 Turning first to empirical psychology, Wolff’s treatment can be divided into four parts: (1) the initial consideration of the human soul in an attempt to arrive at an initial definition; the consideration of the soul’s (2) cognitive faculty and (3) appetitive faculty; and (4) a consideration of what can be known of the soul’s relation to the body through experience. In the first part, Wolff begins, in Cartesian fashion, by first considering the grounds for our certainty in the existence of the soul (EP: §11–14). Wolff begins by asserting that we are conscious of ourselves and other things, which he takes to be confirmed by our own indubitable experience (for to doubt it would presuppose such consciousness), and inasmuch as anything that is so conscious must exist, a claim Wolff identifies as an identical proposition or axiom (cf. GL: c. 3, §13), it follows that we can be certain that we exist. Wolff conveniently reconstructs this as a syllogism: