Letters on the English author of "Novum Organum" and father of experimental philosophy. Letter 13 is about John Locke and his theories on the immortality of the soul. Letter 14 compares British philosopher Isaac Newton to French philosopher René Descartes. Upon his death in 1727, Newton was compared to Descartes in a eulogy performed by French philosopher Fontenelle. While the British did not appreciate this comparison, Voltaire argues that Descartes, too, was a great philosopher and mathematician. Letter 15 focuses on Newton's law of universal gravitation. Letter 16 talks about Newton's work with optics. Letter 17 discusses Newton's work with geometry and his theories
20th-century French philosophy highly influenced by biology, particularly Darwin's "Origin of Species", which was released the year of Bergson's birth. This led Bergson to discuss the 'Body' and 'Self' in detail, arguably prompting the fundamental ontological and epistemological questions to be raised later in the 20th century. Bergson's work was a major influence on Gilles Deleuze, who wrote a monograph on him ("Bergsonism") and whose philosophical analyses of cinema ("" and "") develop his ideas. Following debates concerning the foundation of mathematics around the mathematician and philosopher Henri Poincaré (1854–1912), who opposed Bertrand Russell and Frege, various French philosophers started working on philosophy