Resumen:
This work intends to participate in the debate over the relevance of law in its participants' practical reasoning. The analysis is focused on fundamental rights principles, from the perspective of some of the tenets or preconcepts used by the so called "New Natural Law School". On this conceptual basis, we argue that fundamental rights principles are not mere transcriptions, receptions or "conclusions" from moral principles of justice, but always include what Aquinas called "determination". This thesis is based upon the distinction between the moral and the legal perspectives of analysis of human action. This distinction leads to the conclusion that fundamental rights principles possess a double margin of reference to moral principles of justice on the one hand, and positive principles and rules, on the other.
