Medieval philosophy was very much a part of Christian philosophy and theology. Ratramnus (d. c. 868) defended Gottschalk of Orbais' (808 – 868) views on double predestination, a controversy throughout Francia in the 9th century.^[4]

Ratramnus also later supported Gottschalk in his conflict with archbishop Hincmar (806 – 882) of Rheims, advisor to Charles the Bald. Hincmar of Rheims altered a hymn, changing the words trina deitas (triune God) for summa deitas (supreme God).^[5][6] Gottschalk accused Hincmar of Sabellianism, and Hincmar accused Gottschalk of Arianism.^[7]

Ratramnus also wrote Against the Objections of the Greeks who Slandered the Roman Church, a response to the Photian schism (863–867) and defense of the filioque addition to the Niceno-Constantinopolitan Creed.^[8]

The Benedictine monk of Marmoutier Abbey and empiricist Gaunilo is well known for his work In Behalf of the Fool.^[a] Gaunilo objects to Saint Anselm of Canterbury's (1033 – 1109) ontological argument for the existence of God found in Anselm's Proslogion (c. 1078). Gaunilo contends as a reductio that the same argument proves the existence of "the most perfect island".^[9] Lanfranc (c. 1010 – 1089) and Saint Anselm were Benedictine monks at Bec Abbey.^[10]

Medieval philosophy was also concerned with the problem of universals inherited from antiquity. Roscellinus (c. 1050 – c. 1121) defended nominalism, stating universals are merely an emission of sound (flatus vocis).^[11][12] Among Roscellinus' supporters was Raimbert of Lille.^[13]

Roscellinus also stated the three persons of the Trinity were not one substance, arguing if they were then God the Father and the Holy Spirit would have become incarnate along with God the Son. This prompted Anselm's De Fide Trinitatis et de Incarnatione Verbi Contra Blasphemias Ruzelini (On Faith in the Trinity and on the Incarnation of the Word Against the Blasphemies of Roscelin).^[14][15]

In 1092/1093, a council convoked at Soissons by the archbishop of Reims condemned his interpretation and accused Roscellinus of tritheism.^[16][17] Roscellinus recanted his theological beliefs, but later returned to professing them.^[18]

Anselm of Laon (d. 1117) studied under Anselm at Bec and was a leading proponent of philosophical realism who helped to pioneer biblical hermeneutics.^[19] William of Champeaux (c. 1070 – 1121) studied under Roscellinus and Anselm of Laon, and was also a proponent of realism.^[20] William was a friend of mystic Bernard of Clairvaux (1090 – 1153).^[20]

Catalan Ramon Llull (c. 1232 – c. 1316) visited Paris in the 1280s and Llullism became popular. Llulism is a philosophical system known as 'the Art' which propounds a belief in the unity of Christianity influenced by neoplatonism.^[47]

While Llull was not himself an alchemist, a number of works on alchemy were attributed to him, as well as to Arnaldus de Villanova (c. 1240 – 1311). Influenced by Joachim of Fiore, Arnaldus claimed that in 1378 the world would end and the Antichrist would come (De adventu Antichristi, 1288). He was imprisonsed and the Sorbonne ordered his works to be burned. Both Llull and Villanova had some influence on alchemist John of Rupescissa (c. 1310 – c. 1368), known for aqua vitae.^[48][49]

The nominalist beliefs of British philosopher William of Ockham were banned in Paris in 1339.^[50][51] Despite this his views proved influential.

Jean Buridan

Jean Buridan (c. 1301 – c. 1360) was a nominalist most famous as the namesake for Buridan's ass. Buridan criticized Aristotle's physics and developed the theory of impetus, a precursor to inertia.^[52] Buridan was also considered one of the foremost logicians of the later Middle Ages. For 200 years after Buridan's discussions, little was said about syllogistic logic.^[34]

Nicole Oresme (1325 – 1382) studied with Buridan. Together they studied acceleration or "uniformly difform motion".^[53]

Oresme was a counselor of King Charles V.^[54] Oresme practiced astronomy, and his commentary on Aristotle's De Caelo (On the Heavens) anticipated Copernicus with arguments for the view that the Earth rotates.^[55][56] Oresme also criticized Aristotelian notions of space and time, considering time independent of motion, perhaps influenced by, or at least agreeing with, the views of prior scholars Peter John Olivi (1248 – 1298) and Gerardus Odonis (1285 – 1349).^[57][58]

Oresme also contributed to economics and followed Aristotle in arguing against usury,^[59] even though Oresme said inflation was worse.^[60] His opposition to usury was shared by Thomists like Giles of Lessines (c. 1230 – c. 1304), as well as Giles of Rome (c. 1243 – 1316) student Italian Gerard of Siena (c. 1295 – 1336),^[61] and Peter John Olivi and Gerardus Odonis; and his master Buridan.^{[62][63][64][65]} Buridan and Oresme supported a metallist theory of money.^[60]

Pierre d'Ailly

Pierre d'Ailly (1351 – 1420) was a nominalist who taught the Sentences of Peter Lombard. His pupils were Jean Gerson (1363 – 1429) and Nicholas of Clémanges (c 1360 – 1440). All three philosophers were embroiled in the Western Schism of 1378, which sent many French taught scholars elsewhere. Gerson developed natural rights theory. Gerson also defended the divine mission of Joan of Arc.^[67]

University of Toulouse professor and physician Raymond Sebond (1385 – 1436) opposed the Ockhamists and was influenced by Llull. He attempted to reconcile reason and faith. Raymond declares that the Book of Nature and the Bible are both divine revelations.^[68] Sebond wrote the posthumously published Liber naturae sive creaturarum, originally written in Spanish, or Theologia naturalis seu liber creaturarum (1484).

Italian Renaissance humanist Gregory of Tifernas was the first teacher of Greek in France at the University of Paris in 1458.^[69] Guillaume Fichet (1433 – c. 1480) and Robert Gaguin (1434 – 1501) are usually looked upon as the first French humanists. Guillaume Budé (1467 – 1540) was another French humanist.

French Renaissance humanist Rabelais (c. 1490 – 1553) contributed to French philosophy in Gargantua and Pantagruel a belief in man uncorrupted by institutions, and ridiculed Pyrrhonism in the third book (1546).^[70]

Logician and education reformer Petrus Ramus (1515 – 1572) criticized Aristotle, writing Quaecumque ab Aristotele dicta essent, commentitia esse (Everything that Aristotle has said is false) (1536). The Ramists distrusted human thought and put faith in intuitive logical relations.^[71] The Dialogues (1557) of Ramist Guy De Bruès (b. c. 1530) were influential for entertaining skepticism.^[72][73]

The first writings on Ramism after the death of Ramus included biographies, and were by disciples of sorts: Freigius (1574 or 1575),^[74] Banosius (1576),^[75] and Nancelius [fr] (1599).^[b] Ramism had a lasting influence in Europe and even New England.

France also saw a Protestant movement following the Reformation, such as the Huguenots, which included precursors in such philosophers as Llullist Jacques Lefèvre d'Étaples (c. 1455 – c. 1536).^[77] Jean Bodin (c. 1530 – 1596) was critical of papal authority, preferring the sovereignty of an absolute monarch.^[78]

Ramus was a Protestant convert and a victim of the St. Bartholomew's Day massacre in 1572. Budé's family fled from France.

Henri Estienne (1531 – 1598) was responsible for the first printed Latin translation of the works of Pyrrhonian skeptic Sextus Empiricus in 1562.^[79]

Montaigne

Michel Eyquem de Montaigne (1533–1592) was famous for skepticism, summed up in his personal motto of Que sais-je? ("what do I know?") His highly influential writing style consists of essays (he coined the term) filled with autobiographical and casual anecdotes. Montaigne's best known skeptical essay is the circuitous Apology for Raymond Sebond, which recapitulates much from Sextus Empiricus.^[80]

Montaigne was also friends with political philosopher Étienne de La Boétie (1530–1563), author of the posthumously published Discourse on Voluntary Servitude (1577).

Modern philosophy began in France with René Descartes (1596–1650), who raised problems central to 17th century thought. An expat who lived in the Dutch Republic, he studied at the Jesuit school La Flèche and was a pioneer of mathematics and the Scientific Revolution.^[84] He founded a mechanistic philosophy which incorporated his own Cartesian physics. His philosophy was also rationalist and dualist and is known as Cartesianism, supported in works like Meditations on First Philosophy (1641) and Discourse on Method (1637). The three great rationalists of early modern philosophy are Descartes, Baruch Spinoza, and German philosopher Gottfried Wilhelm Leibniz (1646 – 1716).

It is often said Descartes changed the primary object of philosophical thought from ontology to epistemology.^[85] Descartes was concerned with the recent spread of skepticism by thinkers such as Montaigne, and desired to find indubitable ground on which all the sciences could be placed and progressively built. Thus he doubted anything he could and accepted only certain (or apodeictic) knowledge as truth.

After invoking the possibility of dreaming to doubt the information given to him from his senses and the external world, and further of an omnipotent deceiver to reject the information given to him from mathematics and logic, Descartes discovered at least one thing could be known for certain. Even if he doubted everything, if he himself was doubting, then he had to exist. Thus Cogito Ergo Sum—I think, therefore I am. This became his first principle.^[86][87]

Descartes then claimed that because he discovered the Cogito through perceiving it "clearly and distinctly", anything he can similarly perceive as clearly and distinctly must be true. Then he argues that he can conceive of an infinite being, but finite beings cannot produce infinite ideas and hence an infinite being must have put the idea into his mind. He uses this argument, commonly known as an ontological argument, to invoke the existence of a benevolent God as the indubitable foundation that makes all sciences possible.

Many people admired Descartes intentions, but were unsatisfied with this solution. Some accused him of circularity, proclaiming his ontological argument uses his definition of truth as a premise, while his proof of his definition of truth uses his ontological argument as a premise.

Another famous problem arises from Descartes’ substance dualism, first pointed out by Princess Elizabeth of Bohemia. For Descartes, a substance is that which can be conceived independently of everything else and exist independently of anything else. Since Descartes conceived of the mind independent of everything else when doubting everything uncertain, and because if he wanted to God could produce a world in which only the mind existed, he came to define the mind as a different substance from that of body. For Descartes, the mind is defined as an unextended substance and the body as an extended substance.^[88] This raised the fundamental question of how it is possible that mind and body interact with one another.^[89] Descartes also held as a result of his dualism that animals were mere machines.

Cartesianism attracted several followers such as Jansenist solitaires Antoine Arnauld and Pierre Nicole. Together they produced the Port-Royal Logic (1662), the "most influential logic book after Aristotle and before the end of the nineteenth century".^[90] In 1649, Nicolas Cornet sought the condemnation of five propositions from Cornelius Jansen's Augustinus. Arnauld defended the Jansenists.^[91]

Other Cartesians include Louis de La Forge (1632 – 1666), Géraud de Cordemoy (1626 – 1684), Claude Clerselier (1614 – 1684), University of Paris professor Edmond Pourchot (1651 – 1734), recollect Antoine Le Grand (1629 – 1699), physicist Jacques Rohault (1618 – 1672), mystic Pierre Poiret (1646 – 1719), Pierre-Sylvain Régis (1632 – 1707), and François Poullain de la Barre (1647 – 1723).

De la Barre influenced Gabrielle Suchon (1632 – 1703), who is the first to produce a significant body of work dedicated solely to the topic of women.^[92] Claude Buffier (1661 – 1773) supported women's education.

The Minim and polymath Marin Mersenne (1588 – 1648) wrote La Vérité des sciences (The Truth of Science) (1625), a dialogue between an alchemist, a skeptic and a Christian philosopher, the latter opposing both the over-confidence of the first and the excessive doubts of the second. The rest of the book is an 800 page compilation of mathematics to prove there is knowledge immune from doubt.^[93]

Mersenne was "the center of the world of science and mathematics during the first half of the 1600s"^[94] and, because of his ability to make connections between people and ideas, "the post-box of Europe".^[95] As well as France, Mersenne corresponded with scholars in the Dutch Republic, England, and Italy, including Constantijn Huygens, Thomas Hobbes, and Galileo Galilei.

Blaise Pascal (1623 – 1662) was a Cartesian and a child prodigy mathematician and scientist who grew increasingly religious.^[96] Pascal was a vacuuist who repeated the barometric mercury experiments of Evangelista Torricelli,^[97] while Descartes was a plenist who held "nature abhors a vacuum".

Pascal is known for defending Jansenism and Arnauld in Provincial Letters (c. 1657).^[98] Pascal was also a fideist. His aphoristic collection Pensées (1670) is a name given posthumously to fragments that Pascal had been preparing of an apology for Christianity, which was never completed. Pensées contains Pascal's Wager.^[c] Pascal's Wager is an early application of the mathematics of probability, and says people engage in a life-defining gamble regarding the belief in the existence of God.

Cartesian Nicolas Malebranche (1638–1715) believed not even substances of the same kind could interact with each other, because no necessary causation could be perceived. He proposes then that it is God, an uncreated substance, who brings it about that each time one perceives a 'cause', one also perceives an 'effect'. Hence the doctrine is named occasionalism.^[100] This doctrine saw predecessors in Louis de La Forge, Géraud de Cordemoy, and the Flemish Arnold Geulincx.

Malebranche was well-known and celebrated in his own time, but has since become somewhat of an obscure figure. However, his philosophy had a direct influence upon Spinoza and Scottish skeptic David Hume.

The most influential anti-Cartesian in France was Pierre Gassendi (1592 – 1655), who sought to revive Epicureanism. Gassendi was also a nominalist. Historian of philosophy Richard Popkin indicates that Gassendi was one of the first thinkers to formulate the modern "scientific outlook".^[101] Gassendi famously tracked the transit of Mercury in 1631.^[102] Another influential critic of Descartes was churchman Pierre Daniel Huet (1630 – 1721).^[103][d]

Pierre Bayle (1647 – 1706) was a Huguenot who fled to Rotterdam in the Netherlands and wrote a biographical dictionary the Historical and Critical Dictionary (1697). His views were dubbed "super skepticism" by Popkin. Bayle would characterize his own views differently, stating "I know too much to be a Pyrrhonist, and I know too little to be a Dogmatist".^[105]

Bayle's discussion of the problem of evil inspired Leibniz, who wrote in Latin and French, to publish his Théodicée (1710).^[106] Leibniz was an optimist who believed God made the best of all possible worlds. Bayle was also an influence on David Hume.^[107]

Charles de Secondat, baron de Montesquieu (1689–1755) was a social commentator and political philosopher. His theories deeply influenced the American Founders. His belief that the state powers be separated into legislative, executive, and judicial branches formed the basis for separation of powers under the United States Constitution. In The Spirit of the Laws (1748), Montesquieu outlined the view that man and societies are influenced by climate. He believed that hotter climates create hot-tempered people and colder climates aloof people, whereas the mild climate of France is ideal for political systems.^[e]

François-Marie Arouet, better known as Voltaire (1694–1778), came to embody the Enlightenment with his criticisms of Church dogma and French institutions, his defense of civil liberties and his support of social reform. He fought for the right to a free trial and freedom of religion. Voltaire was a deist, and was twice sentenced to prison, and once to temporary exile to England.

A heavy influence on the Enlightenment was the work of British natural philosopher Sir Isaac Newton and the philosophy of Newtonianism, who published his Philosophiæ Naturalis Principia Mathematica (1686), which included his laws of motion, introducing classical mechanics in physics.^[108]

Voltaire and Émilie du Châtelet (1706 – 1749) wrote Elements of the Philosophy of Newton (1738), helping to popularize Newtonianism in France alongside Pierre Louis Maupertuis.^[109] Châteltet was the first woman published by the French Academy of Sciences. Voltaire's Letters on the English (1734) introduced French readers to the philosophy of the British empiricists like Newton and John Locke, as well as to playwright William Shakespeare.^[110]

Voltaire is best remembered today for his aphorisms and his satire of Leibniz known as Candide (1759), written soon after the 1755 Lisbon Earthquake,^[111] which tells the tale of a young believer in Leibnizian optimism who becomes disillusioned after a series of hardships.

Voltaire's anonymously published Philosophical Dictionary (1764) was censored in many countries, including Switzerland (Geneva) and France, where all available copies of the book were collected and burned in the town square.^[112][113]

Jean-Jacques Rousseau (1712–1778) distinguished himself from the progressive scientism of the Enlightenment with his proclamation in Discourse on the Arts and Sciences (1750) that art and science are corruptors of human morality. Furthermore, he caused controversy with his theory that man is good by nature but corrupted by society, in contradiction to the Christian doctrine of original sin.

Rousseau's The Social Contract (1762) advances social contract theory and states that only the general will of the people has the right to legislate. It famously begins “Man is born free, and everywhere he is in chains.” Upon publication, the distribution of The Social Contract in France was prohibited, and Rousseau fled the country to avoid imprisonment.^[114]

However it influenced the French Revolution. Rousseau was so highly praised by the French revolutionists that in 1794 his remains were moved to the Panthéon in Paris. Rousseau's Emile (1762) had previously been forbidden and publicly burned, but became the basis of a new national system of education.^[115] His picture was the only one to grace the home of German philosopher Immanuel Kant.

Some of his theories continue to be controversial, such as his idea of the general will, which has been accused of both fascism and socialism. His critique of private property in works like Discourse on Inequality (1755) has been seen as a forebear to Marxist ideology.

Étienne-Gabriel Morelly (1717–1778) was mistaken for Rousseau. Gabriel Bonnot de Mably (1709–1785) was influenced by Rousseau. Both influence socialism.^[116] Victor d'Hupay (1746–1818) coined the term communism.

Benjamin Constant (1767–1830) was a critic of Rousseau. Constant was a liberal and a collaborator with Madame de Staël (1766–1817).

Denis Diderot (1713–1784) was a key collaborator in the creation of the Encyclopédia, with mathematician Jean le Rond d’Alembert (1717–1783) and publisher André Le Breton (1708–1779). A systematic collection of all the information of the arts and sciences, the Encyclopédia caused great controversy. Diderot was harassed repeatedly by the police, and was even arrested.^[117] The ecclesiastical party disliked the Encyclopédia, which was a threat to the aristocracy because it asserted that the state should take care of the people and not itself, religious freedom, freedom of thought and the value of science and industry.^[118] In the end, Le Breton began removing all articles he deemed controversial in fear of punishment. The Encyclopédia that Diderot had worked on for twenty years was ruined beyond repair.^[119]

D'Alembert was the teacher of Marquis de Condorcet (1743–1794) who supported free markets and equality, including for women. His wife was Sophie de Condorcet, who also ran a salon.

Influenced by Locke and Voltaire, Catholic priest Étienne Bonnot de Condillac (1714–1780) founded the philosophy of sensationalism.^[120] Idéologues Antoine Destutt de Tracy (1754–1836), physiologist Pierre Jean Georges Cabanis (1757–1808), and Pierre Laromiguière (1756–1837) were followers of Condillac.

Julien Offray de La Mettrie (1709 – 1751) was a physician and materialist, best known for his L'homme machine (Man a Machine, 1747). La Mettre took Descartes' doctrine that animals are machines and also applied it to people, arguing against immortal souls. He had to flee France and settle in Berlin.^[121]

Claude Adrien Helvétius (1715 – 1771) was also a materialist, and argued against Montesquieu's climate theory. Helvétius published the sensationalist De l'esprit (On Mind) (1758), which said that the only real motive is self-interest, therefore there is no good and evil, only competitive pleasures. Its non-religious, utilitarian and egalitarian doctrines raised a public outcry, and the Sorbonne publicly burned it in 1759, forcing Helvétius to issue several retractions.^[122]

Baron d'Holbach (1723–1789) was a materialist who promoted atheism and ran a salon, which helped in the dissemination of "Protestant and especially German thought".^[123] He wrote The System of Nature (1770) and The Universal Morality (1776). Jacques-André Naigeon (1738–1810) was another atheist.

The sensationalists were opposed by Christian traditionalists like Louis de Bonald (1754–1840) who believed in revelation, and Félicité de La Mennais (1782–1854) who was a skeptic.^[124]

The deism and atheism was combated by Pascal-influenced Catholics like Jacques-Bénigne Bossuet (1627 – 1704), a student of Cornet, and Nicolas-Sylvestre Bergier (1718 – 1790), who influenced Counter-Enlightenment and conservative figure Joseph de Maistre (1753 – 1821), who influenced Ultramontanism.^[125][126] Bossuet supported the king's revocation of the Edict of Nantes (Edict of Fontainebleau, 1685), which abolished the rights of the Protestant minority.^[127]

The French Revolution began in 1789. Maximilien Robespierre (1758–1794)and Jean-Paul Marat (1743–1793) were radical Jacobin leaders and Montagnards who supported the sans-culottes. Both Robespierre and Marat were elected as deputies to the National Convention. Robespierre was appointed a member of the Committee of Public Safety and Marat a member of the Committee of General Security; both formed the provisional government during the Reign of Terror (c. 1793-1794).^[128]

Despite Catholic Red Priests like Jacques Roux, an elected member of the Paris Commune, the French Revolution was opposed to the Church. During the Terror, before the Revolutionary Tribunal could try Jacques Roux, he committed suicide.

Revolutionaries like Antoine-François Momoro (1756–1794) supported the atheistic Cult of Reason, and Robespierre started the deistic Cult of the Supreme Being.^[129] The National Convention decreed that a rotating series of holidays would occur every décadi, the equivalent to a week in the new French Republican Calendar. Robespierre declared that 20 Prairial Year II (8 June 1794, also the Christian holiday of Pentecost) would be the first day of national celebration of the Festival of the Supreme Being.

Marat was assassinated in his bathtub by reactionary Charlotte Corday, who was herself soon executed by the guillotine on the Place de Grève. Condorcet died in prison after a period of hiding from the authorities. Members of the Convention turned against Robespierre, and he was arrested without trial and executed by guillotine on the Place de la Révolution. There was then the Thermidorian Reaction and the First White Terror.

The Conspiracy of the Equals was led by François-Noël Babeuf, who was influenced by Abbe de Mably.^[130] The group published The Manifesto of the Equals (1796).

The philosophy of French revolutionary Henri de Saint-Simon (1760–1825) birthed Saint-Simonianism which believed in science's ability to transform society, in works such as his Introduction to scientific discoveries of the 19th century (1803) and his Notes on the study of man (1813), the latter of which is a eulogy to Napoleon,^[131][f] who ended the Revolution with the Coup of 18 Brumaire (9 November 1799), establishing himself as head of the Consulate and eventually Emperor of the French. Saint-Simon was also a Christian writing Le Nouveau Christianisme (The New Christianity) (1825).^[132]

Saint-Simon's intellectual rival was mathematician and physicist Pierre-Simon Laplace (1749–1827). Known as the "French Newton", he argued for determinism with Laplace's demon.^[133]

Pierre Paul Royer-Collard (1763–1845) was leader of the Doctrinaires group during the Bourbon Restoration (1814–1830). He brought Scottish common sense realism to France,^[134] shown in his pupil Victor Cousin (1792–1867).

Cousin had also learned under Laromiguière at École Normale Supérieure, and was influenced by Kant and German idealism as well. Cousin is the founder of eclecticism.^[124]

A student of Cousin was Théodore Jouffroy (1796–1842), also influenced by Scottish philosophy. Adolphe Garnier (1801–1864) continued Jouffroy's work. Garnier's Treatise on the Faculties of the Soul (1852) won the Montyon Prize.^[135]

French spiritualism was influenced by Maine de Biran (1766–1824), at first a follower of Condillac, but who became a mystical theosophist influenced by Pascal.^[136] Maine de Biran's diary covers the melancholy and tension of the Hundred Days, Napoleon's exile and return culminating in his final defeat at the Battle of Waterloo (1815), and permanent exile.^[137]

Félix Ravaisson-Mollien (1813–1900) and Jules Lachelier (1832–1918) were also influenced by German idealism, but distinguished their views from Cousin's, preferring spiritualism.^[138]

Lachelier taught Jules Lagneau [fr] (1851–1894) and Émile Boutroux (1845–1921), a critic of materialism in science. Alfred Jules Émile Fouillée (1838–1912) was a spiritualist who believed in "idea-forces". Fouillée influenced Jean-Marie Guyau (1854–1888).

An idiosyncratic French philosopher likely influenced by Maine de Biran was Jules Lequier (1814–1862).^[136]

Saint-Simon influenced the utopian socialism of Charles Fourier (1772–1837) and Fourierism. Fourier influenced Christian and utopian socialist Étienne Cabet (1788 – 1856), who was a more radical revolutionary than Fourier.^[139][140] Cabet saw Christianity as synonymous with socialism.^[141]

Christian and socialist Louis Blanc (1811 – 1882), a historian of the July Revolution of 1830 who opposed the July Monarchy, was a member of the provisional government during the Revolution of 1848.^[142] Blanc was exiled but returned to France in time for the defeat in the Franco-Prussian War (1870). He did not support the revolutionary Paris Commune, but he successfully proposed amnesty for the Communards.

Saint-Simon and the book by Philippe Buonarroti (1761 – 1837) History of Babeuf’s Conspiracy of Equals (1828) influenced socialist philosopher Louis-Auguste Blanqui (1805–1881), the founder of Blanquism.^[143] Blanquism believes that socialist revolution should involve a coup d'etat by a relatively small group of highly organised and secretive conspirators.^[144] Blanqui participated in the July Revolution of 1830, and was a leading voice in the radical clubs of the Revolution of 1848. Blanqui spent 33 of his life in prison, earning him the nickname L'Enfermé ("The Prisoner").

Fourier was an influence on anarchist Pierre Joseph Proudhon (1809–1865).^[145] Proudhonism supports mutualism, a kind of market socialism. Proudhon published The Philosophy of Poverty (1846), prompting a book-length critique from Karl Marx entitled The Poverty of Philosophy (1847), starting a rift which resulted in the split between anarchism and Marxism at the First International (1864). It continued with the followers of Russian collectivist anarchist Mikhail Bakunin and lasts to this day.^[146]

After the suppression of the Revolutions of 1848, radicalism and republicanism declined. Louis Blanc, Romantic author Victor Hugo (1802–1885), and historian Edgar Quinet (1803–1875) attended the first meeting of the League of Peace and Freedom.^[147] One-time president of the League Émile Arnaud coined the term pacifism.^[148]

Auguste Comte (1798–1857) was the founder of sociology and the philosophy of positivism, and may be regarded as the first modern philosopher of science.^[149]

Influenced by Fourier and Saint-Simon, Comte developed the positive philosophy to remedy the aftermath of the French Revolution, calling for a new social paradigm based on the sciences. Comte offered an account of social evolution, proposing that society undergoes three phases in its quest for the truth according to a general 'law of three stages'. Comte's stages were (1) the theological, (2) the metaphysical, and (3) the positive.^[150]

While originally a follower of Saint-Simon, Comte traced his own path since he was not a Christian.^[132] He attempted to introduce a cohesive "religion of humanity" which, though largely unsuccessful, was influential for various Secular Humanist organizations in the 19th century. Comte also coined the term "altruism".^[151]

Comte's student Charles Renouvier (1815–1903) was influenced by Lequier and was a German idealist. Sociology pioneer Émile Durkheim (1858–1917) read Comte and Renouvier.^[152] Durkheim was a structural functionalist, and one of his best known works is Suicide (1897).

Cousin and Comte influenced Hippolyte Taine (1828–1893), the founder of French literary naturalism, and a proponent of sociological positivism and historicism. Deeply shaken by the defeat of 1870, as well as by the insurrection (and violent repression) of the Paris Commune, Taine became devoted to his major historical work, The Origins of Contemporary France (1875–1893).

Comte was also of considerable influence outside of France, impacting the work of thinkers such as Karl Marx and John Stuart Mill.^[153]

Ferdinand de Saussure (1857–1913) was a Swiss linguist who taught for many years in Paris. He was concerned with distinguishing linguistics from philology by moving from the study of the history of individual words and comparisons of languages to the study of the essential underlying structures of language. His small output of work, such as the Course in General Linguistics (1916), most of which was published posthumously, became the foundations of linguistics, semiotics and structuralism, the school of philosophy concerned with the underlying structures which form, limit and affect society, language and the human mind.

Saussure divided language into two parts: the langue, which is the system of signs and rules owned by a community, and parole, the individual acts of speech within the given community. This was likened by Saussure to chess and a game of chess, for before anyone can play, they have to know the rules and structure of the game.^[154]

For Saussure, the essential unit of any language is the word, or sign. Like language, he divides the word into two inseparable parts: the signifier, which is the sound image, and the signified, which is the concept associated with the signifier. Saussure stressed the arbitrariness of this association, maintaining that any signifier can refer to any signified. How a sign obtains its meaning is by what it is not within the langue, not what it is. For example, the word ‘dog’ means dog simply because it does not mean cat, bird or cornflakes.

For Saussure, language can be studied synchronically, i.e. as a complete system within a frozen moment of time, or it can be studied diachronically, which is the examination of its historical development. It can be said that structuralists focused on the synchronic aspects of culture, while poststructuralists, as a reaction toward the highly dualistic and deterministic characteristics, focussed on the diachronic aspects of culture in an attempt to invoke a grey area.^[155]

While Ferdinand de Saussure was a relatively obscure thinker in his time, it may be said that Henri Bergson (1859–1941) was somewhat of a celebrity. His philosophy appealed both to academics and the general public. Bergson was awarded the Nobel Prize for Literature in 1927 "in recognition of his rich and vitalizing ideas and the brilliant skill with which they have been presented".^[156] Although Bergson was a major influence on early 20th century thought, interest in his work greatly decreased after World War II. In the late 20th century came a revitalization of interest in Bergson’s oeuvre, through the works of self-proclaimed Bergsonian Gilles Deleuze.^[157]

All of Bergson’s works were concerned with his theory of real time as it is experienced by consciousness. He coined the term élan vital, establishing vitalism in works like Creation Evolution (1907), and was the French representative of Lebensphilosophie.

Bergson believed substance pluralism and substance monism are in fact just two representations of the same phenomenon. He sought to improve on Lachelier,^[158] and the evolutionary philosophy of Herbert Spencer, and has likened consciousness to the rolling and unrolling of thread, to represent man’s sense of mortality and the continual gain of new memory. However, these images are insufficient and can only show the idea indirectly. Bergson maintains that the case is the same for any other image of the idea one can produce.^[159]

Bergson calls this idea Duration and defines it as being qualitative, not quantitative, unextended, not extended, a multiplicity yet a unity, mobile and continuously interpenetrating itself. However, it should be warned that Bergson believes Duration cannot be represented by concepts either. Bergson calls the creation of concepts analysis and believes it can never represent the absolute. He likens it to constructing a model of a city out of a collection of photographs taken from every angle and a poem being translated and having commentary piled upon commentary: the model of the city can never replicate the feeling of being in the city itself and the translation and commentaries can never give the simple dimensional value of walking in the city itself. Indeed, symbols always distort the part of an object they represent through generalization to include it and every other objects’ part they represent.^[159] The Duration can only be grasped through intuition. Intuition is a complete philosophical method that involves placing oneself within the Duration.^[159]

Writers outside of French philosophy influenced by Bergson include the novelist Marcel Proust, American philosopher William James, and British philosopher Alfred North Whitehead.

Henri Poincaré

Pierre Duhem

Philosophy of science is a branch of philosophy concerned with the foundations, methods,^[160] and implications of science. The central questions of this study concern what qualifies as science, the reliability of scientific theories, and the ultimate purpose of science. In France, philosophy of science, also known as French historical epistemology^[161][162] or French epistemology,^[163] was a prominent school of thought with Henri Poincaré, Émile Meyerson, Pierre Duhem, Léon Brunschvicg, Gaston Bachelard, Alexandre Koyré, Jean Cavaillès, Georges Canguilhem, Jean-Toussaint Desanti, Jules Vuillemin, Gilbert Simondon, Michel Serres, and Jean-Michel Berthelot.

Henri Poincaré (1854–1912) had views on the philosophy of mathematics opposite to those of analytic philosophers Bertrand Russell and Gottlob Frege, who believed that mathematics was a branch of logic.^[g] Poincaré strongly disagreed, claiming that intuition was the life of mathematics. Poincaré's view is known as pre-intuitionism or conventionalism, a view he also carried into the philosophy of science. His views are found in the book Science and Hypothesis (1902).^[164]

Thermodynamicist Pierre Duhem (1861–1916) introduced the Duhem thesis in works such as The Aim and Structure of Physical Theory (1906), an early form of confirmation holism, which says a single scientific hypothesis can never be falsified by itself, coming with a combination of other theories.^[h] Duhem also sought to revise the history of science from its anti-Catholicism and founded the history of medieval science with the ten volume Le système du monde: histoire des doctrines cosmologiques de Platon à Copernic (The System of World: A History of Cosmological Doctrines from Plato to Copernicus), beginning in 1913.^[42][165]

Gaston Bachelard (1884–1962) introduced the concepts of epistemological obstacle and epistemological break (obstacle épistémologique and rupture épistémologique). Jean Cavaillès (1903–1944) specialized in philosophy of science concerned with the axiomatic method, formalism, set theory and mathematical logic. Jules Vuillemin (1920–2001) introduced the concept of the philosophy of algebra and was specialized in philosophy of knowledge. Vuillemin introduced analytic philosophy to France.^[166] Georges Canguilhem (1904–1995) reintroduced vitalism into the philosophy of biology.

Alain (1868–1951) was taught by Lagneau, and himself taught Simone Weil and Georges Canguilhem. Alain supported the Radical Party.

Simone Weil (1909–1943) was a French philosopher, mystic and political activist who greatly influenced 20th century philosophy including influencing Pope Paul VI. Her notable ideas include decreation (renouncing the gift of free will as a form of acceptance of everything that is independent of one's particular desires; making "something created pass into the uncreated"), uprootedness (déracinement), obligations as the basis of rights, attention as compassion, patriotism of compassion, abolition of political parties, the unjust character of affliction (malheur), and that compassion must act in the area of metaxy.^[169]

The revolutionary syndicalist, and friend of anarchist Fernand Pelloutier, Georges Sorel (1847–1922) founded Sorelianism. Sorel was an advocate of violence and a believer in the power of myth, who wrote Reflections on Violence (1908). He was influenced by Proudhon and Bergson's Lebensphilosophie.^[170]

Phenomenology can be defined as a way of philosophizing which involves descriptive explanations of phenomena as it is given to consciousness and how it is given to consciousness, which attempts to avoid imposed explanations. In France, phenomenology was influenced by Lebensphilosophie and seen as a radical Cartesianism which rejected substance dualism to better understand consciousness. Phenomenology is still an important area of research in France today.^[171] It also influenced existentialism and many postmodern philosophers' thought.^[i]

Emmanuel Lévinas (1906–1995) was one of the first to introduce phenomenology to France, through his translation of Husserl’s Cartesian Meditations. Lévinas considered ethics primary in philosophy and once proclaimed that it precedes metaphysics and should be considered the first philosophy. He developed a moral philosophy based around notions of the other and the face which introduced ethics into phenomenology, which had been missing since the demise of Max Scheler.^[171]

Maurice Merleau-Ponty (1908–1961) was concerned with the foundations of perception. His theory of the subject-body was produced as an alternative to Descartes' Cogito and substance dualism. In contrast to the clear distinction between the mind and the external world, where the latter is but an extension of the former, the subject-body is an existential account of the pre-reflective subject, the subject's perception and the world as intricately intertwined.

Paul Ricœur (1913–2005) was one of the first to introduce phenomenology to France. He was best known for combining phenomenological description with hermeneutics. He was awarded the Kyoto prize in arts and philosophy for having "revolutionized the methods of hermeneutic phenomenology, expanding the study of textual interpretation to include the broad yet concrete domains of mythology, biblical exegesis, psychoanalysis, theory of metaphor, and narrative theory.

Existentialism was a prominent school of thought in the first half of the 20th century. Traditionally, existentialism is concerned with the human condition, exploring such topics as purpose, freedom and the experience of the other. It can trace its roots back to philosophers such as Søren Kierkegaard, Friedrich Nietzsche and Martin Heidegger, as well as Lebensphilosophie, but bloomed with the thought of French phenomenologist Jean-Paul Sartre.

Camus

Albert Camus (1913–1960), winner of the 1957 Nobel Prize in Literature, rejected being labelled an existentialist, preferring to be called an absurdist.^[174] In the opening pages of The Myth of Sisyphus (1942), he states what he considers to be the fundamental question of philosophy: is suicide the correct response to an absurd world? Likening a Godless life to the story of Sisyphus, where he is doomed forever to push a rock up a hill only for it to roll down again, Camus’ answer is "No. It requires revolt. [...] The struggle itself is enough to fill a man’s heart. One must imagine Sisyphus happy."^[175] Camus also wrote The Stranger (1942), ranked greatest book of the 20th Century by Le Monde.^[176]

French Structuralism played a major role in intellectual thought after World War II. However, by the end of the century it was seen as important not by itself, but for the schools of thought it produced, such as poststructuralism and deconstruction. Structuralism finds its roots in the thought of Ferdinand de Saussure, who was concerned with linguistics. But soon structuralism began to be applied to anthropology, social sciences and psychology. It rejected existential concepts of freedom for the idea of man as determined by structures, following such thinkers as Claude Lévi-Strauss and Jacques Lacan.

Claude Lévi-Strauss (1908–2009) applied Saussure’s structuralism to anthropology, called structural anthropology, seeing culture as a system of symbolic communication.^[178]

Roland Barthes (1915–1980) was a literary critic and semiologist who applied Saussure’s thought to literary theory. In Mythologies, Barthes explored articles, advertisements, movies, etc. to demonstrate the deep-seated bourgeois propaganda found within. He described these myths as second-order signs. A certain form of green bottles signify red wine. The bourgeois then assign a second signifier to this signifier, that of relaxing, healthy, strong wine, be it to sell products or uphold the status quo.

Jacques Lacan (1901–1981) was a psychoanalyst who sought to explain the mind in terms of structures both in order to correct perceived errors in Freud’s thought as well as errors in the subsequent interpretation of Freud through the theories of Saussure, Strauss and Barthes. Lacan was also influenced by German philosophers Heidegger, Marx, and G. W. F. Hegel, through scholars Jean Hyppolite and Alexandre Kojève.

Louis Althusser (1918–1990) and his colleagues, prominently including Étienne Balibar, reworked Marxism using insights from structuralism, against the so-called "humanist" trend in Sartrean and Western Marxisms. Althusser offered an influential new reading of Marx's work, describing an "epistemological break" between the young, Hegelian Marx and the late Marx of Das Kapital. With his focus on the economic level and theory, Althusser came into conflict with social historians, such as E. P. Thompson.

The second half of the 20th century saw the rise of so-called postmodern thought. This rise was especially noticeable in France. However, the term is fairly hard to define. In fact, some people maintain that it is nothing but a slur applied to a group of disparate philosophers wrongly grouped together. However, it can also be seen as a critique of modernity and traditional western thought, particularly dichotomies and the belief in progress, influenced heavily by structuralism, phenomenology and existentialism.

Foucault

Michel Foucault (1926–1984) maintained a similar scepticism about absolutes, such as right and wrong, sane and insane, and human nature. His method was not to deny such notions, but to historicize them, examining what in the supposedly necessary may be contingent, and demonstrating the relationships between power, politics, and knowledge.

Foucault was anti-Hegelian and anti-teleological in his historical excavations. Foucault's four-volume The History of Sexuality introduced the concept of biopower. His works like The Order of Things (1966) saw a shift from "archaeological method" or episteme to "genealogical method" or dispositif.

His main fields of investigation were psychiatry, medicine, and institutions. Through his examinations of psychiatry in Madness and Civilization (1961), he showed that the development of psychiatry was not an obvious improvement on previous treatments of the insane, and that furthermore, the apparent scientific neutrality of psychiatric treatments hides the fact that they are a form of controlling defiance of bourgeois society.^[180] Foucault introduced the idea of a disciplinary institution in Discipline and Punish (1975).

Derrida

Jacques Derrida (1930–2004) believed Western philosophy had become phonocentric. Derrida in works like Of Grammatology (1967) developed deconstruction as a response to structuralism. Deconstruction takes a text, examines binary oppositions within it from several different interpreting standpoints, and then attempts to show them to be dependent upon one another, unstable, ambiguous and historically and culturally defined. This method is called différance.^[181] Through showing the fluidity of the dichotomies, deconstruction shows the fluidity of the text. Derrida maintained that no meaning is stable, not even the dichotomies classical philosophers took for granted. Through an internal logic, the text deconstructs itself and hence allows highly original interpretations.