 When two, or more men, know of one and the same fact, they are said to be CONSCIOUS of it one to another; which is as much as to know it together. And because such are fittest witnesses of the facts of one another, or of a third; it was, and ever will be reputed a very evil act, for any man to speak against his conscience; or to corrupt or force another to do so…. Afterwards, men made use of the same word metaphorically, for the knowledge of their own secret facts, and secret thoughts; and therefore it is rhetorically said, that the conscience is a thousand witnesses. (Leviathan 7.4)