The subject matter is perhaps best characterized as the subjective quality of experience. When we perceive, think, and act, there is a whir of causation and information processing, but this processing does not usually go on in the dark. There is also an internal aspect; there is something it feels like to be a cognitive agent. This internal aspect is conscious experience. Conscious experiences range from vivid color sensations to experiences of the faintest background aromas; from hard-edged pains to the elusive experience of thoughts on the tip of one’s tongue; from mundane sounds and smells to the encompassing grandeur of musical experience; from the triviality of a nagging itch to the weight of a deep existential angst; from the specificity of the taste of peppermint to the generality of one’s experience of selfhood. All these have a distinct experienced quality. All are prominent parts of the inner life of the mind. We can say that a being is conscious if there is something it is like to be that being, to use a phrase made famous by Thomas Nagel.1