Philo Judaeus and Hugo Grotius’s Modern Natural Law

Hugo Grotius is commonly accepted as the first modern natural law theorist, yet Grotius’s definition of natural law was not new and what, if anything, was “modern” about his natural law remains a subject of debate. This paper suggests that a key to the novelty of Grotius’s natural law may be in the prominent role Philo Judaeus, cited 114 times in The Laws of War and Peace, played in Grotius’s natural law theory. Philo’s natural law is explored, and Philo’s connection between will and reason, among other aspects of his thought, are found to have contributed to Grotius’s modern conception.