If any believer in Deity were asked if he thought there ever could arise a substitute for God—that is, some person or power which could take the place of the Almighty—he would doubtless repudiate the suggestion as an absolute impossibility. And yet mortals have in general been believing in a substitute for God without realizing it, and suffering because of their ignorant, mistaken belief.
Every argument of evil is an argument that some power or presence has risen up which has become a substitute for good, God, and that the substitute is more real and more powerful in the lives of men than the original One. We all need to see this claim of evil, and so be better able to master it. Where does evil claim to make this substitution? In your consciousness and mine. There is no other place where it claims to work, and so there is no other place where the battle with it can be fought and won.
Mortal mind, the basic evil, says that the mortal material sense of mind is the only mind; that it embodies and expresses itself in a universe of material things and matter-embodied mortals; that it impels and controls all animate forms of matter with material thoughts, impulses, emotions, and forces, making them live for a short time and then die. Life, it says, is a sequence of material thoughts and sensations, some alluring and pleasurable, some repulsive and painful. Further it claims to equip mortals with material sight, hearing, and feeling and to cause them to see, hear, and feel its material concepts, which constitute its creation and their environment. With the testimony of these senses, its own self-assertion, mortal mind deceives itself and its family of mortals.