Dualism, as we have noted, comes in many forms: between mind and body, in-group and out-group, and between the higher and lower instincts between which we must constantly choose. It may be that binary opposition is one of the fundamental ways in which we understand the world. But divide humanity into absolute categories of good and evil, in which all the good is on one side and all the evil on the other, and you will see your own side as good, the other as evil. Evil seeks to destroy the good. Therefore your enemies are trying to destroy you. If there is no obvious evidence that they are, this is a sign that they are working in secret. If they deny it, this is proof that the accusation is true, else why would they bother to deny it? And since they are evil and we are good, they are the cause of our present misfortunes and we must eliminate them so that the good to which we are entitled, the honour we once had and the superiority that is our right can be ours again. That is the pathological dualism that leads to altruistic evil with murderous consequences.