550 BC Confucius teaches practical philosophy
K'ung-fu-tzu, or Confucius, teaches a practical philosophy which will profoundly influence Chinese history

500 BC Parmenides puts the logic in philosophy
Parmenides is the first pure philosopher, using logic as a philosophical tool in his poem Nature

500 BC Chinese compare yin with yang
The Chinese philosophy of alternating opposites is expressed as yin and yang

450 BC Sophists wander round Greece
The Sophists, professional philosophers, travel round Greece educating the sons of the rich

423 BC Socrates satirized by Aristophanes
Socrates is now sufficiently prominent to be satirized in Clouds, a comedy by Aristophanes

400 BC Daodejing shows the way
Daodejing ('The Way and the Power') is the book of Daoism

399 BC Socrates drinks hemlock
Socrates, convicted in Athens of impiety, is sentenced to death and drinks the hemlock

387 BC Plato as schoolmaster in Athens
Plato establishes a school in Akademeia, a suburb of Athens

380 BC Plato's theory of forms
Central to Plato's philosophy is the theory that there are higher Forms of reality, of which our senses perceive only a transient shadow

367 BC Aristotle in Plato's school
Aristotle, at the age of seventeen, comes to Athens to join Plato's academy

330 BC Aristotle's encyclopedic approach
Aristotle tackles wide-ranging subjects on a systematic basis, leaving to his successors an encyclopedia of contemporary thought

170 Marcus Aurelius meditates
Marcus Aurelius is rare among emperors in writing twelve books of philosophical Meditations

244 Plotinus moves to Rome
Plotinus, moving from Alexandria to Rome, teaches the influential philosophy later known as Neo-Platonism

413 Augustine emphasizes City of God
Prompted by the fall of Rome to the Visigoths, St Augustine undertakes a great work of Christian philosophy, the City of God

525 Boethius consoled by philosophy
Boethius, in prison in Pavia and awaiting execution, writes the Consolation of Philosophy

529 Philosophy schools closed in Athens
Justinian closes down the schools of Athens, famous for their tradition of pagan philosophy

930 Saadiah's Book of Beliefs
Saadiah Gaon writes a seminal work of Jewish philosophy in his Book of Beliefs and Opinions

1020 Avicenna in Isfahan
The Persian scholar Avicenna, author of encyclopedic works on philosophy and medicine, spends the last part of his life in Isfahan

1078 Anselm claims to prove that God exists
Anselm includes in his Proslogion his famous 'ontological proof' of the existence of God

1180 Averroës in Cordoba
In Cordoba the Muslim philosopher Averroës writes commentaries on Aristotle that are influential throughout medieval Europe

1180 Maimonides in Cairo
In Cairo the Jewish philosoper Moses Maimonides writes, in Arabic, a much translated text with the endearing title Guide to the Perplexed

1266 Thomas Aquinas and scholasticism
Thomas Aquinas begins the outstanding work of medieval scholasticism, his Summa Theologiae

1300 Duns Scotus, genius or dunce
Duns Scotus, known as the Subtle Doctor in medieval times, later provides humanists with the name Dunsman or dunce

1340 Ockham's Razor
William of Ockham advocates paring down arguments to their essentials, an approach later known as Ockham's Razor

1462 Platonic Academy in Florence
In keeping with his personal interest in Plato, Cosimo de' Medici founds a Platonic Academy in Florence

1595 Europe hears news of Confucius
The writings of Matteo Ricci introduce Kung Fu Tzu to Europe under a Latin version of his name - Confucius

1644 Descartes thinks so he is
In his Principles of Philosophy Descartes gives priority to reason, summed up in his famous phrase cogito ergo sum

1677 Spinoza's Ethics
Baruch Spinoza's Ethics, dealing with God, the mind and the emotions, is published shortly after his death

1690 Locke on human understanding
John Locke publishes his Essay concerning Human Understanding, arguing that all knowledge is based on experience

1710 Berkeley attacks Locke
25-year-old George Berkeley attacks Locke in his Treatise Concerning the Principles of Human Knowledge

1714 Leibniz discusses monads
In his Monadology Leibniz describes a universe consisting of forceful interactive parts that he calls 'monads'

1739 Hume ponders human nature
David Hume publishes his Treatise of Human Nature, in which he applies to the human mind the principles of experimental science

1762 Calls for Rousseau's arrest
Two books in this year, Émile and Du Contrat Social, prompt orders for the arrest of Jean-Jacques Rousseau

1781 Kant on pure reason
German philosopher Immanuel Kant publishes the first of his three 'critiques', The Critique of Pure Reason

1789 Bentham expounds utilitarianism
In his Principles Jeremy Bentham defines 'utility' as that which enhances pleasure and reduces pain

1794 Fichte analyzes knowledge
In his Science of Knowledge Johann Gottlieb Fichte contrasts the I, or Ego, and its opposing non-I, or non-Ego

1807 Hegel charts development of mind
In Phenomenology of Spirit Friedrich Hegel interprets history as the advance of the human mind, often through thesis, antithesis and synthesis

1818 Schopenhauer is pessimistic
In The World as Will and Idea Schopenhauer develops the bleakest possible view of the effects of the human will

1836 Emerson defines Transcendentalism
In his essay, Nature, Ralph Waldo Emerson sets out the fundamentals of the philolosphy of Transcendentalism

1840 Transcendental Club publishes The Dial
The first issue of the quarterly magazine The Dial is issued by the Transcendentalists meeting at Ralph Waldo Emerson's home

1845 Kierkegaard makes subjective experience central
With his emphasis on the subjective experience of human Existenz, the Danish philosopher Kierkegaard plants the seed of existentialism

1859 John Stuart Mill On Liberty
In On Liberty John Stuart Mill makes the classic liberal case for the priority of the freedom of the individual

1862 Prolific year for Emily Dickinson
Unpublished American poet Emily Dickinson writes more than 300 poems within the year

1872 Pragmatism in Metaphysical Club
Pragmatism emerges as a philosophical approach in meetings of the Metaphysical Club in Cambridge, Massachusetts

1883 Nietzsche and 'superman'
In Thus Spake Zarathustra Friedrich Wilhelm Nietzsche envisages the Übermensch ('superman') enhancing human existence

1884 Frege's Foundations of Arithmetic
German mathematician Gottlob Frege publishes Grundlagen der Arithmetik ('Foundations of Arithmetic'), linking mathematics and logic

1902 William James analyses religious experience
US philosopher William James publishes his influential book The Varieties of Religious Experience

1903 Principia Ethica
British philosopher G.E. Moore publishes Principia Ethica, an attempt to apply logic to ethics

1905 Santayana's Life of Reason
US philosopher George Santayana publishes the first of the five volumes of his Life of Reason

1907 William James advocates pragmatism
US philosopher William James publishes Pragmatism: a New Name for Old Ways of Thinking

1912 Wittgenstein studies with Russell
Ludwig Wittgenstein moves to Cambridge to study philosophy under Bertrand Russell

1913 Principia Mathematica
Alfred North Whitehead and Bertrand Russell complete a work of mathematical logic, Principia Mathematica

1921 Tractatus Logico Philosophicus
Ludwig Wittgenstein publishes his influential study of the philosophy of logic, Tractatus Logico Philosophicus

1923 Buber's I and Thou
In I and Thou the Austrian theologian Martin Buber interprets religion in terms of the subjective experience of interpersonal relationships

1927 Heidegger and Dasein
In Being and Time German philosopher Martin Heidegger makes an existentialist case with Dasein ('Being There') as the central theme

1936 Ayer and Logical Positivism
In Language, Truth and Logic 26-year-old A.J. Ayer produces a classic exposition of Logical Positivism

1943 Sartre defines existentialism
French philosopher Jean-Paul Sartre expounds his theory of existentialism in Being and Nothingness ('L'Être et le néant')

1945 The Open Society and its Enemies
Austrian philosopher Karl Popper publishes The Open Society and its Enemies