15.20, Tuesday, 2nd November 2010
Speaker: Mike Beaton
Title: Integrated Information and Externalism
Abstract: Tononi’s Integrated Information Theory of consciousness comprises two major claims. The first claim is that integrated information for the subject (in some initial, pre-theoretic sense) is the right kind of thing to correspond to consciousness. This, I will briefly suggest, is correct. The second major claim is that Integrated Information (Φ), as Tononi goes on to operationalize it, is the right kind of thing to formalise these pre-theoretic intuitions. Here, I will argue, Tononi goes wrong. Tononi’s Φ is a thoroughly internal measure – in fact, a measure of how much information a brain carries about itself. Tononi holds certain (widely shared) internalist intuitions about consciousness, which may make this seem a plausible measure of consciousness. Here, I will attempt to propose one externalist alternative, involving an externalist, subjectivist account of information itself. I will informally review Cox’s theorem, which shows that the laws of probability are the only consistent way to model reasoning in the face of uncertainty. I will argue that this result shows that probabilities are best seen as characterising states of knowledge of rational subjects. More specifically, any given probability is a partial characterisation of how a rational subject should (be prepared to) act in an uncertain world. Equally, Shannon information is well-defined when probabilities are well-defined, so information itself is best seen as a (partial) characterisation of the (potential) behaviour of a rational subject. I will point out that information for a subject (in the sense just developed) must be integrated in a way which matches Tononi’s pre-theoretic intuitions. Therefore, I will argue, we already have a theory of integrated information (in the pretheoretic sense) in our pre-existing theories of probability and information (when these are given a subjectivist, ‘Bayesian’ reading). Since I have argued elsewhere that embodied, practical rationality and phenomenal consciousness are inseparable, I believe that this existing theory is already the right theory to capture phenomenal consciousness, whereas Tononi’s internal measures are not.