It is proposed in this paper to consider, largely from the standpoint of the philosophy of religion, one religious idea: the idea of a power or powers of evil, or, to grasp the whole in one symbol, the idea of the Evil One. Such a discussion should have its interest. The idea of the Evil One, or the Devil as we commonly call him, is perfectly familiar to the average person. There is no need therefore of any elaborate definings. One has only to note that by the Evil One is meant that force or power which is constitutionally—on principle, one might say, if that phrase did not seem a bit out of place—the champion and fosterer of chaos and discord and calamity, of evil and harm and wickedness in general. Or, to put it negatively,—as we perhaps more often think of it,—the Devil is the leader of the opposition as regards the hopeful, the progressive, the divine, with all the meaning which may be packed into that last word.