History of Western philosophy

For Bertrand Russell's History of Western Philosophy (and its connection with political and social circumstances from the earliest times to the present day), see History of Western Philosophy (Russell)

Western philosophy has a long history conventionally divided into three large eras: the Ancient, Medieval and Modern. The Ancient era runs through the fall of Rome and includes the Greek philosophers such as Plato. The Medieval period runs until roughly the late 1400s and the Renaissance. The "Modern" is a word with more varied use, which includes everything from Post-Medieval through the specific period of the early 20th century.

Brief timeline

Ancient philosophy

Western Philosophy is generally said to begin in the Greek cities of western Asia Minor (Ionia) with Thales of Miletus, who was active around 585 B.C. and left us the opaque dictum, "All is water." His most noted students were Anaximenes of Miletus and Anaximander ("All is air").

Other thinkers and schools appeared throughout Greece over the next couple of centuries. Among the most important were:

Heraclitus, who stressed the transitory and chaotic nature of all things ("All is fire"; "We cannot step into the same river twice").

Anaxagoras, who asserted that reality was so ordered that it must be in all respects governed by Mind.

The Pluralists and Atomists (Empedocles, Democritus) who tried to understand the world as composite of innumerable interacting parts; and the Eleatics Parmenides and Zeno who both insisted that All is One and change is impossible. Parmenides and his school emphasized the enduring, perduring, and absolute character of the world and of truth. ("To be is, to not be is not.")

The Sophists, traveling professional teachers of varied philosophical affinity, became known (perhaps unjustly) for claiming that truth was no more than opinion and for teaching people to argue fallaciously to prove whatever conclusions they wished.

This whole movement gradually became more concentrated in Athens, which had become the dominant city-state in Greece.

There is considerable discussion about why Athenian culture encouraged philosophy, but one popular theory says that it occurred because Athens had a direct democracy. It's known from Plato's writings that many sophists maintained schools of debate, were respected members of society, and were well paid by their students. It's also well known that orators had tremendous influence on Athenian history, possibly even causing its failure (See Battle of Miletus). One other theory for the popularity of philosophical debate in Athens was due to the use of slavery there - the workforce, mainly slaves, performed the labour that otherwise would have been taken up by the male population of the city. Freed from working in the fields or in productive activity, they were then free to engage in the assemblies of Athens, and spend long hours discussing popular philosophical questions. The theory fills in the blanks by saying that the Sophists' students wanted to acquire the skills of an orator in order to influence the Athenian Assembly, and thereby grow wealthy and respected. Since winning debates led to wealth, the subjects and methods of debate became highly developed.

The key figure in transforming Greek philosophy into a unified and continuous project - the one still being pursued today - is Socrates, who studied under several Sophists. He then spent much of his life, we are told, engaging everyone in Athens in discussion trying to determine whether anyone had a very good idea what they were talking about, especially when they talked about important matters like justice, beauty and truth. He wrote nothing, but inspired many disciples. In his old age he became the focus of the hostility of many in the city who saw philosophy and sophistry, interchangeably, as destroying the piety and moral fiber of the city; he was executed in 399 B.C.

His most important student was Plato, who wrote a number of philosophical dialogues using his master's methods of inquiry to examine problems. The early dialogues demonstrate something like Socrates' own fairly inconclusive style of inquiry. The "middle" ones develop a substantive metaphysical and ethical system to resolve these problems. Central ideas are the Theory of Forms, that the mind is imbued with an innate capacity to understand and apply concepts to the world, and that these concepts are in a significant way more real, or more basically real, than the things of the world around us; the immortality of the soul, and the idea that it too is more important than the body; the idea that evil is a kind of ignorance, that only knowledge can lead to virtue, that art should be subordinate to moral purposes, and that society should be ruled by a class of philosopher kings. In the later dialogues Socrates figures less prominently, and the Theory of Forms is cast in doubt; more directly ethical questions become the focus. Interestingly, in his most famous work, The Republic Plato attacks the system of democracy, blaming it for the defeat of Athens in the Peloponnesian War - he attributes the indecision of the masses (who voted on everything, including military strategy) as the reason for military defeat. He proposed instead a three tiered structure of society, with workers, guardians and philosophers, in ascending order of importance (convenient for him and his disciples, clearly), citing the philosophers greater knowledge of the forms as the reason for them being more appropriate in running society.

Plato founded the Academy of Athens, and his most outstanding student there was Aristotle. Possibly Aristotle's most important and long-lasting work was his formalization of logic. It appears that Aristotle was the first philosopher to categorize every valid syllogism. A syllogism is a form of argument that is guaranteed to be accepted, because it is known (by all educated persons) to be valid. A crucial assumption in Aristotelian logic is that it has to be about real objects. Two of Aristotle's syllogisms are invalid to modern eyes. For example, "All A are B. All A are C. Therefore, some B are C." This syllogism fails if set A is empty.

Medieval philosophy

Medieval philosophy was greatly concerned with the nature of God, and the application of Aristotle's logic and thought to every area of life.

If God exists at all, surely He is the most important feature of the universe, and therefore worthy of study. One continuing interest in this time was to prove the existence of God, through logic alone, if possible.

One early effort was the cosmological argument, conventionally attributed to Thomas Aquinas. The argument roughly, is that everything that exists has a cause. Therefore, there must be an uncaused first cause, and this is God. Aquinas also adapted this argument to prove the goodness of God. Everything has some goodness, and the cause of each thing is better than the thing caused. Therefore, the first cause is the best possible thing. Similar arguments are used to prove God's power and uniqueness.

Another important argument proof of the existence of God was the Ontological Argument, advanced by St. Anselm. Basically, it says that God has all possible good features. Existence is good, and therefore God has it, and therefore exists. This argument has been used in different forms by philosophers from Descartes forward.

The application of Aristotelian logic proceeded by having the student memorize a rather large set of syllogisms. The memorization proceeded from diagrams, or learning a key sentence, with the first letter of each word reminding the student of the names of the syllogisms.

Each syllogism had a name, for example "Modus Ponens" had the form of "If A is true, then B is true. A is true, therefore B is true."

Most university students of logic memorized Aristotle's 19 syllogisms of two subjects, permitting them to validly connect a subject and object. A few geniuses developed systems with three subjects, or described a way of elaborating the rules of three subjects.

As well as Aquinas, other important names from the medieval period include Duns Scotus and Pierre Abélard.

Modern philosophy

As with many periodizations, there are multiple current usages for the term "Modern Philosophy" that exist in practice. One usage is to date modern philosophy from the "Age of Reason", where systematic philosophy became common, which excludes Erasmus and Machiavelli as, "modern philosophers". Another is to date it, the way the entire larger modern period is dated, from the Renaissance. In some usages, "Modern Philosophy" ended in 1800, with the rise of Hegelianism and Idealism. There is also the lumpers/splitters problem, namely that some works split philosophy into more periods than others: one author might feel a strong need to differentiate between "The Age of Reason" or "Early Modern Philosophers" and "The Enlightenment", another author might write from the perspective that 1600-1800 is essentially one continuous evolution, and therefore a single period. Wikipedia's philosophy section therefore hews more closely to centuries as a means of avoiding long discussions over periods, but it is important to note the variety of practice that occurs.

A broad overview would then have Erasmus, Francis Bacon, Niccolò Machiavelli, and Galileo Galilei represent the rise of empiricism and humanism in place of scholastic tradition. 17th-century philosophy is dominated by the need to organize philosophy on rational, skeptical, logical and axiomatic grounds, such as the work of René Descartes, Blaise Pascal and Thomas Hobbes, attempting to integrate religious belief into philosophical frameworks, and, often to combat atheism or other unbelief, by adopting the idea of material reality, and the dualism between spirit and material. The extension, and reaction, against this would be the monism of George Berkeley and Benedict de Spinoza.

The 18th-century philosophy article deals with the period often called the early part of "The Enlightenment" in the shorter form of the word, and centers around the rise of systematic empiricism, following after Sir Isaac Newton's natural philosophy. Thus Diderot, Voltaire, Rousseau and culminating with Kant and the political philosophy of the American Revolution are part of The Enlightenment.

The 19th century took the radical notions of self-organization and intrinsic order from Goethe and Kantian metaphysics, and proceeded to produce a long elaboration on the tension between systematization and organic development. Foremost was the work of Hegel, whose Logic and Phenomenology of Spirit produced a "dialectical" framework for ordering of knowledge. The 19th century would also include Schopenhauer's negation of the will. As with the 18th century, it would be developments in science that would arise from, and then challenge, philosophy: most importantly the work of Charles Darwin, which was based on the idea of organic self-regulation found in philosophers such as Adam Smith, but fundamentally challenged established conceptions.

The 20th Century deals with the upheavals produced by a series of conflicts within philosophical discourse over the basis of knowledge, with classical certainties overthrown, and new social, economic, scientific and logical problems. 20th Century philosophy was set for a series of attempts to reform and preserve, and to alter or abolish, older knowledge systems. Seminal figures include Sigmund Freud, Friedrich Nietszche, Ernst Mach, John Dewey. Epistemology and its basis was a central concern, as seen from the work of Heidegger, Karl Popper, Claude Lévi-Strauss and Bertrand Russell. Phenomenologically oriented metaphysics undergirded existentialism (Jean-Paul Sartre, Søren Kierkegaard, Albert Camus) and finally postmodern_philosophy (Jean-François Lyotard, Michel Foucault, Jacques Derrida). Also notable was the rise of "pop" philosophers who promulgated systems for dealing with the world, but which were isolated philosophically, including Ayn Rand, CS Lewis and others.

Chronological list of important philosophers

See also: list of philosophers for a more comprehensive list of philosophers.

Thales (620-546 BC), traditionally the first Presocratic philosopher.
Anaximander (610-540 BC), Ionic Presocratic, the first to write a philosophical treatise.
Anaximenes (fl. 6th cent. BC), Ionic Presocratic, possibly a pupil of Anaximander.
Heraclitus (540-480 BC), Presocratic philosopher of flux.
Pythagoras (570-497 BC), philosopher-mathematician based in Italy.
Theano (fl. 6th cent. BC), female philosopher, pupil of Pythagoras and later his wife.
Xenophanes (570-475 BC), Presocratic philosopher-poet pre-empting the Eleatic school.
Parmenides (510-440 BC), Eleatic philosopher of being.
Anaxagoras (500-428 BC), Presocratic, the first philosopher known to have been based in Athens.
Diogenes Apolloniates (fl. 5th cent. BC), Ionian Presocratic philosopher.
Empedocles (493-433 BC), Presocratic philosopher and cosmologist.
Zeno of Elea (fl. 5th cent. BC), Eleatic philosopher famous for his paradoxes of motion.
Leucippus (fl. 5th cent. BC), Presocratic philosopher, founder of atomism.
Protagoras (485-415 BC), Sophist famous for his relativism.
Hippias (485-415 BC), Sophist.
Gorgias (483-376 BC), Sophist and teacher of rhetoric.
Antiphon (480-411 BC), Orator and Sophist (if these two are in fact the same person), fragments of whose treatise On Truth were discovered at Oxyrhynchus.
Aspasia (fl. 5th cent. BC), female philosopher and rhetorician, companion of Socrates.
Socrates (469-399 BC), Athenian philosopher, put to death on charges of corrupting the youth.
Prodicus (fl. 5th cent. BC), Sophist contemporary with Socrates.
Democritus (460-370 BC), famous atomic philosopher.
Euclid of Megara (450-380 BC), associate of Socrates and founder of the Megarian school.
Antisthenes (445-360 BC), companion of Socrates, often associated with the later Cynic movement.
Aristippus (435-356 BC), companion of Socrates, traditionally the founder of the Cyrenaic school devoted to hedonism.
Plato (429-347 BC), younger associate of Socrates, founder of the Academy, teacher of Aristotle.
Xenophon (427-355 BC), historian and philosophical author, famous for his accounts of Socrates.
Speusippus (407-339 BC), pupil of Plato who succeeded him as second head of the Academy.
Diogenes of Sinope (400-325 BC), Cynic philosopher.
Xenocrates (396-314 BC), follower of Plato and third head of the Academy.
Aristotle (384-322 BC), pupil of Plato, founder of the Lyceum and the Peripatetic tradition.
Arete of Cyrene (fl. 4th cent. BC), daughter of Aristippus and his successor as head of the Cyrenaic school.
Stilpo (380-300 BC), Megarian philosopher, influenced by Cynicism and an influence on Stoicism.
Theophrastus (370-288 BC), pupil of Aristotle and his successor as head of the Lyceum.
Pyrrho (365-275 BC), founder of the sceptical philosophy named after him.
Epicurus (341-270 BC), atomist and hedonist philosopher, founder of school named after him.
Zeno of Citium (335-263 BC), founder of the Stoic school.
Cleanthes (331-232 BC), second head of the Stoic school.
Aristo (fl. 3rd cent. BC), Stoic philosopher, a pupil of Zeno, focused primarily on ethics.
Timon (320-230 BC), sceptical philosopher, pupil of Pyrrho.
Arcesilaus (316-242 BC), head of Plato's Academy, perhaps responsible for its turn towards scepticism.
Menippus (fl. 250 BC), Cynic philosopher and famous as a satirist.
Chrysippus (280-207 BC), third (and probably most important) head of the Stoic school.
Diogenes of Babylon (240-152 BC), Stoic philosopher, member of the famous embassy of philosophers to Rome.
Carneades (214-129 BC), head of the Academy and founder of the 'New Academy', member of the famous embassy of philosophers to Rome.
Panaetius (185-109 BC), Stoic philosopher with eclectic tendencies, pupil of Diogenes of Babylon and Antipater, influence upon Cicero.
Philo of Larissa (160-80 BC), head of the Academy, teacher of Cicero.
Zeno of Sidon (150-70 BC), Epicurean philosopher.
Posidonius (135-51 BC), Stoic philosopher and historian, often characterised as an eclectic representative of the 'Middle Stoa'.
Antiochus of Ascalon (130-68 BC), pupil of Philo of Larissa, head of the Academy turning it away from the scepticism of the 'New Academy' and back to the 'Old Academy'. An important influence upon Cicero.
Philodemus (110-40 BC), Epicurean philosopher, many of whose works were buried at Herculaneum.
Cicero (106-43 BC), Roman philosophical author.
Aenesidemus (fl. 1st cent. BC), sceptical philosopher who attempted to revive Pyrrhonism.
Lucretius (94-55 BC), Epicurean philosopher-poet.
Philo of Alexandria (30 BC - 45 AD), Jewish Hellenistic philosopher and prolific author based in Alexandria.
Seneca (4 BC - 65 AD), Latin Stoic author, onetime tutor to the Emperor Nero.
Musonius Rufus (30-100 AD), Stoic philosopher-preacher.
Plutarch (45-120 AD), biographer and author of an important collection of philosophical essays, the Moralia.
Epictetus (55-135 AD), Stoic philosopher, pupil of Musonius Rufus and founder of a school in Nicopolis.
Demonax (fl. 2nd cent. AD), Cynic philosopher, pupil of Epictetus.
Diogenes of Oenoanda (fl. 2nd cent. AD), author of Epicurean inscription at Oenoanda.
Alcinous (fl. 2nd cent. AD), Platonist and author of the Handbook of Platonism.
Marcus Aurelius (121-180 AD), Roman Emperor and Stoic philosopher.
Galen of Pergamum (129-199 AD), philosopher-doctor influenced by Platonism, physician to Marcus Aurelius, and prolific author.
Clement of Alexandria (150-215 AD), Christian Church Father heavily influenced by Greek philosophy.
Sextus Empiricus (fl. 200 AD), sceptical philosopher and author.
Alexander of Aphrodisias (fl. 200 AD), Aristotelian commentator.
Julia Domna (170-217 AD), female philosopher and wife of the Emperor Septimius Severus, included Galen and Philostratus in her philosophical circle.
Diogenes Laertius (fl. 3rd cent. AD), famous biographer of ancient philosophers.
Plotinus (205-270 AD), Platonic philosopher and founder of Neoplatonism.
Porphyry (233-309 AD), Neoplatonist, pupil and biographer of Plotinus.
Iamblichus (242-327 AD), important Neoplatonic philosopher.
Calcidius (fl. 4th cent. AD), Platonist and author of an important Latin translation and commentary on the Timaeus.
Themistius (317-388 AD), Aristotelian commentator based in Constantinople.
Augustine of Hippo (354-430 AD), Christian philosopher and Church father, influenced by Neoplatonism.
Hypatia (370-415 AD), famous female Neoplatonist based Alexandria and murdered by a Christian mob.
Proclus (411-485 AD), Athenian Neoplatonist and head of the Academy.
Ammonius (440-521 AD), Alexandrian Neoplatonist, a pupil of Proclus and teacher of Damascius and Simplicius.
Damascius (462-540 AD), Neoplatonist and head of the Athenian school.
Boethius (475-524 AD), Latin Neoplatonist and translator of Aristotle.
Simplicius of Cilicia (490-560 AD), Aristotelian commentator, pupil of Damascius.
John Philoponus (490-570 AD), Christian Aristotelian commentator based in Alexandria, pupil of Ammonius.
Johannes Scotus Eriugena (810-877 AD) Also called "John the Scot".
Anselm (11th century) Posed the ontological argument for the existence of God.
Pierre Abélard (1079-1142 AD) Aristotelian (nominalist) lived a great love story similar to Romeo and Juliet.
Roger Bacon (1220-1292 AD) He believed there could and should be a unified science based on observation, experiment and abstract reasoning.
Thomas Aquinas (1224-1274 AD) Tried to merge the already Platonized Christianity with the philosophy of Aristotle maintaining a distinction between philosophy and religion.
Duns Scotus (1266-1308 AD) Heavily criticized Aquinas.
William of Ockham (1285-1347 AD) Observation nature and reason can only provide us with reliable knowledge about the world, famous for his principle of accepting the simplest of alternatives as the best one (Ockham's Razor).
Copernicus (1473-1543 AD) Polish churchman who hypothesized that many mathematical difficulties of the time would disappear if we assumed sun was at the center of our planetary system instead of earth (and flatly contradicting the Bible).
Niccolò Machiavelli (1469-1527 AD) Studied politics and government in an objective (scientific) manner.
Tycho Brahe (1546-1601 AD) Astronomer with vast body of measured astronomical observations passed on the Johannes Kepler.
Francis Bacon (1561-1626 AD) Believed that scientific knowledge could give power of man over nature. He also believed the idea that definitions advance knowledge was an illusion (Aristotle's idea?).
Galileo Galilei (1564-1642 AD) Widely considered to be founding father of modern science with study of projectiles, pendulum, gravity. Discovered the thermometer. Asserted that earth revolves around its axis.
Johannes Kepler (1571-1630 AD) Studied theology but he showed that planets move in elliptical motion around the sun (not circular as previously thought by Copernicus).
Thomas Hobbes (1588-1679 AD) Believed that only matter existed, everything could be explained in terms of matter in motion. The whole universe he considered a giant machine. In politics he claimed its the fear of death that forces humans to form societies, and proposed that everyone should agree to hand power to a central authority whose job is to impose law and punish lawbreakers (police state).
Pierre Gassendi (1592-1655 AD) An advocate of the experimental approach to science.
René Descartes (1596-1650 AD) Invented analytic geometry, the graph, looked at humans contradicted themselves and wondered whether there was something that we could know for certain. Famous for his "I think therefore I am".
John Locke (1632-1704 AD) Secularized the notion that there are limits to what humans can apprehend by arguing (in his "Essays concerning Human Understanding") that if we could analyze our own mental faculties and find out what we are capable of and what not we should have discovered the limits of what is knowable by us. He never married.
Benedict Spinoza (1632-1677 AD) He believed that our physical body and the soul is one entity. He believed that for the most part we are not aware of the real causes of our actions. Being deprived of freedom of speech himself he was from the first to proclaim its importance.
Isaac Newton (1642-1727 AD) Accurately analyzed the constituents of light, invented calculus, formulated the gravitational theory, and provided us with accurate account of movements of planets through space.
Gottfried Leibniz (1646-1716 AD) Invented calculus independently of Newton, was offered professorship at 21 which he turned down. Claimed that truths belong in two categories the ones that can be verified with just examining them with logical statements and the ones that need further observation and application of logic.
George Berkeley (1685-1753 AD) A consistent empiricist, believed what exists is our minds and their contents, subjects and their experiences.
Voltaire (1694-1778 AD) Crusader against tyranny, bigotry and cruelty. He subscribed to Locke's idea that the confidence we have in our beliefs needs to relate to the evidence in their support.
David Hume (1711-1776 AD) Believed that humans are a bundle of sensations.
Jean-Jacques Rousseau (1712-1778 AD) He received very little formal education and had espoused to spontaneous feeling against conceptual thinking. He pronounced that civilization was not a good thing as everyone had always assumed.
Denis Diderot (1713-1784 AD) As author and editor of the Encyclopédie he admitted that his aim was to change the common way of thinking.
Adam Smith (1723-1790 AD) Economist and philosopher.
Edmund Burke (1729-1797 AD) His conservatism can be summarized in his belief that the wisdom and experience of many generations is likely to be a more reliable guide to action than any one person's opinion.

Bibliography