In this paper, I present a novel argument for scepticism about moral responsibility. Unlike traditional arguments, this argument doesn't depend on contingent empirical claims about the truth or falsity of causal determinism. Rather, it is argued that the conceptual conditions of responsibility are jointly incompatible. In short, when an agent is responsible for an action, it must be true both that the action was non-accidental, and that it was open to the agent not to perform that action. However, as I argue, an action is only non-accidental in those cases where it isn't open to the agent not to perform it.