René Descartes, founder of modern philosophy.

Medieval philosophy was dominated by Scholasticism until the emergence of Humanism in the Renaissance. Modern philosophy began in France[citation needed] in the 17th century with the philosophy of René Descartes, Blaise Pascal, and Nicolas Malebranche. Descartes revitalised Western philosophy that had been on the decline after the Greek and Roman eras.[303] His Meditations on First Philosophy changed the primary object of philosophical thought and raised some of the most fundamental problems for foreigners such as Spinoza, Leibniz, Hume, Berkeley, and Kant.


René Descartes, founder of modern philosophy.
During the 18th century, French philosophers produced one of the most important works of the Age of Enlightenment. In The Spirit of the Laws, Baron de Montesquieu theorized the principle of separation of powers, that has been implemented in all liberal democracies since it was first applied in the United States. In The Social Contract, Jean-Jacques Rousseau openly criticized the European divine right monarchies and strongly affirmed the principle of the sovereignty of the people. Voltaire came to embody the Enlightenment with his defence of civil liberties such as the right to a free trial and freedom of religion.
19th-century French thought was targeted at responding to the social malaise following the French Revolution. Rationalist philosophers such as Victor Cousin and Auguste Comte, who called for a new social doctrine, were opposed by reactionnary thinkers such as Joseph de Maistre, Louis de Bonald and Lamennais, who blamed the rationalist rejection of traditional order. De Maistre is considered, together with the Englishman Edmund Burke, one of the founders of European conservatism, while Comte is regarded as the founder of positivism and sociology.
In the early 20th century, French spiritualist thinkers such as Maine de Biran, Henri Bergson and Louis Lavelle, influenced Anglo-Saxon thought, including the Americans Charles Sanders Peirce and William James, and the Englishman Alfred North Whitehead. In the late 20th century, partly influenced by German phenomenology and existentialism, postmodern philosophy began in France, with notable post-structuralist thinkers including Jean-François Lyotard, Jean Baudrillard, Jacques Derrida, Jacques Lacan, Michel Foucault and Gilles Deleuze.