The idea that a quantum effect is necessary for consciousness to function is still in the realm of philosophy. Penrose proposes that it is necessary, but other theories of consciousness do not indicate that it is needed. For example, Daniel Dennett proposed a theory called multiple drafts model, which doesn't indicate that quantum effects are needed, in his 1991 book Consciousness Explained. A philosophical argument on either side isn't scientific proof, although philosophical analysis can indicate key differences in the types of models and show what type of experimental differences might be observed. But since there isn't a clear consensus among philosophers, there isn't conceptual support that a quantum mind theory is needed.