What in the world is consciousness?

The concept of consciousness is multifaceted, and steeped in cultural and intellectual history. This paper explores its complexities by way of a series of contrasts: (i) states of consciousness, such as wakefulness and sleep, are contrasted with awareness, a term that picks out the contents of consciousness, which range across all our psychological capacities; (ii) consciousness is contrasted to self-consciousness, which is itself a complex term embracing self-detection, self-monitoring, self-recognition theory of mind and self-knowledge; (iii) "narrow" and "broad" senses of consciousness are contrasted, the former requiring mature human awareness capable of guiding action and self-report, the latter involving the much broader capacity to acquire and exploit knowledge; (iv) an "inner" conception of consciousness, by which awareness is essentially private and beyond the reach of scientific scrutiny, is contrasted with an "outer" conception which allows that consciousness is intrinsically linked with capacities for intelligent behavior; and finally (v) "easy" and "hard" questions of consciousness are distinguished, the former involving the underlying neurobiology of wakefulness and awareness, and the latter the allegedly more mysterious process by which biological processes generate experience-the question of whether this final distinction is valid is a focus of current debate. Varied interests converge on the study of consciousness, from the sciences and the humanities, creating scope for interdisciplinary misunderstandings, but also for a fruitful dialog.