ABSTRACT
Although it applies only to certain elements of consciousness, an interesting identity theory has been advanced by Paul Churchland. His views depend upon the theory of cognition that has come to be known as connectionism and which is currently extremely influential. Connectionist models begin with the idea of a network composed of very simple units whose individual outputs depend upon the set of inputs they receive from all the units feeding into them. In this, they are taken to be rather like the brain. It is possible to regard the whole network as defining an abstract space, within which each of its possible states forms a vector. Churchland’s identity theory is that there are subnetworks of the brain, operating in an essentially connectionist fashion, which correspond to – in fact can be identified with – states of sensory consciousness (colours, sounds, smells, etc.). Thus the abstract space associated with these sub-networks is also a space of qualitative consciousness, and the vectors within the space correspond to particular sorts of sensory experience. The problem with this view is that it confuses the sources of conscious experience with conscious experience itself. That is, while we might agree that activation of the appropriate neural ‘vectors’ is required for conscious experience, this would not show that such activation was identical to experience. In fact, there are reasons to suspect that these activations can occur in the complete absence of consciousness.
