Written in 1779 by the playwright and philosopher Gotthold Lessing, Nathan the Wise ranks among the most powerful arguments for religious tolerance in the entirety of the eighteenth century. Germany in the age of Enlightenment was still trembling from the confessional disputes of earlier times. The Reformation motto “cuius regio, eius religio” (where the prince reigns, so too his religion) had not put an end to strife amongst Lutherans, Calvinists, and Catholics. But Lessing’s play extended the hand of tolerance even beyond the Christian fold, to Judaism and Islam. In a brilliant feat of displacement, he removed the dramatic action from the Germany of his own day and set his characters in a half-imaginary Jerusalem in the midst of the Third Crusade, where Muslims and Christians scramble for dominion of the Holy City. The play’s hero is the eponymous Nathan, a pious Jew who keeps a household along with his adopted daughter and her Christian maidservant. The critical heart of the play is the confrontation between Nathan and Saladin, the Egyptian sultan who rules the land. Saladin presents Nathan with a challenge: of the three monotheistic religions, only one can be true. But surely a man as wise as Nathan does not obey mere accidents of birth and circumstance. If he remains a Jew, it must be with good reason. Saladin therefore asks that Nathan justify his faith.

Nathan is at first perplexed—he thought Saladin had summoned him only for a loan—but he marshals his wits and explains himself with the following parable. There was once a man who possessed a ring with miraculous properties. Whosoever wore the ring would be beloved of God and men. When the man died, the ring passed through the generations until it fell into the hands of a father with three sons. Since he loved all his sons equally, he sent for a jeweler to fashion two more rings that were in outward appearance identical to the first. The father gives a ring to each of his three sons and promptly dies, leaving them to puzzle over the question of which is genuine. A quarrel breaks out, and they present their case to a judge, each of them swearing the genuine ring is his alone. The judge reminds them that the true ring had the power to make its possessor beloved of God and men. But in their quarrel each brother now hates the other. The sly judge concludes that no ring could be the original—it must have been lost. He offers an alternative: each son should be permitted to believe that his own ring is the true one. After all, it is possible that the father could not tolerate “the tyranny of just one ring.” The judge admonishes the sons to model themselves after their father in unprejudiced affection, each to strive to outdo his brothers in benevolence. Some day, maybe in a “thousand thousand years,” the magic hidden in the jewel will reveal itself when a wiser judge sits at the bench.

Saladin is so moved by this parable that he declares Nathan his everlasting friend. Lessing borrowed the rudiments of the ring parable from Boccaccio’s Decameron, but he was also a spirited advocate of philo-Semitism in an era when Jews had not yet been granted civil rights, and he modeled the character of Nathan on his friend, the Jewish philosopher Moses Mendelssohn. The rest of his play involves a series of increasingly implausible plot twists that lead to a startling revelation: it turns out that Nathan’s adopted daughter is a Christian by birth, and the Knight Templar who wishes to marry her is actually her brother. It is then discovered that they are both children of a Muslim knight who was the brother of Saladin. The characters all embrace as the curtain falls. These days most audiences are too cynical to accept the didacticism of an Enlightenment-era drama: the revelations that unite the characters in happy consanguinity at the play’s denouement come with a real thud. This makes it all the more important that we recognize the philosophical radicalism at its core.

The play was a medieval lesson for modern times. Its crucial lesson is that, notwithstanding all the various historical and cultural differences that separate religions from one another, they are in essence the same. For those who are not blessed with a higher wisdom, that sameness will remain obscure. But for those who are philosophers like Lessing himself, the variations will seem unimportant, and the essential sameness of ethical aspiration will shine forth. The ring parable can mislead us because it tells us of three rings that look identical, which the monotheistic religions do not, at least in their externals; but Lessing was actually trying to tell a story about an inward resemblance that survives the confusing facts of outward dissimilarity. Laws and stories and practices do not matter in the end. All that matters is the common philosophical truth that lies at their core. We grow intolerant when we take notice only of the outward forms, but the truly wise will discern the unity within plurality.

"We grow intolerant when we take notice only of the outward forms, but the truly wise will discern the unity within plurality."

In a remarkable and important book, Carlos Fraenkel characterizes Lessing as one of the late exponents for an intellectual tradition of philosophical religion that stretches as far back as late antiquity. This is a tradition that united pagan thinkers such as Plato with Christians (Origen and Eusebius) and Muslims (Al-Fārābī and Averroes) and Jews (Philo and Maimonides) in a shared philosophical vision, according to which historically distinctive religions should not be understood in the literal sense. They must be interpreted instead in allegorical fashion, so as to grasp their higher and purely rational content. This allegorical content is far from self-evident. But those who are incapable of philosophizing, or have not yet arrived at the requisite intellectual maturity, are not lost: the historical forms of a given religion offer just the sort of moral and political instruction most of us need if we are to conduct our lives with virtue and for the common good. Only the philosopher will understand that the historical forms have an educative function.