Thomist Anthropology and the Problem of Causal Interface

Abstract Aquinas’ anthropology is commonly believed to prevent the mind–body problem by treating the human being as one substance, and the soul as a formal cause. Thomists’ descriptions of Aquinas’ anthropology tend to understate or even omit its more dualistic elements, e.g., that the soul is an agent cause that moves the body, and that acts through the mediation of the ‘corporeal spirits’. More importantly, these descriptions overlook that Aquinas himself recognizes a problem of mental causality and even argues for some solutions to it. This paper aims to show that there is such a problem within Aquinas’ conceptual frame, and that contemporary Thomist anthropologies are also vulnerable to it.