 Attending to this identification of virtue and practical knowledge is a good way to understand the central Stoic teaching that virtue is living in agreement with nature (SVF III 16). Nature includes not only what produces natural impulses but also the rest of the government of the cosmos, the natural world. The universe is governed by right reason that pervades everything and directs (causes) the way it functions – with the exception of the only rational animals there are, the adult human beings: their actions are governed by themselves, i.e., by assenting to, or withholding assent from particular impulses. Nature is even identified with Zeus, who is said to be the director of the administration of all that exists (DL VII 87–9). Since reason governs the universe for the good, everything happens of necessity and for the overall good. Virtue, then, includes understanding both one’s individual nature as a human being and the way nature arranges the whole universe. At this point, we can appreciate the role of logic and physics as virtue since these entail knowledge of the universe. This understanding is the basis for living in agreement with the government of the universe, i.e., with nature, by making one’s decisions and actions be such as to agree with Zeus’s or nature’s own plans, so far as one can understand what those are.