According to French philoopher of law Michel Villey (1914-1988), the work of a layer cannot be resumed to applying the law or to follow what the judge can say: a philosophy of nature is intrinsic to the way of determinig fairness; it turns out to become a challenge among different philosophies of nature to define the right. Against legal positivism and Modern natural law, the author provides (in the wake of Villey's thought) to analyse the perenial philosophy of natural law as it was explained in Roman law in the Aristotle/Thomas Aquinas's legal theory
