 With these preliminaries in place, Avicenna’s conceptual critique begins (Avicenna, [Ph], 2.8 [1–4]; also see McGinnis 2007a, 2007b; and Lammer 2018, §5.3). He first asks whether the void actually exists or is absolutely nothing. If one says that the void is absolutely nothing, Avicenna happily agrees; for if it is absolutely nothing, then it does not actually exist. Those who affirm that the void actually exists, then, cannot simply say that it is nothing, but must provide some positive features about it. Avicenna next notes that void space is frequently described as being of either a greater or lesser extent, for the void space between two cities on Earth, for example, is less than the void space between the Earth and the heavens. This property of being more or less is none other than that of quantity. Thus if a void should exist, it would possess some quantity either essentially or accidentally. If quantity belongs to void accidentally, and every accident must belong to a substance, then void is joined to a substance possessing quantity. The quantity in question is necessarily three-dimensional, but as noted when discussing continuity, three-dimensionality follows upon the form of corporeality. The form of corporeality, however, causes the existence of a body. Thus void would belong to a body as an accidental feature of it, a seeming contradiction. 