"Consciousness is the faculty of awareness — the faculty of perceiving that which exists.

Awareness is not a passive state, but an active process. On the lower levels of awareness, a complex neurological process is required to enable man to experience a sensation and to integrate sensations into percepts; that process is automatic and non-volitional: man is aware of its results, but not of the process itself. On the higher, conceptual level, the process is psychological, conscious and volitional. In either case, awareness is achieved and maintained by continuous action.

Directly or indirectly, every phenomenon of consciousness is derived from one’s awareness of the external world. Some object, i.e., some content, is involved in every state of awareness. Extrospection is a process of cognition directed outward — a process of apprehending some existent(s) of the external world. Introspection is a process of cognition directed inward — a process of apprehending one’s own psychological actions in regard to some existent(s) of the external world, such actions as thinking, feeling, reminiscing, etc. It is only in relation to the external world that the various actions of a consciousness can be experienced, grasped, defined or communicated. Awareness is awareness of something. A content-less state of consciousness is a contradiction in terms."

Ayn Rand, Introduction to Objectivist Epistemology, 37