Aristotelian Powers, Mechanism, and Final Causes in the Late Middle Ages
Henrik Lagerlund explores the topic of final causality in the High and later Middle Ages. He argues that the seventeenth-century mechanists weren’t the only ones critiquing and rejecting final causality. There were earlier figures who developed a form of mechanical materialism that eschewed final causes, most notably William of Ockham and John Buridan. Lagerlund begins with the way that Ockham and Buridan in the fourteenth century understood the mereology of the body. Bodily substances were composed of essential parts and integral parts. Essential parts were its metaphysical constituents, its matter and substantial form. Integral parts were its various extended bits. This distinction generated a metaphysical divide between material objects with extended substantial forms and simple, immaterial substances like God, angels, and the human soul. And this divide raises a number of philosophical puzzles for the entities on either side of it. Of special concern to Lagerlund is the numeric identity and unity of material substances across time. Lagerlund shows how Buridan in particular struggled to make sense of the identity and unity of material substances through time. In the end, Buridan could only say that material substances are successively identical through time; they are not totally or partially identical.