Philosophers Who Changed the Structure of Philosophy

This list uses a stricter standard than fame, academic position or influence as a historian of philosophy. The question is whether a thinker posed a new fundamental problem, established a new conceptual structure, changed philosophy's subject matter or method, or redrew basic relations.

The field 'Principal inheritances and responses' records the most important intellectual sources or background questions. It does not imply that a thinker can be reduced to those predecessors. 'The genuinely new structure' asks what irreducible structure remains if the principal sources are set aside.

Dates for ancient figures are often disputed. Approximate dates and century ranges are marked as such; an open-ended date indicates a living philosopher.

1｜Thales｜c. 624–546 BCE｜Ancient Greece. Main structural contribution: He sought a single natural origin for the world without recourse to myth, making the origin of all things a philosophical question. Principal inheritances and responses: Ionian observation of nature and early cosmological myths The genuinely new structure: He shifted the starting point of explanation from divine genealogy to a debatable natural principle.

2｜Pythagoras｜c. 570–495 BCE｜Ancient Greece. Main structural contribution: He connected mathematical structure with cosmic order. Principal inheritances and responses: Early Greek cosmology, religion and mathematical practice The genuinely new structure: He made number and proportion basic structures of reality, beginning the tradition of understanding the world through formal relations.

3｜Confucius｜551–479 BCE｜China. Main structural contribution: He grounded human order in relationships, ritual, benevolence and self-cultivation. Principal inheritances and responses: Western Zhou ritual institutions and early traditions of rites and music The genuinely new structure: He internalised external ritual as personal cultivation and relational ethics, making ethical order a structure people could consciously practise.

4｜Heraclitus｜c. 540–480 BCE｜Ancient Greece. Main structural contribution: He brought change, opposition and Logos into ontology. Principal inheritances and responses: Ionian natural philosophy The genuinely new structure: He understood opposition and change as constitutive of order rather than its destruction, establishing a dynamic account of being.

5｜Parmenides｜c. 515–450 BCE｜Ancient Greece. Main structural contribution: He radically posed the question of being and distinguished being from non-being in logic. Principal inheritances and responses: Early natural philosophy and reflection on change The genuinely new structure: He first made being itself a rigorous object of reasoning, limiting philosophical inference by the unthinkability of non-being.

6｜Laozi｜Dates unknown, usually placed in the sixth to fifth centuries BCE｜China. Main structural contribution: He treated the Dao as a fundamental principle prior to particular beings and human order. Principal inheritances and responses: Early Chinese cosmology and criticism of ritual institutions The genuinely new structure: He explained the world through the generative relation of Dao, non-being and being, and redefined how order arises through reversal and non-action.

7｜The Buddha (Śākyamuni)｜Around the fifth century BCE; exact dates disputed｜Ancient India. Main structural contribution: He reinterpreted the subject and world through dependent origination, non-self, suffering and liberation. Principal inheritances and responses: Brahmanical tradition and śramaṇa movements The genuinely new structure: He replaced permanent substance and fixed self with conditioned relations, understanding existence as a process of dependent arising.

8｜Socrates｜c. 470–399 BCE｜Ancient Greece. Main structural contribution: He shifted philosophy towards human life, ethics and the definition of concepts. Principal inheritances and responses: Sophistic movement and public debate in Athens The genuinely new structure: He made the question of what a concept means a central philosophical method and placed self-examination at the heart of life.

9｜Mozi｜c. 470–391 BCE｜China. Main structural contribution: He proposed inclusive care, merit-based appointment and judgements based on benefit, while developing early forms of argument. Principal inheritances and responses: Confucian ritual and Warring States political realities The genuinely new structure: He replaced ethics based on degrees of kinship with standards of generalisable benefit and consequence, strengthening reasoned normative judgement.

10｜Democritus｜c. 460–370 BCE｜Ancient Greece. Main structural contribution: He explained the world through atoms and void. Principal inheritances and responses: Leucippus and early natural philosophy The genuinely new structure: He reduced complex change to indivisible entities and their movement and combination, establishing a characteristic reductionist ontology.

11｜Plato｜c. 428/427–348/347 BCE｜Ancient Greece. Main structural contribution: He developed the theory of Forms and systematically distinguished appearance from reality and sense from reason. Principal inheritances and responses: Socrates, Parmenides and Pythagoras The genuinely new structure: He made universal forms an independent level of reality and connected soul, knowledge, politics and being in a system.

12｜Aristotle｜384–322 BCE｜Ancient Greece. Main structural contribution: He developed formal logic, substance, four causes, and potentiality and actuality. Principal inheritances and responses: Plato and the pre-Socratics The genuinely new structure: He reconstructed being through substance, form, matter, causation and potentiality, organising philosophy into systematic fields.

13｜Zhuangzi｜c. 369–286 BCE｜China. Main structural contribution: He examined the limits of knowledge and language, subjective perspectives and value distinctions. Principal inheritances and responses: Laozi, the School of Names and Warring States debates The genuinely new structure: He made the dependence of judgement on perspective and the limits of language philosophical problems in their own right.

14｜Mencius｜c. 372–289 BCE｜China. Main structural contribution: He developed an account of innate goodness and moral psychology. Principal inheritances and responses: Confucius and the Confucian tradition The genuinely new structure: He grounded ethical norms in inner beginnings such as compassion, moving from institutional ethics towards the structure of the moral subject.

15｜Epicurus｜341–270 BCE｜Ancient Greece. Main structural contribution: He combined atomism, epistemology and ethics. Principal inheritances and responses: Democritean atomism and Cyrenaic ethics The genuinely new structure: He put natural philosophy to work in dispelling fear and achieving tranquillity, linking cosmology to a way of life.

16｜Zeno of Citium｜c. 334–262 BCE｜Ancient Greece. Main structural contribution: He founded early Stoicism. Principal inheritances and responses: Socratic traditions, Cynicism and Heraclitus The genuinely new structure: He connected cosmic determinism with inner freedom, forming an ethics of living in accordance with nature.

17｜Xunzi｜c. 310–235 BCE｜China. Main structural contribution: He proposed a theory of bad human nature, its transformation through deliberate activity, and the artificial construction of ritual. Principal inheritances and responses: Confucianism of Confucius and Mencius and ritual tradition The genuinely new structure: He explained civilisation and ethical order as achievements of human construction and education rather than spontaneous products of nature.

18｜Han Fei｜c. 280–233 BCE｜China. Main structural contribution: He explained political order through institutions, power and constraints on incentives. Principal inheritances and responses: Shang Yang, Shen Buhai, Shen Dao and Xunzi The genuinely new structure: He shifted the basis of political stability from the ruler's virtue to reproducible structures of law, technique and positional power.

19｜Nāgārjuna｜c. 150–250 CE｜India. Main structural contribution: He developed Madhyamaka, using emptiness and dependent origination to criticise substantialism. Principal inheritances and responses: Early Buddhist dependent origination and Mahāyāna Prajñāpāramitā thought The genuinely new structure: He treated emptiness as a way to undo the reification of concepts, developing the two truths and the Middle Way into a system.

20｜Wang Bi｜226–249｜China. Main structural contribution: He reinterpreted Laozi and Zhuangzi through the relation between non-being and being, developing xuanxue philosophy. Principal inheritances and responses: Laozi, Zhuangzi and the Book of Changes The genuinely new structure: He made non-being an underlying condition of the existence of things, forming a systematic metaphysical framework.

21｜Augustine｜354–430｜Roman Empire/North Africa. Main structural contribution: He deepened philosophical inquiry into time, will, memory and inward subjectivity. Principal inheritances and responses: Christian tradition and Neoplatonism The genuinely new structure: He turned the search for truth inward, shaping the prehistory of Western philosophy of the subject through will, memory and lived time.

22｜Fazang｜643–712｜China. Main structural contribution: He developed the relational ontology of Huayan Buddhism. Principal inheritances and responses: The Avataṃsaka Sūtra and Chinese Buddhist traditions of doctrinal classification The genuinely new structure: He developed mutual dependence without erasing difference into a comprehensive structure in which each particular relates to the whole.

23｜Śaṅkara｜Around the eighth century; traditionally 788–820｜India. Main structural contribution: He systematically established Advaita Vedānta. Principal inheritances and responses: The Upanishads, Brahma Sūtras and precursors of Advaita The genuinely new structure: He treated Brahman as the sole ultimate reality and used ignorance to explain the relation between diverse experience and ultimate unity.

24｜Al-Farabi｜c. 872–950｜Islamic world. Main structural contribution: He developed a systematic philosophy linking reason, politics and religion. Principal inheritances and responses: Plato, Aristotle and Neoplatonism The genuinely new structure: He placed philosophical truth, revelation and the political community in a unified hierarchy, shaping Islamic political philosophy.

25｜Avicenna｜980–1037｜Persian/Islamic world. Main structural contribution: He distinguished essence from existence and proposed the Necessary Existent. Principal inheritances and responses: Aristotle, Neoplatonism and Al-Farabi The genuinely new structure: He separated what a thing is from whether it exists, using necessity and possibility to build a new metaphysical structure.

26｜Anselm｜c. 1033–1109｜Medieval Europe. Main structural contribution: He made the relation between concepts, existence and necessity a central philosophical question. Principal inheritances and responses: Augustine and Christian theology The genuinely new structure: He attempted to derive necessary existence from the concept of existence alone, initiating a highly formal ontological argument.

27｜Zhu Xi｜1130–1200｜China. Main structural contribution: He integrated principle, vital force, nature and mind in a Neo-Confucian metaphysics. Principal inheritances and responses: Zhou Dunyi, Zhang Zai, the Cheng brothers and classical Confucianism The genuinely new structure: He developed the relation between principle and vital force into a system explaining cosmos, personality, knowledge and cultivation.

28｜Averroes｜1126–1198｜Al-Andalus/Islamic world. Main structural contribution: He systematically examined the relations among reason, philosophy and religion. Principal inheritances and responses: Aristotle, Islamic theology and philosophy The genuinely new structure: He strengthened the independent standing of philosophical argument and developed an interpretive framework reconciling revelation with rational truth.

29｜Thomas Aquinas｜1225–1274｜Italy/Medieval Europe. Main structural contribution: He developed accounts of existence, causation and natural law. Principal inheritances and responses: Aristotle, Augustine and Avicenna The genuinely new structure: He integrated the act of being, natural ends and theology into a highly systematic Christian Aristotelianism.

30｜William of Ockham｜c. 1287–1347｜England. Main structural contribution: He weakened the ontological standing of universals through nominalism and parsimony. Principal inheritances and responses: Scholastic philosophy and the Scotist tradition The genuinely new structure: He recast universals as concepts or signs and advanced attention to individuals and experience through ontological restraint.

31｜Niccolò Machiavelli｜1469–1527｜Italy. Main structural contribution: He relatively separated the workings of politics from traditional virtue ethics. Principal inheritances and responses: Classical historiography, Roman political experience and medieval advice to princes The genuinely new structure: He treated the preservation of power, institutions and circumstances as independent objects of analysis, opening modern political realism.

32｜Wang Yangming｜1472–1529｜China. Main structural contribution: He reconstructed the moral subject through mind as principle, the extension of innate knowledge and the unity of knowledge and action. Principal inheritances and responses: Mencius, Lu Jiuyuan and Zhu Xi The genuinely new structure: He moved the ground of norms from external investigation to the subject's own moral awareness, rejecting a fundamental separation of knowing and acting.

33｜Francis Bacon｜1561–1626｜England. Main structural contribution: He systematically emphasised experience, experiment and induction. Principal inheritances and responses: Aristotelian tradition and Renaissance natural inquiry The genuinely new structure: He designed knowledge production as a collective and procedural empirical practice linked to changing nature.

34｜Thomas Hobbes｜1588–1679｜England. Main structural contribution: He built the state from individuals, self-interest, fear and contract. Principal inheritances and responses: Mechanistic natural philosophy and early modern natural law The genuinely new structure: He reconstructed political order from atomised persons and a contract model, treating the state as an artificial mechanism.

35｜René Descartes｜1596–1650｜France. Main structural contribution: He established modern philosophy of the subject through methodical doubt and the cogito. Principal inheritances and responses: Scholasticism, mathematical method and scepticism The genuinely new structure: He made self-consciousness the ultimate starting point of certainty and established modern divisions between subject and object, mind and matter.

36｜Baruch Spinoza｜1632–1677｜Netherlands. Main structural contribution: He developed a monism of substance. Principal inheritances and responses: Descartes, Jewish philosophy and scholasticism The genuinely new structure: He replaced mind–body dualism with one substance and redefined freedom as the understanding of necessity.

37｜John Locke｜1632–1704｜England. Main structural contribution: He developed empiricist epistemology and theories of personal identity and rights. Principal inheritances and responses: Hobbes, natural law and questions posed by Descartes The genuinely new structure: He systematically traced knowledge to experience and linked personal identity to continuity of consciousness rather than an immaterial soul.

38｜Gottfried Wilhelm Leibniz｜1646–1716｜German lands. Main structural contribution: He developed monadology, the principle of sufficient reason and possible worlds. Principal inheritances and responses: Descartes, Spinoza and scholastic philosophy The genuinely new structure: He explained unity and multiplicity through indivisible centres of representation and described actuality as the best realised possible world.

39｜George Berkeley｜1685–1753｜Ireland. Main structural contribution: He systematically challenged the notion of independent material substance. Principal inheritances and responses: Lockean empiricism and criticism of abstract ideas The genuinely new structure: He tied existence directly to perception and perceiving subjects, seeking to remove material substance as an intermediary.

40｜David Hume｜1711–1776｜Scotland. Main structural contribution: He systematically questioned causation, self, induction and the foundations of reason. Principal inheritances and responses: Locke, Berkeley and Newtonian empirical science The genuinely new structure: He traced causal necessity to habitual expectation, understood the self as a bundle of perceptions and showed that induction lacks a proof by pure reason.

41｜Jean-Jacques Rousseau｜1712–1778｜Geneva/French-speaking tradition. Main structural contribution: He reconstructed the relations among natural humanity, society, freedom and political legitimacy. Principal inheritances and responses: Natural law, Hobbes, Locke and Enlightenment thought The genuinely new structure: He used the general will to explain political autonomy, making obedience to common law compatible with freedom.

42｜Immanuel Kant｜1724–1804｜Prussia. Main structural contribution: He reconstructed knowledge, morality and aesthetics through transcendental philosophy. Principal inheritances and responses: Hume, the Leibniz–Wolff tradition and Rousseau The genuinely new structure: He located the conditions of possible experience in the subject's a priori structures, distinguishing phenomena from things in themselves and redrawing reason's limits.

43｜Johann Gottlieb Fichte｜1762–1814｜German lands. Main structural contribution: He developed the subject into an active, self-positing principle. Principal inheritances and responses: Kant The genuinely new structure: He made the activity of the I the system's starting point, explaining knowledge and practice through its relation to the not-I.

44｜G. W. F. Hegel｜1770–1831｜German lands. Main structural contribution: He constructed a system centred on conceptual development, negation and historical unfolding. Principal inheritances and responses: Kant, Fichte, Schelling and Greek philosophy The genuinely new structure: He made contradiction and negation internal to the movement of concepts, understanding logic, history, society and spirit as one developmental process.

45｜Friedrich Wilhelm Joseph Schelling｜1775–1854｜German lands. Main structural contribution: He attempted to unify nature and spirit. Principal inheritances and responses: Kant and Fichte The genuinely new structure: He understood nature as a dynamic process capable of producing subjectivity and explored a common ground prior to subject and object.

46｜Arthur Schopenhauer｜1788–1860｜German lands. Main structural contribution: He explained the deeper dynamic of the world through will. Principal inheritances and responses: Kant, Plato and Indian thought The genuinely new structure: He reinterpreted the thing in itself as irrational will, explaining suffering, aesthetic experience and release through desire.

47｜Auguste Comte｜1798–1857｜France. Main structural contribution: He developed positivism and a system of social science. Principal inheritances and responses: Enlightenment thought, Saint-Simon and modern science The genuinely new structure: He restricted the legitimacy of knowledge to empirically investigable regularities and made society itself the object of a systematic science.

48｜John Stuart Mill｜1806–1873｜Britain. Main structural contribution: He developed utilitarianism, the liberty principle and modern liberal ethics. Principal inheritances and responses: Bentham, James Mill and empiricism The genuinely new structure: He combined utility with individual freedom and personal development, distinguishing qualities of pleasure to revise early utilitarianism.

49｜Søren Kierkegaard｜1813–1855｜Denmark. Main structural contribution: He placed individual existence, choice, anxiety and faith at philosophy's centre. Principal inheritances and responses: Hegel, Christian tradition and Socrates The genuinely new structure: He countered totalising philosophy with the single individual and existential choice, laying a structure for existentialism.

50｜Karl Marx｜1818–1883｜German lands. Main structural contribution: He explained history through modes of production, class, praxis and social relations. Principal inheritances and responses: Hegel, Feuerbach, classical political economy and socialist thought The genuinely new structure: He situated consciousness and society within material relations of production and made praxis a real mechanism of structural change.

51｜Charles Sanders Peirce｜1839–1914｜United States. Main structural contribution: He founded pragmatism and modern semiotics and developed abductive inference. Principal inheritances and responses: Kant, logic and scientific practice The genuinely new structure: He developed a triadic relation of sign, object and interpretant and tied conceptual meaning to conceivable practical consequences.

52｜William James｜1842–1910｜United States. Main structural contribution: He developed pragmatism and radical empiricism. Principal inheritances and responses: Peirce, empiricism and psychology The genuinely new structure: He understood experience as a continuum more basic than the subject–object divide and truth as a relation confirmed in practice.

53｜Friedrich Nietzsche｜1844–1900｜German lands. Main structural contribution: He challenged received truth and morality through genealogy and the revaluation of values. Principal inheritances and responses: Schopenhauer, Greek thought and criticism of Christianity The genuinely new structure: He made the history of values themselves an object of inquiry, replacing fixed moral foundations with relations of power, life and interpretation.

54｜Gottlob Frege｜1848–1925｜Germany. Main structural contribution: He developed modern predicate logic and reconstructed questions of sense and reference. Principal inheritances and responses: Mathematics, Aristotelian logic and Leibniz's logical ideal The genuinely new structure: He invented quantified function–argument logic and distinguished sense from reference, establishing a technical basis for analytic philosophy.

55｜Edmund Husserl｜1859–1938｜Germany. Main structural contribution: He founded phenomenology. Principal inheritances and responses: Brentano, Descartes and Kant The genuinely new structure: He used bracketing and phenomenological reduction to study the intentional constitution of consciousness, making how things appear a rigorous philosophical method.

56｜John Dewey｜1859–1952｜United States. Main structural contribution: He developed a practical empiricism and instrumentalism. Principal inheritances and responses: James, Peirce, Hegel and Darwin The genuinely new structure: He understood knowing as an organism's activity in solving environmental problems, weakening a rigid theory–practice divide.

57｜Henri Bergson｜1859–1941｜France. Main structural contribution: He distinguished spatialised time from duration. Principal inheritances and responses: Empiricism, evolutionary theory and modern accounts of time The genuinely new structure: He made indivisible continuity the basic temporal structure of consciousness and life, resisting the reduction of time to a spatial sequence.

58｜Alfred North Whitehead｜1861–1947｜Britain. Main structural contribution: He developed process philosophy. Principal inheritances and responses: Mathematical logic, Plato, Leibniz and modern science The genuinely new structure: He replaced static substance with events, processes and relations, treating generative actual occasions as reality's basic units.

59｜Bertrand Russell｜1872–1970｜Britain. Main structural contribution: He advanced logicism and logical analysis. Principal inheritances and responses: Frege, Leibniz and British empiricism The genuinely new structure: He used logical form to uncover the structure behind ordinary sentences; the theory of descriptions became a model analytic method.

60｜Ludwig Wittgenstein｜1889–1951｜Austria/Britain. Main structural contribution: He reshaped philosophy of language twice, in his early and later work. Principal inheritances and responses: Frege and Russell The genuinely new structure: Early on, he explained language through logical picturing; later, he located meaning in language games, forms of life and use.

61｜Martin Heidegger｜1889–1976｜Germany. Main structural contribution: He reopened the question of being and developed an analysis of Dasein. Principal inheritances and responses: Husserl, Aristotle and Kierkegaard The genuinely new structure: He distinguished being from beings and rebuilt the starting point of ontology through being-in-the-world, care and temporality.

62｜Rudolf Carnap｜1891–1970｜Germany/United States. Main structural contribution: He developed logical analysis into a systematic philosophical method. Principal inheritances and responses: Frege, Russell, Wittgenstein and the Vienna Circle The genuinely new structure: He recast many philosophical disputes as choices of linguistic framework and advanced logical syntax and semantics.

63｜Karl Popper｜1902–1994｜Austria/Britain. Main structural contribution: He reconstructed philosophy of science through falsifiability. Principal inheritances and responses: Hume, Kant, the Vienna Circle and scientific practice The genuinely new structure: He replaced verification with refutability as a criterion of demarcation and viewed the growth of knowledge as conjecture and criticism.

64｜Jean-Paul Sartre｜1905–1980｜France. Main structural contribution: He systematised existentialism. Principal inheritances and responses: Husserl, Heidegger and Hegel The genuinely new structure: He understood consciousness as a negating activity and derived radical freedom and responsibility from the priority of existence over essence.

65｜Hannah Arendt｜1906–1975｜Germany/United States. Main structural contribution: She reconstructed political philosophy through action, public space and power. Principal inheritances and responses: Heidegger, Jaspers and ancient Greek political experience The genuinely new structure: She distinguished labour, work and action and understood politics as the common appearance of plural agents in public.

66｜Emmanuel Levinas｜1906–1995｜Lithuania/France. Main structural contribution: He placed the Other before the subject. Principal inheritances and responses: Husserl, Heidegger and Jewish thought The genuinely new structure: He treated ethical responsibility arising in encounter with the Other as more primordial than ontology and self-knowledge.

67｜Maurice Merleau-Ponty｜1908–1961｜France. Main structural contribution: He developed embodied phenomenology. Principal inheritances and responses: Husserl, Heidegger and Gestalt psychology The genuinely new structure: He understood the body as the primary interface between subject and world, rejecting a simple divide between pure consciousness and objective body.

68｜W. V. O. Quine｜1908–2000｜United States. Main structural contribution: He criticised the analytic–synthetic distinction and developed holism about knowledge. Principal inheritances and responses: Carnap, logical empiricism and pragmatism The genuinely new structure: He treated knowledge as a whole network tested against experience and brought philosophy into closer continuity with natural science.

69｜Claude Lévi-Strauss｜1908–2009｜France. Main structural contribution: He systematically applied structuralism to culture and human thought. Principal inheritances and responses: Saussurean linguistics, Durkheim and Mauss The genuinely new structure: He explained kinship, myth and other cultural phenomena through deep relational structures rather than isolated contents or intentions.

70｜John Rawls｜1921–2002｜United States. Main structural contribution: He rebuilt normative political philosophy through the original position and veil of ignorance. Principal inheritances and responses: Kant, social contract thought and debates over utilitarianism The genuinely new structure: He devised a fair procedure for selecting principles of justice, giving institutional justice a systematic basis beyond utilitarianism.

71｜Thomas Kuhn｜1922–1996｜United States. Main structural contribution: He changed views of scientific development through paradigms and scientific revolutions. Principal inheritances and responses: History of science, Popper and the background of logical empiricism The genuinely new structure: He understood scientific progress as an alternation of normal science and paradigm change, rather than continuous accumulation under one set of rules.

72｜Gilles Deleuze｜1925–1995｜France. Main structural contribution: He developed concepts of difference, becoming, multiplicity and the rhizome. Principal inheritances and responses: Nietzsche, Spinoza, Bergson and Hume The genuinely new structure: He made difference itself, rather than identity, a starting point and replaced centralised, tree-like order with multiple processes of becoming.

73｜Michel Foucault｜1926–1984｜France. Main structural contribution: He developed a framework analysing knowledge, power and subject formation. Principal inheritances and responses: Nietzsche, structuralism and history of science The genuinely new structure: Through archaeology and genealogy, he showed how regimes of truth and subjects are produced together in historical practices.

74｜Hilary Putnam｜1926–2016｜United States. Main structural contribution: He proposed functionalism and semantic externalism in debates on mind, language and realism. Principal inheritances and responses: Analytic philosophy, Quine and philosophy of science The genuinely new structure: He defined mental states through functional roles and changed how meaning relates to environment by arguing that it is not solely in the head.

75｜Jürgen Habermas｜1929–｜Germany. Main structural contribution: He reconstructed modern rationality through communicative reason, the public sphere and discourse ethics. Principal inheritances and responses: Frankfurt School, Weber, Kant and philosophy of language The genuinely new structure: He moved reason from the isolated subject to arguable interaction among subjects, linking normative legitimacy to public argument.

76｜Jacques Derrida｜1930–2004｜France. Main structural contribution: He challenged fixed meaning and centred structures through deconstruction and différance. Principal inheritances and responses: Heidegger, Husserl and structuralism The genuinely new structure: He showed that concepts depend on difference and deferral, making the internal instability of binary oppositions a method of analysis.

77｜John Searle｜1932–2025｜United States. Main structural contribution: He connected speech acts, intentionality, consciousness and social reality. Principal inheritances and responses: Austin, Wittgensteinian traditions and analytic philosophy The genuinely new structure: He systematically developed speech-act classification, collective intentionality and institutional facts, and used the Chinese Room to distinguish syntax from understanding.

78｜Thomas Nagel｜1937–｜United States. Main structural contribution: He emphasised the first-person character of consciousness that resists complete reduction. Principal inheritances and responses: Analytic philosophy, philosophy of mind and anti-reductionism The genuinely new structure: By asking what it is like to be something, he clarified the explanatory gap between subjective experience and third-person physical description.

79｜Saul Kripke｜1940–2022｜United States. Main structural contribution: He reconstructed modal logic, reference theory and metaphysics. Principal inheritances and responses: Frege, Russell and logical semantics The genuinely new structure: With rigid designation and possible-world semantics, he explained a posteriori necessity and broke the assumed link between necessity and the a priori.

80｜Derek Parfit｜1942–2017｜Britain. Main structural contribution: He reconstructed personal identity, reasons and intergenerational ethics. Principal inheritances and responses: Hume, utilitarianism and analytic ethics The genuinely new structure: He reduced personal identity to psychological continuity and showed that strict identity need not be central to survival or responsibility.

81｜Daniel Dennett｜1942–2024｜United States. Main structural contribution: He explained consciousness, intentionality and self in naturalistic terms. Principal inheritances and responses: Ryle, Quine, Darwinism and cognitive science The genuinely new structure: Through the intentional stance, multiple drafts and evolution, he explained mind as a system built up through function and mechanism.

82｜Peter Singer｜1946–｜Australia. Main structural contribution: He extended consequentialism systematically to animal ethics, global poverty and applied ethics. Principal inheritances and responses: Bentham, Mill and utilitarianism The genuinely new structure: He moved the boundary of moral concern from species membership to sentient interests and made aid to distant others a demanding ethical question.

83｜Martha Nussbaum｜1947–｜United States. Main structural contribution: She developed the capabilities approach. Principal inheritances and responses: Aristotle, Rawls and Amartya Sen The genuinely new structure: She shifted the measure of justice from resources or utility to what a person is actually able to be and do.

84｜David Chalmers｜1966–｜Australia/United States. Main structural contribution: He formulated the hard problem of consciousness and reopened its metaphysics. Principal inheritances and responses: Kripke, philosophy of mind and cognitive science The genuinely new structure: He sharply separated functional explanation from the explanation of subjective experience and reopened ontology with proposals including naturalistic dualism.

How to use this list

These 84 thinkers are not a ranking of the '84 greatest philosophers'. The narrower question is whether they changed philosophy's basic structure.

The judgement can be organised into three levels.

The first is the creation of foundational structures. These thinkers changed philosophy's starting point, what counts as a basic question, or the most fundamental relations among world, person and knowledge. Plato, Aristotle, Descartes, Kant, Hegel, Husserl, Wittgenstein and Heidegger are typical examples.

The second is the creation of independent systems. These thinkers did not necessarily rebuild philosophy's entire foundation, but developed theoretical structures that cannot simply be reduced to their predecessors. Spinoza, Leibniz, Kierkegaard, Peirce, Whitehead, Foucault, Rawls and Kripke are examples.

The third is the creation of structures within a field. These thinkers redefined problems in ethics, philosophy of language or mind, political philosophy, or philosophy of science. Searle, Nagel, Parfit, Singer, Nussbaum and Chalmers are examples.

A rigorous test of originality asks more than whether a philosopher coined terms or produced a complete body of work. After their main sources are removed, does what remains still constitute a philosophical structure that cannot easily be reduced to them?