Libertarianist concept of free will is based on the principle of alternate possibilities - standpoint which presupposes that an agent has moral responsibility only if, in the given circumstances, he could have done otherwise. The author of this paper tries to review this key principle of libertarianism, and to determine whether the access to alternate possibilities represents necessary or sufficient cause for the assessment of moral responsibility, or neither of that. Finally, based on the consideration of famous Frankfurt’s and Austin-style examples, in this paper is defended a sort of compatibilism, and the main advantages of that kind of free will concept over libertarianism are emphasized.