For the past several weeks my lunchtime reading has been from James Gordley's masterful work, "The Jurists: A Critical History" (OUP 2013). I'm up to only chapter 5 which Gordley titles "Ius Naturae et Gentium: The Iusnaturalists." Gordley coined the term iusnaturalists to distinguish the troika of the Dutchman Grotius, the German-Lutheran Samuel Pufendorf, and the Frenchman Jean Barbeyrac from their jurisprudential predecessors, the Late Scholastics and the Humanists.
The Late Scholastics, like Franceso de Vitoria and Francisco Suarez, had reworked the Medieval understanding of Roman law in terms of Aristotelian philosophy as mediated through the theology of Thomas Aquinas. In reaction, the later Humanists took the motto of ad fontes and applied it to Roman law to create a pure text of Justinian's Code and to understand that text in light of contemporary Roman literature. The Late Scholastics were legal philosophers. The Humanists were philologists.
By the seventeenth century, especially in Northern Europe, both Scholasticism and Humanism had run their courses in fields apart from theology. Beginning with Grotius, a new project, neither legal philosophy for the jurist nor a repristination of a legal system from the distant past, took root. Instead,
[The iusnaturalists] tried to realize the ideal [of law as a Ciceronian ars, an art comprehensible by all educated men, not only jurists] by borrowing the conclusions of the late Scholastics but unmoored from the Aristotelian and Thomistic philosophical principles that had anchored them.
The iusnaturalists borrowed much from the Late Scholastics. The Late Scholastics, however, tried to work out with precision the implications of ideas that they had taken from Aristotle and Aquinas, while the iusnaturalists did not. They were not writing for those with technical training in Aristotelian philosophy. Grotius, like Cicero and the humanists, wanted an account of law that could be part of a non-specialized liberal education.Although consciously separating themselves from the Late Scholastic tradition, and utilizing the results of the philological efforts of the Humanists, the iusnaturalists were not secularists. Unfortunately,
the higher principles from which they supposedly derived their conclusions about property, unjust enrichment, tort, and contract, as well as international law, were far from clear.Why not? It comes down to a difference in purpose or goal:
The Late Scholastics were trying to give a rigorous and consistent philosophical account of law. [The iusnaturalists] wanted a simple account. ... The price they paid for simplicity was that the meaning of these principles became obscure.While the iusnaturalists often referred to received Christian theological doctrines, they didn't make much use of them because to have done so would have undermined their immediate goals. And while the iusnaturalists frequently took over the philosophical conclusions of the Late Scholastics, they avoided the arduous task of explicating them.
Notwithstanding the intentions of the iusnaturalists, however, the effect of the sublimation of philosophical and theological foundations to simplicity was to make easier a transition to a secularized understanding of law.