Abstract
In 1969 Prof. Frankfurt has introduced a famous class of counterexamples to the Principle of Alternate Possibilities. The principle that states that a person x is only responsible for an action y, if she could have done otherwise than y. In these examples a so called ‘counterfactual intervener’ figures that pre-empts all alternate possibilities counterfactually, that is, without actually intervening. Because this counterfactual intervener only looms passively in the background, x’s moral responsibility for y is not affected, whereas at the same time — by stipulation — x couldn’t have done otherwise than y. Hence, the Principle of Alternate Possibilities must be false.