A Treatise of Human Nature - Volume 3

can never be founded on an inactive principle; and if reason is inactive in itself, it must remain so in all its shapes and appearances, whether it exerts itself in natural or moral subjects, and whether it considers the powers of external bodies or the actions of rational beings.

It would be tedious to repeat all the arguments by which I have proved^a that reason is perfectly inert and can never either prevent or produce any action or affection. It will be easy to recollect what has been said upon that subject. I shall only recall on this occasion one of these arguments, which I shall endeavor to render still more conclusive and more applicable to the present subject.

Reason is the discovery of truth or falsehood. Truth or falsehood consists in an agreement or disagreement either to the real relations of ideas, or to real existence and matter of fact. Whatever, therefore, is not susceptible of this agreement or disagreement is incapable of being true or false, and can never be an object of our reason. Now it is evident our passions, volitions, and actions are not susceptible of any such agreement or disagreement; being original facts and realities, complete in themselves, and implying

^a Book II. Part III. Sect. 3.