 Thus, despite what the language of “efficiency” might suggest, James’ account of how the intellect moves the will is similar to his account of how the sense organ moves the power of sense and how the imagination moves the intellect: in all three cases the motion is of the “excitatory” variety; the power itself as the formal cause of its acts supplies the lion’s share of the voluntary act’s causality. If anything, the will itself can be considered to be an efficient cause (in the first sense of the word), if only per accidens. This is because the will, like heavy objects but unlike the intellect and the senses, belongs to the class of things that both move themselves formally and move others efficiently. Thus, just as a heavy object is formally self-moved as a result of its heaviness but moves another efficiently inasmuch as it divides the medium it traverses, so too the will is a self-mover that efficiently moves the intellect and the other faculties, and hence can be said to move itself  per accidens (Quodl. I, q. 7, p. 98, 633–640). 