Quantum Coherence in Brain Activity: Why and Whether?
The arguments from mathematical logic (Gödel incompleteness, Turing machines) suggest that conscious understanding is something that lies outside computational activity. If the conscious brain is capable of such things, it is hard to see how its activities can be explained entirely in terms of classical physics. This suggests that there must be some kind of large-scale quantum coherence as part of brain activity. Although neuronal microtubules have been argued to be the most probable location for such activity, it has seemed unlikely that sufficient isolation from environmental decoherence could take place. However, recent experimental results have indicated a much more positive indication of such activity than had previously seemed possible.