 A bit of reflection tells us that the goal that we all have is happiness or flourishing (eudaimonia). But what is happiness? The Epicureans’ answer was deceptively straightforward: the happy life is the one which is most pleasant. (But their account of what the highest pleasure consists in was not at all straightforward.) Zeno’s answer was “a good flow of life” (Arius Didymus, 63A) or “living in agreement,” and Cleanthes clarified that with the formulation that the end was “living in agreement with nature” (Arius Didymus, 63B). Chrysippus amplified this to (among other formulations) “living in accordance with experience of what happens by nature;” later Stoics inadvisably, in response to Academic attacks, substituted such formulations as “the rational selection of the primary things according to nature.” The Stoics’ specification of what happiness consists in cannot be adequately understood apart from their views about value and human psychology.