A human being, says Wojtyla, fulfils himself himself through performing good actions and he destroys both his essence and his existence (becoming, "fieri") through doing evil actions. Therefore it is of utmost importance to cognize what is good and what is evil. Aou whole experience tells us that it is not easy because lying (not telling the truth) is an immanent property of evil: evil lies about itself that is good and it lies about good that it is evil. Having observed this immanent property of evil, we make an attempt to find some forms and sources of evil's lies about good and evil. Finally, following the thought of John Paul II, we point out to a realistic philosophy of being as a basis for effective coping with the problem.Byt ludzki,...