Abstract

Aquinas claims against Avicenna’s causal determinism that even a sufficient cause can be impeded. I analyze Aquinas’s claim in the context of his reading of Aristotle’s Metaphysics (VI 3) and argue that it ultimately rests on the idea that no cause has the per se effect of disposing matter to form. A cause can thus be impeded by the indisposition of matter while being sufficient for the production of form. By contrast, Avicenna understands that the per se effect of natural causes is precisely to dispose matter, thus accounting for the removal of impediments, and this is why, I argue, there is no sense in which a sufficient cause can be impeded on Avicenna’s view.