Being in Time

Any theory that purports to explain how phenomenal experience arises in the system in question (such as the brain) must do so in terms that are meaningful within the system itself. Simply put, because my experience of the world cannot be up to an outside observer, it cannot be explained by positing entities, such as whole-brain state variables, if those can only be known from the outside. This is the sense in which theories of experience must be intrinsic (Fekete, 2009; Fekete and Edelman, 2011). Theories of phenomenal experience that are computational (Fekete and Edelman, 2011) are subject to another obvious constraint. The computations to which experience is reduced in such theories must be tractable, given the physical limitations of the implementing system (the brain). For instance, if a transition between two experiential states is to be explained by a computation performed on a certain variable, the brain must be capable of completing that computation within an appropriate time frame. A popular theoretical construct that runs afoul of the above considerations is that of an instantaneous state of the brain (or of a part of the brain). A mind implemented in a brain is a distributed entity, because of the generally non-negligible delays in the propagation of signals within the brain.3 If it takes a finite time for neurons that form a network to communicate, in what sense is an instantaneous state of the entire network “there” for the network itself, rather than for an omniscient zero-lag outside observer? Casting theories in terms of instantaneous brain states is also problematic from the functional standpoint because such states, taken in isolation, fail to constrain the system’s dynamics, and therefore lack intrinsic causal powers.4 Only with time, as the system’s far-flung components interact, does its dynamics become apparent — most importantly, to itself, that is, intrinsically. Not surprisingly, the passage of time is also critical for phenomenal experience. Because all the components that can in principle contribute to the system’s dynamics participate in shaping its trajectories through the state space and in imposing structure on this space (ruling some classes of trajectories in and others out), phenomenal experience is holistic: it emerges from the dynamics of the entire brain (Fekete and Edelman, 2011). But as we just noted, because signaling within any network of neurons cannot be instantaneous, the holism of experience implies that it must be inherently temporally extended. It is tempting to assume that this conclusion implies merely that there must be a delay between exposure to a stimulus and its experience, as expressed by the view that “the phenomenal experience emerges when all relevant neurons in a network are informed about their own population state” (Malach, 2007). This view is, however, troublesome in light of the computational difficulties associated with the problem of attaining agreement in asynchronous distributed systems (Pease, Shostak, and Lamport, 1980; Lamport, Shostak, and Pease, 1982). In realistic distributed systems, of which the brain is but one example, failures such as faulty elements and unreliable communication links conspire to make agreement (e.g., about the value of a global variable) hard to achieve.