Induction, abduction and deduction are basic concepts in general epistemology as well as in the epistemology of legal sociology. Fittipaldi uses induction to refer to a kind of brainstorming aiming to the discovery of a new nomological hypothesis; abduction to refer to the set of heuristic tools whereby a researcher tries to single out which of the already available nomological hypotheses can be used in order make a hypothesis of retrodictive explanation, deduction to refer to the way a researcher can use some of the already available nomological hypotheses in order to predict future events. The author holds that both semantic and teleological comprehension (semasiologisches and teleologisches Verstehen) can be used among others as abductive methods by a legal sociologist who desires to single out which regularities, if any, feature the behaviour of chess players. Nonetheless in some cases even observation alone can play an abductive role. This happens when a legal sociologist has the choice between two different nomological hypotheses which both seem able to explain the very same fact. In this case he might try to deduce from these two nomological hypotheses, respectively, two different predictions about future behaviours of the same or similar chess players in order to try to discover which one is the wrong one. The abductive function of such an elimination procedure allows Fittipaldi to show that Ross’s analysis of this situation contains some epistemological misunderstandings which may endanger some of the main ideas of Scandinavian legal realism.