To appear in The Encyclopedia of Cognitive Science Consciousness, Philosophical Issues about

There are a number of different matters that come under the heading of ‘consciousness’. One of them is phenomenality, the feeling of say a sensation of red or a pain, that is what it is like to have such a sensation or other experience. Another is reflection on phenomenality. Imagine two infants, both of which have pain, but only one of which has a thought about that pain. Both would have phenomenal states, but only the latter would have a state of reflexive consciousness. This entry will start with phenomenality, moving later to reflexivity and then to one other kind of consciousness. The Hard Problem of consciousness is how to explain a state of consciousness in terms of its neurological basis. If neural state N is the neural basis of the sensation of red, why is N the basis of that experience rather than some other experience or none at all? Chalmers (1996) distinguishes between the Hard Problem and “easy ” problems that concern the function of consciousness. The Hard Problem (though not under that name) was identified by Nagel (1974) and further analyzed in Levine (1983). There are two reasons for thinking that the Hard Problem has no solution. 1. Actual Failure. In fact, no one has been able to think of even a highly speculativ