The Author’s aim is to highlight the limits of monist metaphysics which underpin the paradigm of Secular Humanism. In fact, all forms of monism consider good and evil either as internal momentums to the logic of development of the world, or as mere illusions within the evolutionary process. Can tragedies as the Holocaust be interpreted by such a monistic approach? The distinction between ‘polar opposition’ and ‘logic of contradiction’ is introduced by Romano Guardini. This is based on a creationistic metaphysic and it is useful to show that our practical-moral investigation is legitimated only by a theist approach. By considering good and evil as two aspect with mutual implications, monistic logic risks to weaken both freedom and human responsibility within human history.
Keywords: Ethics, metaphysic, monism, theism, evil.