25
The Cartesian Soul Hylomorphism is a theory based on the idea of the soul. The word “soul” might carry religious connotations or seem to evoke theological or pre-scientific ideas about psychology, but the hylomorphic soul is distinct from this idea of the soul as will be explained below and avoids the central problems that confront typical understandings of the soul. In spite of the possible connotations of the term “soul,” a theory of identity based on something beyond mere matter is appealing because it makes sense of various intuitions that link identity with subjectivity. It is easy to imagine someone’s thoughts and psychological qualities inhabiting a different body after a swap occurs in a Freaky Friday scenario. In such a case, it makes intuitive sense to suppose that this is because what is essential to each person is not the body but the soul, or in more modern terminology the mind, regardless of whether such a case could transpire in this possible world. Therefore, a theory of identity that can make sense with this point in mind might resolve the issue, at least more adequately than those that do not. The popular conception of the soul finds a strong articulation in the work of Descartes. According to Descartes, human persons are in essence res cogitans, that is, thinking things. Because it is possible to doubt the existence of the body but not the existence of the mind that does the thinking, Descartes believed that our essence was mental. In other words, human persons are fundamentally subjects of experience as opposed to extended bodies in space. Although a Cartesian might believe the self cannot in reality be separated from the body, it can conceptually be separated without forfeiting identity because it is said to be an independent substance. Thus, the Cartesian theory makes sense of intuitions that suggest psychological or subjective properties are sufficient to retain the numerical identity of human persons. There emerge two major problems that the Cartesian must address: why each soul seems causally connected in some way to a body and how consciousness can appear to split. The first challenge is known as the interaction problem and can be variously phrased, but the central issue is how an immaterial soul can have any causal connection with a material body without violating the law of conservation of energy. The body in general, and the brain in particular, interacts regularly with our mental life insofar as bodily events cause changes in attitude, feeling, cognition, and other subjective properties. The Cartesian might respond with the parallelist view that changes in the soul happen to accompany changes to the body, but that would entail an awfully lucky number of coincidences. Without appeal to further theological premises, a resolution seems far-fetched. It is more parsimonious to jettison the idea of the soul being an independent substance when explaining its
