 Simon’s general psychology is standard Aristotelian doctrine, in many aspects derived from Albert the Great’s and Aquinas’s psychological teachings. However, as we shall see, Simon sometimes conflates their views, suggesting he was not entirely aware of their opposition. Thus, Simon holds that the rational soul is the substantial form of the human body because it is that on account of which humans can perform their proper operation, i.e., intellection. However, unlike the substantial form of purely material things, the substantial form of a human being does not emerge from a natural arrangement of matter, but is given to the human body as its perfection by an external source, i.e., by the first cause. Simon then describes the soul both as the perfection (like Albert) and as the substantial form (like Aquinas) of the human body, but seems unaware of the conflict between Albert’s and Aquinas’s positions. For Albert, who wants to avoid psychological materialism, the soul is the perfection, and not the form, of the human body; a soul that is given to it by God. For Aquinas, however, who wants to make the rational soul the defining element in a human being, the soul must be the intrinsic substantial form of the human body, which is nonetheless separable after the body’s death. It remains unclear whether Simon intentionally conflated the two views, and if so, whether he thought the two views could be somehow reconciled.