Philosophy is the study of general and fundamental problems, such as those connected with reality, existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational argument. The word "philosophy" comes from the Greek φιλοσοφία (philosophia), which literally means "love of wisdom".

The introduction of the terms "philosopher" and "philosophy" has been ascribed to the Greek thinker Pythagoras. The ascription is said to be based on a passage in a lost work of Herakleides Pontikos, a disciple of Aristotle. It is considered to be part of the widespread body of legends of Pythagoras of this time. "Philosopher" was understood as a word which contrasted with "sophist" (from sophoi). Traveling sophists or "wise men" were important in Classical Greece, often earning money as teachers, whereas philosophers are "lovers of wisdom" and not professionals.

The main areas of study in philosophy today include epistemology, logic, metaphysics, ethics, and aesthetics.

René Descartes (French pronunciation: [ʁəne dekaʁt]; Latinized form: Renatus Cartesius; adjectival form: "Cartesian"; 31 March 1596 – 11 February 1650) was a French philosopher, mathematician, and writer who spent most of his adult life in the Dutch Republic. He has been dubbed the 'Father of Modern Philosophy', and much subsequent Western philosophy is a response to his writings, which are studied closely to this day. In particular, his Meditations on First Philosophy continues to be a standard text at most university philosophy departments. Descartes' influence in mathematics is equally apparent; the Cartesian coordinate system — allowing algebraic equations to be expressed as geometric shapes in a two-dimensional coordinate system — was named after him. He is credited as the father of analytical geometry, the bridge between algebra and geometry, crucial to the discovery of infinitesimal calculus and analysis. Descartes was also one of the key figures in the Scientific Revolution and has been described as an example of genius.

Michel Foucault (French pronunciation: [miʃɛl fuko]), born Paul-Michel Foucault (15 October 1926 – 25 June 1984) was a French philosopher, social theorist and historian of ideas. He held a chair at the Collège de France with the title "History of Systems of Thought," and lectured at the University at Buffalo and the University of California, Berkeley.

Foucault is best known for his critical studies of social institutions, most notably psychiatry, social anthropology of medicine, the human sciences and the prison system, as well as for his work on the history of human sexuality. His writings on power, knowledge, and discourse have been widely influential in academic circles.

In the 1960s, he was associated with structuralism, a theoretical movement in social anthropology from which he later distanced himself. He also rejected the poststructuralist and postmodernist labels later attributed to him, preferring to classify his thought as a critical history of modernity rooted in Immanuel Kant. His project was particularly influenced by Nietzsche, his "genealogy of knowledge" being a direct allusion to Nietzsche's "genealogy of morality". In a late interview he definitively stated: "I am a Nietzschean."