Comment by kmoser
3 hours ago
A Turing machine operates serially on a fixed set of instructions. A human brain operates in parallel on inputs that are constantly changing. The underlying mechanism is completely different. The human brain is far, far more than a mere computation device.
Efforts to reproduce a human brain in a computer are currently at the level of a cargo cult: we're simulating the mechanical operations, without a deep understanding of the underlying processes which are just as important. I'm not saying we won't get better at it, but so far we're nowhere near producing a brain in a computer.
Any Turing complete computational device is computationally equivalent to any other, irrespective of whether it carries out the computation serially or in parallel or on a fixed set of instructions or an infinite set.
Unless you can demonstrate that the human brain can compute a function - any function - that exceeds the Turing computable, there is no evidence to even suggest it is possible for a brain not to be computationally equivalent to a computer.
I'm not saying it's impossible. I'm saying it's highly improbable to ever come close to fruition, since if you want to be completely accurate in your computations, you'd have to model the physical effects of every single atom in the brain and how they affect each other, in realtime (physically, chemically, electrically, etc.). Not only would that be computationally expensive, but you'd also need to know the complete set of rules for doing so, which includes how things interact at the quantum level.