Seeing that socio-legal theory has produced a number of compelling grand theories about law’s development as a body of knowledge, this contribution analyzes legal evolution on the micro-level of decision-making in concrete cases. To that end, law finding is reconstructed as a three stage process of reason-based rule-construction. Legal evolution is argued to stem from the argumentative jumps that are made in this process in order to use what is initially drawn from the body of legal knowledge in new cases. (...) These jumps are justified by additional reasoning that plays a crucial role in that it brings new information to the law finding process. It is explained how this new information gets incorporated in the body of knowledge as a result of discursive maneuvers of legal practitioners. (shrink)