Armstrong rejects dispositionalism, the idea that dispositional properties (or powers as they are sometimes referred to) are ontologically significant and have an important role in explaining laws of nature. Armstrong believes that the challenge that dispositionalism presents for his account of laws of nature is not in the case of "manifested" dispositions (say, a glass dropping on the ground and breaking) but "unmanifested" dispositions (the fact that counter factually if one were to drop the glass on the ground, it "would" break). Armstrong simply states that the disposition is simply in the nature of the instantiated properties of the thing which is supposed to have the disposition.