Euler's Letters to a German Princess: Translation and Betrayal – Condorcet's Distortions

As we can see, the story behind the translation of the Lettres is complex, and it has not been fully told. Before pursuing this story further, however, I became distracted by an issue even deeper than that of translation. I learned that there are several examples of textual betrayal in the French editions—in the most widely distributed edition of the Lettres, Euler’s words were systematically abridged for political purposes. 

The most widely-distributed and well-known edition of the Lettres (and the one from which Henry Hunter made the only English translation to date) is probably the third (E343⁴, published in 1787), an edition in which the Marquis de Condorcet played a significant role. Condorcet and Euler at first seem like a wonderful match—a leading scientist and philosopher helping to edit the works of a giant of the previous generation. However, Condorcet’s efforts were not as selfless and honorable as we might expect: he systematically and deliberately edited Euler’s work by excising passages that he didn’t think belonged.

Figure 6. Title page from the 1787 edition of Lettres edited by Condorcet and others. Google Books.

Condorcet’s name is perhaps not as well known in the mathematical or scientific communities as it is to historians. He was a competent but not a great mathematician. His greatest achievements were perhaps quasi-mathematical: he was one of the first people to apply mathematics to understand human behavior. (We still see his name while studying voting theory, for example, as described in the Convergence article, “The French Connection: Borda, Condorcet and the Mathematics of Voting Theory.”) He was an influential figure in the French Revolution and was, in the words of E. O. Wilson, “a complete revolutionary, both anticlerical and republican” [Wilson 1998]. He was committed to the idea of human progress and to creating a “more perfect social order ruled by science and secular philosophy” [Wilson 1998, p. 19]. 

Condorcet’s legacy in Euler’s Lettres came to my attention via an unexpected source. In 1747, Euler published an anonymous tract titled Rettung der Göttlichen Offenbahrung gegen die Einwürfe der Freygeister (E92, Defense of divine revelation against the objections of the freethinkers). Some years ago, Andie Ho translated this work into English [Défense 1805], but in fact, she did much more than this. She also translated a book containing the Rettung as one part [Défense 1805], originally published by Adrien Le Clere (an official printer of the Vatican, based in Paris) in 1805. The Le Clere book includes a brief discussion about how difficult it had been for the publishing house to locate a copy of the Rettung, and then reprints the entire work (in a French translation of Euler’s original German). The anonymous editor of the book follows Euler’s tract with an essay that startled me, and which provided the final piece for my investigations. The essay, “Comparison of the last edition of Euler’s Letters published by de Condorcet, with the original edition,” carefully demonstrates that Condorcet removed, wherever possible, Euler’s references to God, salvation, and scripture. 

That Euler was a devout man is well known; he often used theological arguments to buttress or explain his scientific ones, and he found no conflict in this. Condorcet, however, found these ideas anathema to the ideals of the Enlightenment in general and to the goal of teaching science through the Lettres in particular. He thus removed Euler’s theological references in every letter in which doing so wouldn’t destroy the purpose of the letter. Hunter found and restored some of Condorcet’s excisions, but not all of them. The first letter in which this occurs seems to be Letter 18. By the end of this letter, Euler believed that he had shown that Newton had erred in his theory of light emission from the sun, and concluded with a lengthy philosophical reflection:

If we are prone to such sad mistakes in our research on the phenomena in this visible world, a world which we can sense, how unfortunate would we be if God had abandoned us to ourselves with regards to the invisible world and our eternal salvation. On this important point, a revelation is absolutely necessary to us. We should make the most of it with the greatest veneration; and when this revelation presents us with things that seem inconceivable, we have but to remember the weaknesses of our mind, which strays so easily, even for the visible things. Each time I hear these freethinkers criticize the truths of our religion and even mock it with the most impertinent self-importance, I think and say to myself, “Puny mortals, no matter how lightly you gloss over these things and how many you ignore, they are more sublime and elevated than those on which the great Newton was so grossly mistaken. I hope that Your Highness never forgets this thought; the times when you are in need of it come all too often” [Défense 1805].

This entire passage was cut by Condorcet. In his translation, Henry Hunter, a Scottish minister with no desire to hide Euler’s piety, restored the passage in a footnote at the end of the letter [Euler 1795, p. 82–83]. Hunter, however, didn’t find every passage that Condorcet removed. The first example I can find that Hunter missed occurs in Letter 21. In an attempt to give some meaning to the vast distance to the stars, and the finite speed of light, Euler in his original letter invokes a Biblical reference:

If, at the beginning of the world, the stars had been created at about the same time as Adam, he would not have been able to see even the closest ones for six years; he would have had to wait even longer before discovering the others, since they are even farther from the Earth [Défense 1805].

Condorcet cut this sentence from Euler’s letter, presumably in the belief that reference to figures such as Adam did not befit a scientific work. As noted above, this sentence does not appear in the first English edition [Euler 1795, p. 97]. Nor, according to keyword searches of digitized copies of E343G, E343G², and E343G⁴, is there any mention of Adam in any of the English printings of the Letters except for a brief reference to Adam and Eve at the beginning of Letter 116 (the first letter in volume 2 of each edition) [Euler 1795, vol. 2, p. 1; Euler 1802, vol. 2, p. 1; Euler 1833, vol. 2, p. 1].  

The book published by Le Clere goes on to list dozens of instances in which Condorcet and the other French editors removed passages from Euler’s work. They range from the trivial to the significant, yet their sum total means that the reader who only sees Euler in a later French edition, or in English translation, will end up with a distorted sense of Euler’s thought. 

Condorcet was unapologetic about rewriting Euler’s work. It is interesting and instructive to read his Avertissement at the beginning of the book. (Convergence’s Mathematical Treasures entry for Lettres provides images of this edition’s entire Avertissement.) “Without failing in the respect due to Euler,” Condorcet wrote, “I thought myself at liberty to omit some passages altogether, and to correct the style of others.” He then spent more than a page justifying this, claiming that although it may be unreasonable to expect a non-native speaker to write “a foreign language with classical purity,” some readers who didn’’t already know Euler’s greatness might judge him harshly for this. Wanting to save Euler from such judgment, Condorcet apparently edited his French for style. Having devoted considerable attention to this, he then almost glossed over the changes we discussed above:

As to other retrenchments, they affect, almost all of them, reflections which relate less to the science and philosophy, than to theology, and frequently even to the peculiar doctrines of that ecclesiastical communion in which Euler lived. It is unnecessary to assign a reason for omissions of this description [Condorcet 1787, pp. iii–vi, my translation].