Matter and body are conceptually distinct ways of addressing the same physical reality, i.e. that which is fundamental in physical reality. Hence, material causes and bodily causes are on the same explanatory level, or so it seems to us. Yet medieval explanations of physical causation took a different route entirely, and adhered to a dual explanatory model in which matter and body play complementary roles. The 13th-century Dominicans, Albert the Great and Thomas Aquinas, for instance, distinguished matter from body, and supplied them with different functional roles in physical causation. For them bodies are the things in ordinary experience which cause via contrary causal features (e.g. heat and cold). In contrast, "matter" is a more complex concept, usually referring to something like a susceptibility or openness to the causal features of body. Matter and body are both required in medieval paradigms of physical causation. In my paper, I will shed light on the basic meanings of the two complementary concepts in some select 13th-century thinkers, and on the role of matter in particular in explaining causal action among bodies.
