If you have ever wondered what philosophical work(s) a 16th century Reformed theologian read or would recommend to his readers or students, you will no doubt be interested in the following. Girolamo Zanchi, an exiled Italian Christian and professor of Divinity at the University of Heidelberg in the late 16th century, notes in his influential work De Tribus Elohim (1572) that all of the most eminent ancient philosophers held to the same opinion concerning the unity of God. Whether Orpheus, Homer, Sophocles, Pythagorus, Socrates, Plato, Aristotle vel alia, all were monotheists. For those wishing to read more concerning the unified voice of the philosophers, Zanchi says, “let them read Augostino Steuco’s On Perennial Philosophy.” 1
For those who have never heard of Steuco or the concept of “perennial philosophy” the idea is fairly simple. Steuco argues, based on the philosophical work of Renaissance philosophers such as Marsilio Ficino and Giovanni Pico della Mirandola, that despite the variety of solutions posed by a veritable multitude of philosophers, all were inspired by the same spirit of wisdom. Though philosophers often disagree in fundamental ways, the truth that one finds in their writings points to one fairly consistent system of thought, which is contained in its purest form in the doctrines of Christianity. Steuco says:
[T]here must always have been one wisdom, whether handed down by succession or derived by conjecture and assessments, to recall each of them and compare them with the true; [and therefore this work] has the title Conformationes or On the Perennial Philosophy. For since there is one heavenly religion, consisting in excellent piety and doctrine, whoever will may understand that it has been the same ever since the human race began – either nature pointed it out, or revelation came to the rescue – formerly somewhat obscure and confined to a few, afterwards shining forth in all radiance, and blazing in the whole world. Seeing these traces, these remnants of wisdom, we believed they had been as it were the rays of a light greater in the early ages, and later most great; and thus that all things faced towards one truth. 2
Steuco, who published De perenni philosophia in 1540, was an apologist for the Roman Catholic church, librarian at the Vatican, and a presiding member of the Council of Trent. So, his defense of perennial philosophy is not free from polemic, yet it was considered by Zanchi and many other Protestant theologians to be a valuable work, precisely because of its potent defense of Christian doctrine and its use of rare historical sources. 3 This is why Zanchi recommends the book to his readers.