Abstract

According to the highly controversial “Principle of Alternative Possibilities,” an agent is morally responsible for an action only if he could have done otherwise. In this paper, I will investigate whether Aquinas accepts this principle. I will begin by arguing that if one grants Aquinas’s theory of human action, Frankfurt-style counter-examples do not succeed. For this reason, it is necessary to investigate various texts in order to discover how Aquinas views this principle. Although he does not explicitly discuss it, he does discuss an axiom that is similar to this principle in various ways. I eventually conclude that, even if Aquinas would reject a strict understanding of PAP, he would only demand a relatively common modification of it.