Integrated Information Theory, Intrinsicality, and Overlapping Conscious Systems

Integrated information theory (IIT) identifies consciousness with having a maximum amount of integrated information. But a thing's having the maximum amount of anything cannot be intrinsic to it, for that depends on how that thing compares to certain other things. IIT's consciousness, then, is not intrinsic. A mereological argument elaborates this consequence: IIT implies that one physical system can be conscious while a physical duplicate of it is not conscious. Thus, by a common and reasonable conception of intrinsicality, IIT's consciousness is not intrinsic. It is then argued that to avoid the implication that consciousness is not intrinsic, IIT must abandon its exclusion postulate, which prohibits overlapping conscious systems. Indeed, theories of consciousness that attribute consciousness to physical systems should embrace the view that some conscious systems overlap. A discussion of the admittedly counterintuitive nature of this solution, along with some medical and neuroscientific realities that would seem to support it, is included.