Existentialism is a Humanism

René Descartes (1596-1650) was a French mathematician, philosopher, and scientist. His most famous philosophical work, the Meditations on First Philosophy (1641), is one of the key texts of modern Western philosophy. In it, Descartes employs the method of “radical doubt,” subjecting everything he believes to doubt in order to detect whether his body of putative knowledge contains any self-evident truths. The truth he alights on is what is now known as the cogito, the undeniable fact that if I am thinking, then I exist (“cogito, ergo sum”). Taking the cogito as a first principle and deducing further truths implied by it, Descartes goes on to offer a proof of God’s existence. 

Immanuel Kant (1724-1804) is the central figure of modern Western philosophy. His three most important works, the Critique of Pure Reason (an epistemological work that deals with the conditions and limits of any possible experience and knowledge), the Critique of Practical Reason (an ethical work that argues that morality is grounded in reason), and the Critique of Judgment (a work of aesthetics that argues that aesthetic appreciation is based on disinterested judgment) form a unified system. 

Albert Camus (1913-1960) was a French Algerian novelist, philosopher, and journalist. Born into a working-class family in Mondovi (present-day Dréan), he completed his philosophical education at the University of Algiers, earning the equivalent of an M.A. with his thesis on Plotinus. In addition to philosophy and fiction, Camus also wrote plays, short stories, and essays. His major works include The Myth of Sisyphus, The Stranger, The Rebel, and The Plague. He won the Nobel Prize for Literature in 1957 at the age of 43.