 Among the Stoics, the relation between epistêmê and technê is the richest and most focused of all the accounts we have so far considered. That relation is enmeshed in the Stoic account of virtue, in which the two notions of knowledge and craft flow together in forming the science and art of living. Zeno refers to a technê which cures the diseases of the soul (SVF, i.e. Stoicorum Veterum Fragmenta, I 323) and Chrysippus says that practical judgment (phronêsis) is a kind of technê concerning the things having to do with life (SVF II 909). While virtue is compared to a technê, it is also a complete and unshakeable understanding of the universe. It has then some of the features of an epistêmê in Aristotle’s strong sense. Clearly, such a position rests on the basis of peculiar Stoic doctrines. We can begin with the Stoic idea of impulse to action. Diogenes Laertius says that, according to the Stoics, an animal has self-preservation as the object of its first impulse (hormê). So, the first thing appropriate (oikeios) to every animal – including humans – is its own constitution and the consciousness of this. Impulse leads every animal to seek what is appropriate to it and rejects what is not appropriate. In addition, the constitution of adult humans includes reason; so, reason supervenes on what would be purely automatic impulses in other animals. Stoics say that reason is itself the craftsman (technitês) of the adult’s impulses (Diogenes Laertius 7.85–6).