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
Islamic philosophy and religion. The social philosopher and Ash'ari polymath Ibn Khaldun (1332–1406) was the last major Islamic philosopher from Tunis, North Africa. In his "Muqaddimah", he developed the earliest theories on social philosophy, in formulating theories of social cohesion and social conflict. His "Muqaddimah" was also the introduction to a seven volume analysis of universal history. Ibn Khaldun is considered the "father of sociology", "father of historiography", and "father of the philosophy of history" by some, for allegedly being the first to discuss the topics of sociology, historiography and the philosophy of history in detail. Islamic philosophy found an audience with