 Avicenna’s arguments against an actual infinity in nature are in general all directed against the possibility of infinite spatial magnitude. Consequently, since space must be finite (i.e., limited), all bodies must be limited, and in being limited they have shape. This conclusion holds for the cosmos as a whole as well. As for the shape of the cosmos, while such a topic takes us slightly afield from a discussion of infinity, it does round out Avicenna’s abstract discussion of body. For a number of reasons, Avicenna thinks that the shape of the cosmos must be spherical. While in some ways Avicenna takes this claim to be a matter of empirical observation, he also argues that since the nature of the heavenly bodies is completely homogeneous and unvarying, there cannot be dissimilarities in a heavenly body such that a part of it would be angular and another part rectilinear or such that part of it has one sort of curve and another part a different sort (Avicenna, [DC], 3; also Avicenna, [Ph], 1.8 [2] provides the general argument, albeit there it is applied to showing the sphericity of the Earth). Inasmuch as the cosmos is spherical, it must have some center, which, at least from the point of physics, Avicenna identifies with the Earth. (Strictly speaking the Earth is a bit off center in accordance with the demands of the Ptolemaic astronomy, which Avicenna adopts.) 