In Ned Block’s recent paper, published in Trends In Cognitive Science, he has defended his argument that perceptual consciousness overflows cognitive access from several recent objections (including from me). It is important that Block is defending overflow from cognitive access since he admits that perceptual consciousness does not overflow all access. Phenomenal consciousness consists in there being something that it is like for the subject of the experience and this suggests that there must be some kind of access to the experience. Block has elsewhere argued that some non-cognitive form of access can account for this but no account of non-cognitive access to date can explain what needs to be explained. Given this the anti-overflow position should remain the default until/unless we have much stronger evidence than what Block presents. Block suggests that there is a philosophical fallacy in the assumption that non-overflow is the default and in the insistence that we need strong evidence to overthrow the non-overflow position but this is not fallacious. It is the reasonable thing to do when you have very weak evidence that is consistent with two competing theories and one of those theories appeals to a mysterious place-holder concept while the other doesn’t.
Block suggests two possible forms of non-cognitive access. The first is a deflationary account and the second is a version of a self-representational theory. On the deflationary account we are aware of our mental states just in the having of them, in much the same way that we smile our own smiles just by smiling. Recall that what we are trying to explain is how a particular experience comes to be for the person who has it. When I feel a pain, not only do I experience the painful quality but I also experience it as mine. How can the deflationary account handle this? The deflationary account applies equally well to any state that happens to be instantiated in the brain. We can say that we are aware, in this way, of a state in the LGN, for instance, but surely we don’t want to say that it is phenomenally conscious.
The same problems arise for a self-representational account. One kind of self-representational account, holds that the higher-order awareness is itself a part of the state that it represents. But this is a variant of a cognitive access theory. Block seems to want a notion of self-representation that amounts to the state in question merely being instantiated (in the way a color sample represents the color just by being that particular color). But then every state would be conscious since every state represents itself merely by being instantiated. In fact every representation self-represents itself in this way but we don’t want to say that sentences are phenomenally conscious!
These notions of non-cognitive access are too weak to distinguish conscious mental states from unconscious mental states, or from any kind of brain activity at all. On the other hand a higher-order cognitive representation explains how a mental state can be for me; I am representing myself as being in that state, in some suitable way, so I will naturally experience the state as mine.
Block endorses only the reasonableness of tentatively accepting the overflow conclusion. But until we have a notion of non-cognitive access that can explain how a mental state can be experienced as mine that is at least as satisfactory as that given by cognitive access we need much stronger evidence than what Block presents to accept overflow.