ABSTRACT
If—as many biologists would have it—consciousness is just a physical property of a few special physical systems, this chapter implies that quantum mechanics does not apply to all physical properties. Wigner has forcefully stressed the point by means of a variant of the cat paradox, in which an exchange of information is introduced. He stresses the fact that, since the linearity of the laws of evolution is at the origin of the difficulties, it is linearity that should be given up. However, in view of the absence of any material evidence in favor of the existence of phenomena of this kind, Wigner expresses a preference for a theory that could be called one of "minimal violation." Wigner is even more respectful of the universality of great principles, for in his description, a reaction of consciousness on the rest of the universe—that is, on what people agreed to call "physical reality"—indeed exists.
