While the claim that certain functional states are sufficient for conscious experience has received substantial critical attention, the claim that functional states are necessary is rarely addressed. Yet the latter claim is perhaps now more common than the former. I aim to revive and revise a neglected argument against the necessity claim, by Michael Antony. The argument involves manipulating a conscious subject's brain so as to cancel a disposition which is supposedly crucial to the realization of an experience that the (...) subject is having at the time. The key step in the argument is to show that, contrary to what the functional necessity claim implies, the experience can survive such a manipulation. I defend that key step in a new way, by arguing that since the manipulation cannot influence the subject's thoughts, emotions, or behavior, there is no reason to suppose that it alters his conscious experience. (shrink)

The human mind is constituted by inner, subjective, private, first-person conscious experiences that cannot be measured with physical devices or observed from an external, objective, public, third-person perspective. The qualitative, phenomenal nature of conscious experiences also cannot be communicated to others in the form of a message composed of classical bits of information. Because in a classical world everything physical is observable and communicable, it is a daunting task to explain how an empirically unobservable, incommunicable consciousness could have any physical (...) substrates such as neurons composed of biochemical molecules, water, and electrolytes. The challenges encountered by classical physics are exemplified by a number of thought experiments including the inverted qualia argument, the private language argument, the beetle in the box argument and the knowledge argument. These thought experiments, however, do not imply that our consciousness is nonphysical and our introspective conscious testimonies are untrustworthy. The principles of classical physics have been superseded by modern quantum physics, which contains two fundamentally different kinds of physical objects: unobservable quantum state vectors, which define what physically exists, and quantum operators (observables), which define what can physically be observed. Identifying consciousness with the unobservable quantum information contained by quantum physical brain states allows for application of quantum information theorems to resolve possible paradoxes created by the inner privacy of conscious experiences, and explains how the observable brain is constructed by accessible bits of classical information that are bound by Holevo's theorem and extracted from the physically existing quantum brain upon measurement with physical devices. (shrink)