The mutual attractions of the abbot Sigorgne

This ecclesiastic, who popularized Newton’s ideas, is an example of the spirit of the Enlightenment that deserves to be brought out of oblivion, according to the mathematician Etienne Ghys.

Carte blanche. You probably don’t know Abbot Sigorgne. However, he was the subject of a fascinating symposium on October 4 and 5 in Mâcon, bringing together specialists in the history of science and literature. Born in 1719 and died in 1809, in Mâcon, it is difficult to classify him: mathematician, physicist, writer, man of the church? In our society of immediacy, we must always remember the importance of historical research to better understand our contemporary world, which owes so much to the Enlightenment.
In the 18th century, the battle raged between the English, supporters of Newton’s theory of gravitation, and the French, supporters of Descartes’ theory. According to Descartes, space is filled with an unknown fluid, forming whirlpools of all sizes that drag the planets in their course. According to Newton, space is empty and the bodies are subjected to mysterious forces of mutual attraction that act instantaneously, even if the distances between them are considerable.

As we know, Newtonians will win the battle against the Cartesians (while waiting for Einstein’s arrival with his theory of general relativity). Voltaire will play an important role by writing his wonderful Elements of Newton’s Philosophy (1738) in an almost journalistic tone. Newton will penetrate scientific France thanks to the translations and commentaries of Emilie du Châtelet. But it was Abbot Sigorgne who allowed Newton to enter university teaching by writing his Newtonian Institutions in 1747. Of course, Sigorgne is not as well known as Condorcet, d’Alembert, Voltaire or Rousseau, but history is not reduced to celebrities, and it is important to look at a less well-known Mâconnais than Antoine Griezmann.

Reconciling Descartes and Newton

Our abbot is a man of the Enlightenment, open to dialogue. He will exchange about a hundred letters with Georges-Louis Le Sage, a Geneva physicist, who will try to convince him that it is possible to reconcile Descartes and Newton. According to Le Sage’s theory, space is filled with microscopic particles that partially penetrate bodies by bouncing off atoms. That made it possible to explain the mysterious force of gravitation whose origin Newton himself admitted not to understand. However, this beautiful theory of The Wise Man was not successful.
Sigorgne is also a teacher. Several letters from Turgot show that he had not forgotten his teacher and that he could seriously discuss the Newtonian attraction and the geometry of ellipses or hyperbolas. Happy times when rulers knew geometry! On the other hand, fifty years later, it seems that Lamartine did not really benefit from his mathematics lessons.
Of course, all this is mixed with intense theological debates: how to reconcile Reason and Faith? The abbot, for example, violently attacked Rousseau’s Lettres écrites de la montagne (1764) by publishing the Lettres écrites de la plaine (1764), or the defense of miracles against the philosopher of Neuf-Châtel (1766).
At the end of his life, Sigorgne judged that “high scientific works no longer suited his age”, and wrote a collection containing a large number of fables, in the manner of La Fontaine. The manuscript was recently found in the archives of Mâcon. A literary historian made a detailed analysis of it and came up with a very nice idea: in collaboration with a school teacher, she worked on some of these fables in a class of CM1-CM2 in a neighboring village. A video maker staged the whole thing and produced a nice film. What an emotion to see in 2019 children declaiming forgotten texts, as if echoing the Age of Enlightenment!