Consciousness and explanation

Many aspects of our mental lives are conscious—an ache in tired muscles; the sight, smell, and taste of a glass of wine; feelings of happiness, love, anxiety or fear; trying to work out how best to test a hypothesis or structure an argument. It seems beyond dispute that at least some sensations, perceptions, emotional episodes, and bouts of thinking are conscious. But equally, there is much in our mental lives that is not conscious. It is a central idea in cognitive science that there can be unconscious information processing. It is also plausible that there can be unconscious thought and unconscious emotions; there are cases of ‘perception without awareness’; and perhaps even bodily sensations can sometimes be unconscious.1 What, then, is the difference between conscious and unconscious mental states? Is there, for example, something distinctive about the neural underpinnings of conscious mental states? An answer to this ‘what?’ question could be called (in some sense) an explanation of consciousness. We might, however, expect rather more from an explanation of consciousness than just a principle or criterion that sorts conscious mental states from unconscious ones. Suppose that we were told about a neural condition, NC, that was met by conscious mental states but not by unconscious ones. Suppose that this was not just an accidental correlation. Suppose that the difference between meeting this neural condition and not meeting it really was the difference that