely powerful, and it will be a while before we can pack equivalent computational power in something of similar size and power requirements.

Think about the amount of hardware required to simulate a cat brain at reduced speed, then think about the amount of hardware in a cat brain.