Grotius’s theory of the foundations of law and morality follows a sort of middle way between rationalism and voluntarism. Grotius, far from both extremes, defends both the normative force of the will and the directive power of practical reason. On this basis, he explains that reason serves as the formal cause of law and the will as the efflcient cause. Now, the command of the will alone is not yet valid as a law. It must conform to reason. Reasoning so, Grotius places himself within the scholastic-Aristotelian tradition. Accordingly, he holds the primacy of reason over the will and defends the eminently practical, i.e., non-mathematical, character of morality and law.