 Matter and form are the constitutive principles of a thing, but there are three principles of change: matter, form, and privation. According to Kilwardby, privation ‘is not pure nothing’ or even pure absence of form but the state of ‘actively’ lacking that something imperfect has with respect to fulfillment (E 3, 31)—and only in this way can privation be understood as a principle of change. Privation is the state of a potentiality that does not have the perfection that is owed to it (E 3, 30). In that sense, privation is associated with active  potency.[7]