This chapter studies the intersection of biology and cosmology from the angle of the thesis that the cosmos is intelligent in the sense that it is an agent capable of thinking, which is part of their more general thesis that the cosmos is an animal. The thesis that the cosmos is intelligent is argued for by the Stoics through different families of proofs.The present chapter focusses on one of them, called ‘F1’,and its relation to the proof of the intelligence of the cosmos in Plato, Tim. 30a2–c1. The argument-structure common to the members of F1 is (a) the intelligent is better than the unintelligent but (b) the cosmos is better than everything else; therefore, (c) the cosmos is intelligent. I argue that this argument-structure is borrowed from the Timaean proof but that, in contrast with the Timaean proof, F1 is based on a teleological theory that I call ‘cosmocentrism’, according to which the cosmos is a beneficiary, and the ultimate beneficiary, of everything that exists within it. Plato accepted cosmocentrism, but he did not use it to argue for the intelligence of the cosmos. This family, therefore, introduces a major innovation in ancient cosmological thinking.