I argue that the science of the soul only covers sublunary living things. Aristotle cannot properly ascribe ψυχή to unmoved movers since they do not have any capacities that are distinct from their activities or any matter to be structured. Heavenly bodies do not have souls in the way that mortal living things do, because their matter is not subject to alteration or generation. These beings do not fit into the hierarchy of soul powers that Aristotle relies on to provide unity to ψυχή. Their living consists in their activities, not in having a capacity for activity.
Why De Anima Needs III.12-13.Robert Howton - 2020 - In Gweltaz Guyomarc'H., Claire Louguet & Charlotte Murgier (eds.), Aristote et l'âme humaine. Lectures de 'De anima' III offertes à Michel Crubellier. Leuven: pp. 329-350.