Until now the totalitarian belief that everything is possible seems to have proved only that everything can be destroyed. Yet, in their effort to prove that everything is possible, totalitarian regimes have discovered without knowing it that there are crimes which men can neither punish nor forgive. When the impossible was made possible it became the unpunishable, unforgivable absolute evil which could no longer be understood by the evil motives of self-interest, greed, covetousness, resentment, lust for power, and cowardice; and which therefore anger could not revenge, love could not endure, friendship could not forgive. Just as the victims in the death factories or the holes of oblivion are no longer "human" in the eyes of their executioners, so this newest species of criminals is beyond the pale even of solidarity in human sinfulness.
It is inherent in our entire philosophical tradition that we cannot conceive of a "radical evil." And this is true both for Christian theology, which conceded even to the Devil himself a celestial origin, as well as for Kant, the only philosopher who, in the word he coined for it, at least must have suspected the existence of this evil even though he immediately rationalized it in the concept of a "perverted ill will" that could be explained by comprehensible motives. Therefore, we actually have nothing to fall back on in order to understand a phenomenon that nevertheless confronts us with its overpowering reality and breaks down all the standards we know. There is only one thing that seems to be discernible: we may say that radical evil has emerged in connection with a system in which all men have become equally superfluous."The Origins of Totalitarianism"