The legal-moral obligation or binding nature of a legal norm is opposed to the juridico-moral authority or the authority of its author (actor) or another source. The idea of authority has been clarified by contemporary legal theorists such as Raz and Hart by reflecting on the types of reasons to be given to potentially acting subjects through the exercise of practical authority. The relevant type of practical reason has been variously described as exclusive, mandatory or preventive and independent of content. The basic idea is that subjects are asked to treat the reason advanced (e.g., a legal provision or court order) in their deliberations on choice and action as a reason that does not simply add to the reasons they already have for acting in one way or another, but rather excludes and replaces some of those reasons. And this exclusive, coercive or preventive power is not due to the inherent appeal of reason for reason`s sake, but is treated as decisive for the status of its author or another source as someone who has the right to obey, fulfilled – for example, by his role in a constitutional system of government to solve the problems of coordination of a political community. See, for example, Raz 1986, 35-69. That substantive independence from the relevant reasons implies their obligation of presumption. The admissibility of this presumption derives from the dependence of coercive, preventive or exclusionary force on a background of presumption of fundamental human needs and goods and fundamental moral principles and norms, a context which, when a reason allegedly advanced (postulated) is in sufficiently clear conflict with those existing needs, goods, principles or norms, His exclusion Force is exhausted or defeated and the presumed commitment is defeated. For as far as  is concerned, what requires the primacy of law and not of men is the institution of the legal system, a corpus iuris, and what implies a principle of morality (natural law) or ius gentium would be an adequate rule of law, but this is not yet part of our law – much less a simple “policy” made law. by being “prudent” or “effective” – unless its content, concept and form are formed, whether in judicial or legal thinking, case law or legislation, in such a way as to be consistent with other parts (especially adjacent parts) of our law. It should be noted that classical naturalism is compatible with giving man an essential role in the production of laws.
While the classical naturalist seems committed to the assertion that the law necessarily encompasses all moral principles, this assertion does not imply that the law is exhausted by the set of moral principles. There will always be coordination problems (such as which side of the road to drive on) that can be solved in a variety of ways that are compatible with moral principles. Thus, the classical naturalist does not deny that man has considerable discretion in the creation of natural law. On the contrary, it simply asserts that this discretion is necessarily limited by moral norms: legal norms promulgated by men are valid only if they are compatible with morality. In the 16th century, the Salamanca School (Francisco Suárez, Francisco de Vitoria, etc.) developed a philosophy of natural law. But Thomas Aquinas is also a theorist of natural law. According to him, a human law (that is, what is proclaimed by men) is valid only to the extent that its content corresponds to the content of the natural law; As Thomas Aquinas says, “Human law has as much of the nature of law as natural law. But if it departs from the natural law in any respect, it is no longer a law, but a perversion of the law” (ST.
I-II, Q.95, A.II). To paraphrase Augustine`s famous remark, an unjust law is really not a law at all. Once the determination has been validly made and meets the criteria of validity established by or under the constitutional law of the legal system concerned, it modifies the existing legal situation by introducing a new or amended rule of law and a rule of law. The new or modified rule of law gives judges, other public servants and citizens a new or modified reason to act (or to refrain). The fact that the new or amended rule depends on the de facto social source constituted or used by the act of determination does not mean that a normative reason (a “should”) flows illogically from a mere fact (an “is”). On the contrary, the new or modified rule is normative, directive and (when this is its legal meaning) convincing, because this social fact can be the second premise of a practical syllogism, the first premise of which is normative: “There should be a maternity in this city”, “People should be protected from murderous assault”, “People should be required to participate in the public expenditure of appropriate government functions”, “Victim of personal injury, theft, breach of contract, negligence, etc. should be compensated”, “Road traffic should be regulated to reduce harmful collisions”, etc. The moral normativity of the principle is reproduced in the more specific rule created by the determination, although the latter is not a consequence of the first. Theorists such as the English philosopher John Locke believed that if a ruler violates natural law and does not protect “life, liberty, and property,” the people have the right to overthrow the existing state.