A theory of responsibility ought to explain what conditions must be satisfied for an agent to be responsible for something, and whether or not ordinary agents can satisfy those conditions, given a plausible understanding of the way our world works. These goals pull against each other: the more stringent the conditions on responsibility, the harder they are to meet, and the greater the chance that we will be unable to satisfy them given a complete scientific picture of the world; the more relaxed the conditions, the easier they are to meet, but the more we may doubt their sufficiency for securing responsibility. My dissertation argues that, perhaps surprisingly, all that is required for an agent to be responsible for an action or outcome is that (1) the action was voluntary; (2) the outcome was at least foreseen; and, (3) the agent had no relevant false beliefs about the nature of what he was doing. While obviously requiring a bit of filling out and defense, these three conditions are both individually necessary and jointly sufficient for responsibility. Moreover, they are conditions that are quite easy to satisfy by ordinary agents. We should be supremely confident, therefore, that so long as we are ordinary agents, we can be responsible for the things we do.