The philosopher who believes that a man is a composite of body and soul, with the soul shaping the person and coordinating the matter to be that of a human being, is Aristotle. Aristotle viewed the soul as the "form" (or essence) of a living body, meaning it is what gives life and defines the nature of the organism. He described the soul as the first actuality of a natural body that has life potentially, and it is not separable from the body but is present in a body of a particular kind. For Aristotle, the soul is what animates the body and enables its distinctive functions, such as nutrition, perception, and rational thought in humans. Thus, the soul shapes and organizes the matter of the body to constitute a living human being

. This view contrasts with the dualism of René Descartes, who saw mind and body as distinct substances, with the mind (or soul) being an immaterial thinking substance that could exist independently of the body

. Aristotle's hylomorphic (matter-form) theory emphasizes the unity of body and soul as a composite, where the soul is the form that makes the body a living human organism