 Consider, for example, Pereboom’s famous “four-case” argument. The argument sets out three examples of actions that involve manipulation, the first of which features the most radical sort of manipulation consistent with all the leading compatibilist conditions, each progressively more like the fourth, which is an ordinary case of action causally determined in a natural way. The challenge is for the compatibilist to point out a relevant and principled difference between any two adjacent cases that would show why the agent might be morally responsible in the latter example but not the former. Here, for instance, is the second case: