You can’t build experience out of mere information. Not, at any rate, the way the Integrated Information Theory (IIT) seeks to do it. So says Garrett Mindt in a forthcoming paper for the JCS.

‘Information’ is notoriously a slippery term, and much depends on how you’re using it. Commonly people distinguish the everyday meaning, which makes information a matter of meaning or semantics, and the sense defined by Shannon, which is statistical and excludes meaning, but is rigorous and tractable.

It is a fairly common sceptical claim that you cannot get consciousness, or anything like intentionality or meaning, out of Shannon-style information. Mindt describes in his paper a couple of views that attack IIT on similar grounds. One is by Cerullo, who says:

‘Only by including syntactic, and most importantly semantic, concepts can a theory of information hope to model the causal properties of the brain…’

The other is by Searle, who argues that information, correctly understood, is observer dependent. The fact that this post, for example, contains information depends on conscious entities interpreting it as such, or it would be mere digital noise. Since information, defined this way, requires consciousness, any attempt to derive consciousness from it must be circular.

Although Mindt is ultimately rather sympathetic to both these cases, he says they fail because they assume that IIT is working with a Shannonian conception of information: but that’s not right. In fact IIT invokes a distinct causal conception of information as being ‘a difference that makes a difference’. A system conveys information, in this sense, if it can induce a change in the state of another system. Mindt likens this to the concept of information introduced by Bateson.

Mindt makes the interesting point that Searle and others tend to carve the problem up by separating syntax from semantics; but it’s not clear that semantics is required for hard-problem style conscious experience (in fact I think the question of what, if any, connection there is between the two is puzzling and potentially quite interesting). Better to use the distinction favoured by Tononi in the context of IIT, between extrinsic information – which covers both syntax and semantics – and intrinsic, which covers structure, dynamics, and phenomenal aspects.

Still, Mindt finds IIT vulnerable to a slightly different attack. Even with the clarifications he has made, the theory remains one of structure and dynamics, and physicalist structure and dynamics just don’t look like the sort of thing that could ever account for the phenomenal qualities of experience. There is no theoretical bridge arising from IIT that could take us across the explanatory gap.

I think the case is well made, although unfortunately it may be a case for despair. If this objection stands for IIT then it most likely stands for all physicalist theories. This is a little depressing because on one point of view, non-physicalist theories look unattractive. From that perspective, coming up with a physical explanation of phenomenal experience is exactly the point of the whole enquiry; if no such explanation is possible, no decent answer can ever be given.

It might still be the case that IIT is the best theory of its kind, and that it is capable of explaining many aspects of consciousness. We might even hope to squeeze the essential Hard Problem to one side. What if IIT could never explain why the integration of information gives rise to experience, but could explain everything, or most things, about the character of experience? Might we not then come to regard the Hard Problem as one of those knotty tangles that philosophers can mull over indefinitely, while the rest of us put together a perfectly good practical understanding of how mind and brain work?

I don’t know what Mindt would think about that, but he rounds out his case by addressing one claimed prediction of IIT; namely that if a large information complex is split, the attendant consciousness will also divide. This looks like what we might see in split-brain cases, although so far as I can see, nobody knows whether split-brain patients have two separate sets of phenomenal experiences, and I’m not sure there’s any way of testing the matter. Mindt points out that the prediction is really a matter of  ‘Easy Problem’ issues and doesn’t help otherwise: it’s also not an especially impressive prediction, as many other possible theories would predict the same thing.

Mindt’s prescription is that we should go back and have another try at that definition of information; without attempting to do that he smiles on dual aspect theories. I’m afraid I am left scowling at all of them; as always in this field the arguments against any idea seem so much better than the ones for.