Previous versions of our paper on legal principles have been subjected to a number of criticisms, most of them expressed orally in several seminars where we had the chance to discuss our ideas.1

We will try to reply to both critics. It should be noted at the beginning that both Peczenik and Prieto criticize the central pillars of our contribution, and that in their texts — with obvious differences of emphasis — we can also find the basic tenets of the critiques voiced in oral discussions by other legal philosophers. Thus, trying to answer to their objections will be an excellent testing ground for us.

As we understand it, the core of Prieto's and Peczenik's critiques can be divided into the following two points: a) one refers to our understanding of mandatory legal rules (action rules or end rules) as peremptory reasons and to our idea that such rules differ from principles in the strict sense in that the former present cases in 'closed' form while the latter present them in 'open' form; b) the other refers to our conception of principles in the strict sense as norms requiring full compliance, that is, norms that do not allow compliance by degree. One could think that a) contains at least two different questions, but we believe that in our presentation as well as in the critiques by Prieto and Peczenik we are dealing rather with two different aspects of one and the same question, because the fact that rules can function as peremptory reasons im­plies, as a necessary condition, that they determine their conditions of applica­tion in 'closed' form.

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