The Demiurge gave it a shape that was fitting and akin to it: for the living thing that was to encompass within itself all living things, the fitting shape would be the shape that includes all the shapes within itself. For this reason it is spherical in form, being entirely equal from the middle to the extremes: he made it rounded off into a circle229 – of all shapes the most complete or perfect and most similar to itself – since the Demiurge thought that similarity was by far more beautiful than dissimilarity. (33b1–8)

After the universal causes (ta aitia ta hola) of the cosmos and the universal composition (holê sustasis), of it and the establishment of an essence that 15 results from its being composed from wholes that are integral to it (ek plêrômatôn holôn), Plato speaks about the shape of the universe – that which surely has been assigned to the universe in accordance with its essence from its creation. This most similar of all the shapes is the fourth demiurgic gift to the universe (5.21 above).

Therefore, though there are also other demonstrations of the spherical shape of the cosmos which are both physical and mathematical and which we shall later examine, for now we shall first consider the Platonic demonstration (apodeixis). This really is a demonstration since the reason why it is (to dioti) is included along with the fact that it is (to hoti). The demonstration is itself triple: the first derives from the One; another from intelligible beauty, and a third from intellectual creation. Or rather, each one of these demonstrations is multiple and is at least triple.

Demonstration from the One

You might say that the Demiurge is one immediately from the One, and you might say that the paradigm is also one, and you might say that the Good is one. From all this you might assume likewise, in the case of the figures, that the figure which is unified to the highest degree is more divine and perfect than that which is not one. For that which the One is among the divine things, and that which the One Living Being Itself is among the intelligible living things, and that which the one Creator and Father is among the demiurges – this role is played in the same way by the sphere among the solid shapes.