Chapter II: On the Principles of Human Acts

3. - Three principles of human acts are numbered: 1° cognition, 2° will, 3° liberty. For these are constitutive of them, and therefore are required for any properly human act, as is clear from the definition of a human act and from the very nature of the thing. For will necessarily supposes prior cognition; for nothing can be the object of the will unless it has first been apprehended by the help of the intellect. Hence the axiom: Nothing is willed unless first known. But liberty supposes each of these; for liberty is the faculty of choosing, or of determining oneself to some act; but choice cannot be made unless the will moves itself toward this or that part which has first been known.

Cognition here is the same as conscience, concerning which in the following treatise. Here, therefore, we shall speak only of will and of liberty, or of the voluntary and of the free, and also of the impediments of each.