I've heard it claimed before that brains could be quantum computers (I think it was on Through the Wormhole). Is there any evidence of this? I'm thinking about reading up on quantum computation, but don't know anything about quantum mechanics yet. I'm mostly interested in machine learning, and not yet sure if quantum computing is a worthwhile thing to study. I.e. I'm not sure if quantum computers are possible/practical. If brains are quantum computers, then I would at least know quantum computing is possible and practical in some sense.