The problem of the relationship between “reason” and “law” has two different meanings depending on whether the first or the second of the two terms is considered to be the most important one. These two different meanings are revealed in the expressions “law of reason” and “legal reason,” respectively. In the first expression, “reason” is meant in its strong sense, that is, the faculty of grasping the essence of things, while in the second, “reason” is meant in a weak sense, (...) the ability to reason (calculate, infer, discuss). “Law of reason” and “legal reason” correspond to two different moments of the legal universe, the creation and, respectively, the application of law. Strong reason is that which discovers the rules to be obeyed, while weak reason is that which applies rules to an actual case. The first is legislating reason, while the second is judging reason. The main topic of the debate from the Greeks to Kant was that of legislating reason. Nowadays, instead, scholars in the field are interested in judging reason. Historicism and positivism mark the end of faith in the existence of rules which are objectively just, and which may be recognized by human reason. By now we have learned to do without the eternal truths in the knowledge of the world. However painful it may be, we are forced to resign ourselves to do without evident truths in ethics, as well. (shrink)