Consciousness as Integrated Information: a Provisional Manifesto

The integrated information theory (IIT) starts from phenomenology and makes use of thought experi- ments to claim that consciousness is integrated information. Specifically: (i) the quantity of consciousness corresponds to the amount of integrated information generated by a complex of elements; (ii) the quality of experience is spec- ified by the set of informational relationships generated within that complex. Integrated information () is defined as the amount of information generated by a complex of elements, above and beyond the information generated by its parts. Qualia space (Q) is a space where each axis represents a possible state of the complex, each point is a probability distribution of its states, and arrows between points represent the informational relationships among its elements generated by causal mechanisms (connections). Together, the set of informational relationships within a complex constitute a shape in Q that completely and univo- cally specifies a particular experience. Several observations concerning the neural substrate of consciousness fall natu- rally into place within the IIT framework. Among them are the association of consciousness with certain neural systems rather than with others; the fact that neural processes un- derlying consciousness can influence or be influenced by neural processes that remain unconscious; the reduction of consciousness during dreamless sleep and generalized sei- zures; and the distinct role of different cortical architectures in affecting the quality of experience. Equating conscious- ness with integrated information carries several implications for our view of nature.