On the Irreducibility of Consciousness and Its Relevance to Free Will

Integrated information theory of consciousness (IIT) starts from phenomenological axioms and argues that an experience is an integrated information structure. IIT holds that a system of connected elements—for example a network of neurons, some firing and some not—intrinsically and necessarily generates information, because its mechanisms and present state constrain possible past and future states. This intrinsic, causal kind of information—called cause-effect information (CEI)—measures “differences that make a difference” from the intrinsic perspective of the system. Moreover, a subset of elements only generates information to the extent that the cause and effect repertoires they specify cannot be reduced to the product of the repertoires specified by independent components (integrated information, ϕ). Finally, only maxima of integrated information (max ϕ) matter. A maximally irreducible cause-effect repertoire constitutes a concept. A complex is a set of elements specifying a maximally irreducible constellation of concepts (maxΦ), giving rise to a maximally integrated conceptual information structure or quale. Under certain conditions, such as the presence of noise and irreversibility, a maximum of integrated information may be associated with a “macro” spatiotemporal grain (say neurons over hundreds of milliseconds), rather than with a “micro” grain (say subatomic particles over microseconds). IIT accounts, in a parsimonious manner, for many, seemingly disparate empirical observations about consciousness, and makes theoretical predictions concerning the necessary and sufficient conditions for the presence and quality of consciousness in newborns, brain damaged patients, animals, and machines. Moreover, IIT has direct relevance for issues related to free will. According to IIT, when a choice is made consciously, in addition to satisfying the requirements of autonomy, understanding, self-control, and alternative possibilities, the choice is maximally irreducible. This is because the choice cannot be attributed to anything less than the entire complex that brings it about, nor is anything more than the complex required, as the complex provides the maximally irreducible set of cause-effects. If maximal integrated information is generated by a complex at a macroscale in space or time (groups of neurons, hundreds of milliseconds), the requirement for indeterminism is also satisfied: a conscious choice, while maximally and irreducibly causal, is also necessarily under-determined and thus unpredictable. In this view, indeterminism is not to be thought of as a sprinkle of randomness that instills some arbitrariness into a preordained cascade of mechanisms, decreasing their causal powers. Rather, indeterminism provides a backdrop of ultimate unpredictability against which information integration acts to impose autonomy, understanding, self-control, and alternative possibilities. Thus, according to IIT, a choice is the freer, the more it is determined intrinsically, meaning that it can only be accounted for by considering a large set of concepts, beliefs, memories, and wishes, all acting within a maximally irreducible complex. Which is to say that a choice is the freer, the more it is conscious.