Abandoning the study of John Stuart Mill only for that of Lachelier, the less she believed in the reality of the external world, the more desperately she sought to establish herself in a good position in it before she died.
(Marcel Proust, In Search of Lost Time iv ,438)
The work of Henri Bergson (1859–1941) is considered the division point between nineteenth and twentieth century French philosophy. Essentially, despite his respect for mathematics and science, he pioneered the French movement of scepticism towards the use of scientific methods to understand human nature and metaphysical reality. Against Durkheim, he argued that Positivism was not appropriate as a basis for the philosophy of science. Unlike later philosophers, Bergson was highly influenced by biology, particularly Darwin's Origin of Species, which was released in the year when Bergson was born. This led Bergson to discuss the 'Body' and 'Self' in detail, thus preparing the fundamental ontological and epistemological questions that were raised by French thinkers later in the 20th century. Bergson's work was a major influence on Gilles Deleuze, who wrote a monograph on him (Bergsonism).
The mathematician and philosopher Henri Poincaré (1854–1912) opposed Bertrand Russell and Frege, and unleashed academic debates concerning the foundation of mathematics. Various French philosophers started working on philosophy of science, among them Gaston Bachelard, Jean Cavaillès (1903–1944), and Georges Canguilhem. The latter had a strong influence on Michel Foucault, Gilles Deleuze, and Jules Vuillemin. In his introduction to Canguilhem's The Normal and the Pathological, Foucault wrote:
Take away Canguilhem and you will no longer understand much about Althusser, Althusserism and a whole series of discussions which have taken place among French Marxists; you will no longer grasp what is specific to sociologists such as Bourdieu, Robert Castel, Jean-Claude Passeron and what marks them so strongly within sociology; you will miss an entire aspect of the theoretical work done by psychoanalysts, particularly by the followers of Lacan. Further, in the entire discussion of ideas which preceded or followed the movement of '68, it is easy to find the place of those who, from near or from afar, had been trained by Canguilhem.
Later in the century, Bruno Latour (b. 1947) developed the actor-network theory, which is a distinctive approach to social theory and research. He was a teacher at the engineering school École nationale supérieure des mines de Paris. He is now best known for his insistence on the agency of nonhuman actors, and for introducing the concept of networks.
Emmanuel Mounier (1905–1950) was a guiding voice in the French personalist movement He was the founder and director of Esprit, the literary magazine that was the organ of the movement. Mounier, who was the child of peasants, was a brilliant scholar at the Sorbonne. In 1929, when he was only twenty-four, he encountered the French writer Charles Péguy, who inspired in him the ideas for the personalist movement.
Gabriel Honoré Marcel (1889–1973) was a leading Catholic existentialist and the author of about 30 plays. He was influenced by Bergson in his reception of the concept of 'being' as process, and he emphasized the idea that "being" remains mysterious to us.
Jean-Paul Sartre (1905–1980) probably still is the most famous french philosopher. He was also a dramatist, screenwriter, novelist and critic. He popularized (and named) existentialism, making it better known to the lay-person than, for instance, deconstruction. He was also a Marxist and a part of the phenomenological tradition.
Merleau-Ponty
Maurice Merleau Ponty (1908–1961) was a French phenomenologist philosopher, strongly influenced by Edmund Husserl. Merleau-Ponty was very close to Sartre and Simone de Beauvoir. He promoted a distinctly Heideggerian conception of Being.
It is important to note that many French Philosopher considered themselves as Marxists in one way or another. Also, most of them changed their views substantially during their lifetime. Sartre, for instance, became more influenced by Marx during the course of his life.
Alexandre Kojève (1902–1968) was a Marxist and Hegelian political philosopher, who had a substantial influence on intellectual life in France in the 1930s and on the reading of Hegel in France.
Louis Althusser (1918–1990) was a key Marxist philosopher. He read Marx through the lens of structuralism. Althusser's first seminal work was Reading Capital (1965), co-written with Étienne Balibar, Roger Establet, Jacques Rancière and Pierre Macherey. He opposed Hegel's teleological approach to history, drew on Bachelard's concept of "epistemological break" and defined philosophy as a "class struggle in theory."
Other Marxist authors include Henri Lefebvre (1901–1999), who partly influenced the Situationist movement, as well as Guy Debord, the group Socialisme ou Barbarie, etc.
The structuralist movement in French philosophy was highly influenced by the Swiss thinker Ferdinand de Saussure (1857–1913) and the linguist Roman Jacobson. Their ideas laid the foundation for many of the significant developments in linguistics in the 20th century.
Structuralism proposes that human culture can be theorized by means of a structure modeled on language (structural linguistics). This approach differs from positivism (direct access to concrete reality) and from the abstractions of idealism, and instead offers a "third order" that mediates between the two.
Claude Lévi-Strauss was an anthropologist who used the ideas of structuralism in order to create a structural theory of social and kinship relations.
Jacques Lacan (1901–1981) was a psychoanalyst who expanded Freudian psychoanalysis into a broader theory of the subject by combining it with linguistics, structuralism, and topology. He also contributed substantially to a theory of discourse. Similar to Althusser who developed a structural reading of Marxism, Lacan "reconstructed" Freudian psychoanalysis from a structural perspective.
Post-structuralist authors present different critiques of structuralism. The common themes include the rejection of the self-sufficiency of structures (they are not real objects,) and an interrogation of the binary oppositions that constitute many structures. Post-structuralists argue that structuralist conceptions of reality are too rigid; they over-confidently assume that the definitions of signs and meaning are both valid and fixed. They also criticize that authors employing structuralist theories are somehow above and apart from the structures they are describing.
Structuralism and Post-structuralism are deeply intertwined movements, and relatively ambiguous terms. These movements have been expanded into many other disciplines, for instance English Literature, Cultural Studies, Media Studies/Film Studies, Anthropology, etc.
Michel Foucault (1926–1984), starts with structuralism, but quickly developed his own brand of social analysis from a historical perspective. He called his approach to semiology and history "archeology." His influence is wide-ranging, and his work includes books such as Madness and Civilization (1961), The Order of Things (1966), Discipline and Punish: The Birth of Prison (1975) or The History of Sexuality.
Another post-structuralist thinker is Gilles Deleuze. He wrote the Anti-Oedipus (1972) with Félix Guattari, which criticizes psychoanalysis. They were, like Foucault, thinkers who introduced a thorough reading of Nietzsche in France. They build on Georges Bataille's (1897-1962) earlier work: Bataille published the Acéphale Review from 1936 to 1939, along with Pierre Klossowski, another close reader of Nietzsche, Roger Caillois and Jean Wahl. Deleuze wrote books such as Difference and Repetition, The Logic of Sense, Spinoza: Practical Philosophy (1970), and also wrote on Bergson, Leibniz, Nietzsche, etc., as well as other works on cinema (Cinema 1: The Movement Image). Both Deleuze and Foucault attempted to distance themselves from the strong influence of Marxism and psychoanalysis by means of a radical reinterpretation of Marx and Freud.
Jacques Derrida (1930–2004) was an Algerian-born French philosopher, known as the founder of deconstruction. His voluminous work had a profound impact upon continental philosophy and literary theory.
Jean-François Lyotard (1924–1998) was a philosopher and literary theorist. He is well known for his development of Postmodern theory after the late 1970s.
Other authors include:
Jean Baudrillard, who started with a situationist criticism of Consumption Society in the 1970s. His major themes reflect on simulation and virtual reality.
Paul Virilio, a philosopher and an urbanist who writes about technology, speed, and power.
Cornelius Castoriadis, who was, along with Claude Lefort, co-founder of Socialisme ou Barbarie and a critic of orthodox Marxism,
François Laruelle, who developed "Non-philosophy" starting in the 1980s,
Paul Ricoeur (administrator of the University of Nanterre during May '68),
Emmanuel Levinas, Vincent Descombes, etc.
The Feminist movement in contemporary France (or at least that which falls into the 'Philosophy' genre) is characterised more by deconstructionism and Marxism than much of Anglo-American Feminism. Key thinkers include psychoanalytic and cultural theorist, Luce Irigaray (born 1930), and psychoanalyst and writer Julia Kristeva (born 1941). See also Simone de Beauvoir.