In this paper it is argued that Frankfurt's and Strawson's defenses of compatibilism are insufficient due to neglected features of the role of alternate possibilities in assigning moral responsibility. An attempt is made to locate more adequately the genuine source of tension between free will and determinism, in a crowding phenomenon in the view of an action which our concept of responsibility has not grown up coping with. Finally, an argument is made that due to the nature of belief we can believe the thesis of determinism only if it is false, lending support to incompatibilism.