It is indeed my opinion now that evil is never “radical,” that it is only extreme, and that it possess neither depth nor any demonic dimension. It can overgrow and lay waste the whole world precisely because it spreads like fungus on the surface. It is “thought-defying,” as I said, because thought tries to reach some depth, to go to the roots, and the moment it concerns itself with evil, it is frustrated because there is nothing. That is its “banality.” Only the good has depth and can be radical.
Hannah Arendt (2000). “The Portable Hannah Arendt”, Penguin Group USA