  In Quodlibet X of the Advent Session, 1286, Henry returns to the problem of the self-motion of the will, introducing the notion of virtus ad movendum, through which the spiritual faculties (such as human voluntas) can produce and specify their own acts without an external mover. More especially, through this virtus ad movendum, which corresponds to the substantial form of the subject, the will is able to pass from the potency of desiring to the act of desiring, since it already “virtually” contains this act within itself. Henry thus surprisingly concludes that even the above-mentioned propositio magistralis (“si ratio recta, et voluntas recta”) does not undermine the superiority of the will. The proposition should be interpreted in the sense of simultaneity, and not causality, since the second faculty (ratio) does not necessarily determine the first (voluntas), but is only the conditio sine qua non of its operation. Finally, Henry concedes that the will cannot desire what it does not know, but denies that the will is determined in its choices by the intellect; in other words, that it cannot desire the opposite of what the intellect dictates.