Abstract

This paper will study the universality of natural law that Thomas Aquinas explains in Sententia Libri EthicorumV. In the 5th book of the Nicomachean Ethics, Aristotle tells the difference between natural law and positive law in the context of politic law. This reference point raises the question about the naturalness of the justice rules within the political society. Especially when it comes to the variability inherent in practical matters. Thomas, by contrast, appeals the first principles recognized by practical intellect in order to support the universality of natural law. The comparison among the Aristotelian and Thomistic position on the universality of the natural law, would reflect doctrinal overcomings, continuities or ruptures between different authors that examine, however, a common topic.