I thought I’d make a little note about this because quite a lot of people have been talking about this issue.
Ray Kurzweil addressed the Singularity Summit on Sunday and gave a brief summary of his opinions on some of the other preceding talks. He specifically answered criticism from others of our ability to ever model the brain using classical computing due to the presence of quantum effects in the brain. I don’t know of any supporters of this hypothesis other than Penrose and Stuart Hameroff, but maybe they are out there. He supported his viewpoint by saying that ‘The brain doesn’t factor large numbers’.
I agree with the statement that the brain is not necessarily ‘quantum computing’, but I disagree with this particular argument, because the brain does do lots of other things which quantum computers might ALSO be good at, such as pattern recognition, image processing and memory retrieval (database searching). So I think any argument as to why the brain isn’t quantum computing needs to be a bit more watertight (start by explaining decoherence for example) if you’re going to tackle this issue.
As a secondary effect, it perpetuates the myth that factoring is the only thing QCs will ever be used for. Which is sad, because a lot of smart people might have taken that impression away with them.