The aim of the paper is to examine the nature of moral and legal norms in a broader context: first, taking into account logical and methodological assumptions, second, in the perspective of psychology of emotions and legal policy. The basic subject of the research carried out by Leon Petrażycki was represented by law. Originally, it had a psychological character, not an objective, eternal, and unchanging one. To fully understand the genesis and nature of morality and law, Petrażycki addressed the study of mental phenomena, especially emotional experiences. First, however, he developed appropriate rules of logic and scientific methodology. Then he developed a new classification of mental phenomena, among which the fundamental role is played by bilateral (passive-active) emotions. At some stage, emotions begin to cooperate with cognitive processes, first of all with imaginations. Imaginations of acts, such as theft, betrayal, murder, can cause repulsive emotions, and type imaginations, such as truthfulness, charity, justice can evoke apulsive emotions. On the basis of such associations, judgments are created over time, the content of which becomes a basis for fundamental rules of conduct, that is, for norms. There are two fundamentally different types of norms: moral norms and legal norms. The norms of the first type are imperative and represent the nature of validity (they are obeyed), while the norms of the second type are imperative-attributive and they also always entitle someone to something, i.e. they give someone a right. This division determines a fundamental difference between morality and law.