 The second area is moral responsibility, our ability to be justifiably subject to praise and reward, or blame and punishment for what we do. Aristotle gives an extended analysis of voluntary actions, ones for which a person is responsible. He asserts that humans are the origin of their voluntary actions, and that we have the ability to do otherwise than we do. But the problem of free will and determinism does not obviously arise in Aristotle’s discussion, because he does not consider whether moral responsibility is compatible with causal determinism, as a general thesis. Instead, he considers another threat to our responsibility, which we may dub “psychological determinism”: that our actions are automatically elicited by a combination of our psychological states, such as our desires and character traits, in conjunction with perceptual input, such that we are not really in control of what we do. In response, Aristotle argues that we are in control of our character, because it is a result of our earlier voluntary actions. Epicurus agrees with Aristotle that we are in charge of our character, which results in our actions, and he also contends that to argue that people are not responsible for their actions is self-refuting. Finally, Epicurus believes that causal determinism is incompatible with human freedom, and he introduces an indeterministic atomic motion, the “swerve”, to combat this threat—although how it is supposed to do so is unclear. The Stoics, on the other hand, affirm that every single event is causally determined by God in accordance with his providential plan, and they try to show how what we do is under our control in such a world. The later Aristotelian Alexander of Aphrodisias reacts to the Stoics by building an Aristotelian theory on which the ability to do otherwise is required for moral responsibility, and such an ability is incompatible with causal determinism. Plotinus, who takes himself to be following Plato, incorporates Stoic elements into his own theory of freedom, but his deep disagreements with Stoic metaphysics lead him to reject much of what they say about fate.