Frankfurt-Type Cases and the Necessary Conditions for Moral Responsibility

It is commonly thought that there are a number of necessary conditions for an agent to be morally responsible for what he does. It seems that moral responsibility requires the agent to have a certain kind of control over his behavior and know that he does. Frankfurt-type cases are designed to show that the principle of alternate possibilities is false and save the possibility of moral responsibility in the face of the possible truth of causal determinism.