Selection (ἐκλογή, selectio) is a key concept in Stoic ethics. It has a prominent role in attempts by Diogenes of Babylon and Antipater of Tarsus in the second century bce to explain and defend the Stoic conception of the good life or human telos. It is a major target of ancient criticism from their contemporary Carneades down to Plutarch and Alexander. And it is central to recent attempts to reconstruct Stoic moral psychology, which take selection to be a distinctive kind of motivation, a species of rational “impulse” (ὁρμή) that differs both from the uniquely virtuous “dispassions” (εὐπάθειαι) of a sage, and from the inherently defective “passions” (πάθη) found in everyone else. So construed, a selection is simply an impulse to act in pursuit of an objective viewed as “indifferent”: not as either good or bad (as in dispassions correctly and passions incorrectly), but as “preferred” or “dispreferred,” on the basis of its “selective” value or disvalue. This intermediate form of motivation, which is common to everyone, sages and others alike, is supposed to help explain how we can make “progress” from vice toward virtue: simply by transforming our passions into selections, that is, by viewing as “indifferent” but “preferred” much of what we ordinarily consider “good.” It also underpins recent accounts of practical reasoning in Stoicism: the correct way to decide what to do is simply to select the available option that promises the greatest selective value.