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
African philosophy in medicine and philosophy, and subsequently became a professor of philosophy at the universities of Halle Halle and Jena in Germany. Kenyan philosopher Henry Odera Oruka has distinguished what he calls four trends in modern African philosophy: ethnophilosophy, philosophical sagacity, nationalistic–ideological philosophy, and professional philosophy. In fact it would be more realistic to call them candidates for the position of African philosophy, with the understanding that more than one of them might fit the bill. (Oruka later added two additional categories: literary/artistic philosophy, such as the work of literary figures such as Ngũgĩ wa Thiong'o, Wole Soyinka, Chinua Achebe, Okot