Nothing but consciousness can unite remote existences into the same person
 John Locke, An Essay Concerning Human Understanding (1689). copy citation

Context

“But in the Great Day, wherein the secrets of all hearts shall be laid open, it may be reasonable to think, no one shall be made to answer for what he knows nothing of; but shall receive his doom, his conscience accusing or excusing him. 25. Consciousness alone unites remote existences into one Person. Nothing but consciousness can unite remote existences into the same person: the identity of substance will not do it; for whatever substance there is, however framed, without consciousness there is no person: and a carcass may be a person, as well as any sort of substance be so, without consciousness.” source