Full Idea
Consciousness is the perception of what passes in a man's own mind.
Gist of Idea
Consciousness is the perception of what passes in a man's own mind
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 2.01.19)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.115
A Reaction
This sounds to me like one capacity of human consciousness, which is second-order awareness. I take animals to have first-order awareness (of the world), but not perception of their own awareness. Self-awareness is crucial to his concept of a 'person'.