Hard determinists like d'Holbach believe that freedom can be imagined due to the fact that all actions are caused. Ayer thinks that the appropriate contrast to freedom is constraint, and although all constrained actions are caused, it does not follow that all caused actions are constrained. He argues that determinism is difficult to accept because of the moral agency we feel we "do otherwise" and the fact that we feel morally responsible for our actions. Compatibilists generally believe that humans have confused causation and constraint. Causality, for Ayer, is “when an event of one type occurs, an event of another type also occurs” (283). But constraint is what truly determines our