Abstract
Aristotle’s theory of causes requires a first, unmoved mover outside the sublunary world, along with soul as first and unmoved mover in the natural world below. Aristotle separates the charmed group of causes headed by soul that are jointly sufficient for typical animal behaviour from external causes. The border between external and charmed is permeable: crops growing in the field are co-opted to become an instrument of soul that nourishes the animal. (Instruments of soul like the sumphuton pneuma are internal to the animal from the start.) But no causes, not even the Unmoved Mover, may supersede soul as unmoved mover.