Two and a half thousand years of thinking

Philosophy is the attempt to think clearly and systematically about the most basic questions: what exists, what can be known, how one ought to live, what makes a society just, and what reasoning itself is. The word comes from the Greek philosophia, love of wisdom. For most of history it covered almost all rational inquiry, including what would now be called physics, biology and psychology; only in the last few centuries did the natural sciences break away, leaving philosophy with the questions that observation and experiment alone cannot settle.

Philosophy did not begin in one place. Between roughly 800 and 200 BCE, independent traditions of argued reflection arose in Greece, India and China, a coincidence the German philosopher Karl Jaspers called the Axial Age. Other traditions, in the Islamic world, in Africa and elsewhere, grew from these roots or alongside them. This section of the atlas follows those traditions era by era, from the first Greek speculations about nature to the philosophy of the present day, with attention to where ideas were born and how they travelled between cities, empires and languages.

Philosophers usually divide their subject into a few core fields. Metaphysics asks about the fundamental nature of reality: whether there is a God, whether minds are separate from bodies, what causation and time are, and whether human beings have free will. Epistemology, the theory of knowledge, asks what knowing is, how it differs from believing, and whether reason or the senses is the more reliable source. Logic studies the difference between good and bad reasoning, and from Aristotle to modern computing it has been the most technical part of the discipline.

Ethics asks how one should live and what makes actions right or wrong. Some thinkers focus on the consequences of actions, others on duties and rules, others on character and virtue. Political philosophy extends these questions to the state: who should rule, what makes power legitimate, and what citizens owe one another. Aesthetics considers beauty and art. Over time more specialised fields have grown up, including the philosophies of mind, language, science, religion and history.

Different traditions have weighted these branches differently. Classical Chinese thinkers were most concerned with ethics, government and self-cultivation; Indian schools tied metaphysics and theories of knowledge closely to the search for liberation from suffering; Greek and later European philosophy gave unusual weight to logic and to the nature of the physical world.

The Western tradition begins in the Greek cities of the Aegean around 600 BCE. Ancient Greek Philosophy opens with Thales of Miletus and the other Presocratics, who tried to explain the world through natural causes rather than myth, and reaches its height in Athens with Socrates, his pupil Plato and Plato's pupil Aristotle. Between them they defined most of the questions that later Western philosophy would ask.

After the conquests of Alexander the Great, Hellenistic and Roman Philosophy turned towards the art of living well in an uncertain world. The Stoics, Epicureans, Sceptics and Cynics taught in Athens, then in Alexandria and Rome, and found celebrated followers such as Epicurus, Seneca and the emperor Marcus Aurelius. In the third century CE Plotinus founded Neoplatonism, the last great school of pagan antiquity, which ended as an institution when the emperor Justinian closed the school of Athens in 529.

Indian Philosophy has the longest continuous history of any tradition. Its roots lie in the Vedas and the Upanishads, texts that explore the relation between the individual self, atman, and ultimate reality, brahman. In the sixth and fifth centuries BCE, in the kingdoms of the Ganges plain, the Buddha and Mahavira, the great teacher of Jainism, rejected parts of Vedic orthodoxy and offered new paths to release from suffering and rebirth. Over the following centuries Indian thinkers built sophisticated theories of logic, language and knowledge. The Buddhist philosopher Nagarjuna argued that nothing has an independent essence, while Adi Shankara systematised Advaita Vedanta, the teaching that the self and ultimate reality are one. Six classical Hindu schools, along with Buddhist and Jain rivals, debated with each other for over a millennium.

Chinese and East Asian Philosophy took shape in the era of warring states that followed the decline of the Zhou dynasty, when rival rulers welcomed advisers who could offer a recipe for order. Confucius taught that a good society rests on cultivated character, ritual propriety and family duty. The Daoist texts attributed to Laozi and Zhuangzi urged harmony with the Dao, the natural way, and a suspicion of rigid rules. Mozi argued for impartial care for all people, and Legalists such as Han Fei for strict laws and punishments. Buddhism, arriving from India along the Silk Road, transformed Chinese thought, and centuries later Zhu Xi and Wang Yangming reshaped Confucianism into a philosophy of the cosmos and the mind that spread across Korea and Japan. In the twentieth century Nishida Kitarō and the Kyoto School brought Zen Buddhist ideas into dialogue with European philosophy.

Greek philosophy did not die with the closing of the Athenian school. Its texts survived in Constantinople, in Christian Syriac schools and in Alexandria, and from the eighth century the caliphs of the Abbasid Caliphate sponsored a great movement to translate them into Arabic, centred on Baghdad. Islamic and Jewish Philosophy grew from this inheritance. Al-Kindi, Al-Farabi and Avicenna built vast systems that reconciled Aristotle and Neoplatonism with belief in one God; Al-Ghazali challenged their claims; and in Muslim Spain Averroes and the Jewish thinker Maimonides wrote some of the most searching works on faith and reason. Ibn Khaldun later developed a pioneering theory of the rise and fall of states.

In the Latin West, Medieval Christian Philosophy began with Augustine of Hippo, who fused Christian doctrine with Platonism, and Boethius, who preserved part of Aristotle's logic. From the twelfth century translators in Toledo and elsewhere turned Arabic and Greek works into Latin, giving the new universities of Paris and Oxford the full Aristotle along with Arabic commentaries. Thomas Aquinas built the most influential synthesis of Aristotle and Christian theology, and William of Ockham questioned much of it in the fourteenth century. This chain of transmission, from Greek into Syriac and Arabic and then into Latin, is one of the clearest examples of how traditions are connected.

Renaissance Philosophy began in the Italian cities of the fourteenth century, where humanists recovered classical texts and Greek scholars arriving from Byzantium taught Plato in the original. Niccolò Machiavelli analysed power without moral illusions, Erasmus championed humane learning and reform, and Michel de Montaigne, reading the ancient Sceptics, invented the personal essay.

Early Modern Philosophy, shaped by the Scientific Revolution, set out to rebuild knowledge on secure foundations. René Descartes, Baruch Spinoza and Gottfried Wilhelm Leibniz trusted reason, while John Locke and David Hume insisted that all knowledge comes from experience. The Enlightenment turned this critical spirit on religion, government and society through Voltaire, Jean-Jacques Rousseau and Adam Smith, and Immanuel Kant tried to settle the quarrel between reason and experience by examining the limits of the mind itself.

Nineteenth-Century Philosophy responded to Kant and to the upheavals of revolution and industry. Georg Wilhelm Friedrich Hegel saw history as the unfolding of reason; Karl Marx recast this as a history of economic struggle; John Stuart Mill defended liberty and the greatest happiness; Søren Kierkegaard and Friedrich Nietzsche attacked the comfortable certainties of their age.

In the twentieth century Western philosophy divided into two broad styles. Analytic Philosophy, founded on the new logic of Gottlob Frege and Bertrand Russell, prized precision and the analysis of language, and produced figures such as Ludwig Wittgenstein and John Rawls. Continental Philosophy, growing from the phenomenology of Edmund Husserl and Martin Heidegger, explored existence, freedom and history through Jean-Paul Sartre, Simone de Beauvoir, Hannah Arendt and Michel Foucault. The division has softened in recent decades.

African and Africana Philosophy spans the oldest written wisdom literature and some of the liveliest debates of the present. Egyptian instruction texts, such as those attributed to the vizier Ptahhotep, reflected on justice, order and right conduct long before the Greeks. In seventeenth-century Ethiopia, Zera Yacob wrote a reasoned critique of religious authority. Oral traditions across the continent carried ethical ideas such as ubuntu, the southern African principle that a person becomes a person through other people. In the twentieth century African and diaspora thinkers debated whether such shared worldviews count as philosophy, while Frantz Fanon and others analysed colonialism and its psychological effects.

These traditions are often told as separate stories, but they touched more than is commonly assumed. Greek and Indian thought met in the kingdoms founded after Alexander's conquests, and Buddhism carried Indian ideas across Central Asia to China, Korea and Japan. Greek philosophy passed through Syriac and Arabic into Latin, so that medieval Europe read Aristotle with the help of Muslim and Jewish commentators. European thinkers of the Enlightenment read translations of Confucius, and nineteenth-century philosophers such as Arthur Schopenhauer drew on Indian texts. In the modern era, African, Asian and Latin American philosophers have engaged critically with European traditions while recovering their own.

The pages of this section treat each era and tradition in turn, describing its historical setting, its leading thinkers and what they argued, and listing the philosophers on the atlas who belong to it.