This Article doDespite obvious differences in the Aristotelian and Stoic theories of responsibility, there is surprisingly a deeper structural similarity between the two. The most obvious difference is that Aristotle is (apparently) a libertarian and the Stoics are determinists. Aristotle holds adults responsible for all our "voluntary" actions, which are defined by two criteria: the "origin" or cause of the action must be "in us" and we must be aware of what we are doing. An "involuntary" action, for which we (...) are not responsible, is one that fails to meet either one of these two criteria. Aristotle is a libertarian insofar as he insists that all voluntary actions are "in our power" to perform or not. As determinists the Stoics cannot admit this sort of freedom, but they still consider the agent to be a vital link in the chain of events, so they redefine what is "in our power" as what comes about "through us." The terminology is different, but I argue that these actions, for which the Stoics hold us responsible, are in fact coextensive with Aristotle's voluntary actions. An "impression" is the first necessary condition for action, and is a sort of visual image of the object stimulating one to act. The right sort of impression activates the agent's "impulse," an internal movement of soul or mind, which is the direct cause of action. But impulse is always accompanied by "assent," which is the mind's affirming the truth of the proposition that we ought to go after the object stimulating our impulse. Thus, since assent is a necessary condition for action, we always act knowing what we are doing. This means that all actions caused by our own impulse and assent are by Aristotle's criteria voluntary, where impulse provides the internal origin of the action and assent provides the awareness of what is being done. I conclude that the Stoic and Aristotelian classes of what one is responsible for are coextensive, their criteria defining responsible actions are nearly identical, and the only substantial difference is that Aristotle claims such actions are in our power to do or not do while the Stoics say that such actions are necessitated (by our internal nature as well as external factors). es not have an abstract. (shrink)