"The Law of Reason in the Kuzari," Proceedings of the American Academy for Jewish Research, Vol. 13 (1943). Reprinted in Persecution and the Art of Writing.
Every student of the history of philosophy assumes, tacitly or expressly, rightly or wrongly, that he knows what philosophy is or what a philosopher is. In attempting to transform the necessarily confused notion with which one starts one’s investigations, into a clear notion of philosophy, one is confronted sooner or later with what appears to be the most serious implication of the question “what a philosopher is,” viz. the relation of philosophy to social or political life. This relation is adumbrated by the term “Natural Law,” a term which is as
indispensable as it is open to grave objections. If we follow the advice of our great medieval teachers and ask first “the philosopher” for his view, we learn from him that there are things which are “by nature just.” On the basis of Aristotle, the crucial question concerns then, not the existence of a ius naturale, but the manner of its existence: is” it in the sense in which numbers and figures “are,” or “is” it in a different sense? The question can be reduced, to begin with, to this more common form: is the ius naturale a dictate of right reason, a set of essentially rational rules?