Who are Pre-Socratic Philosophers?

The Pre-Socratic period of the Ancient era of philosophy refers to Greek philosophers active before Socrates, or contemporaries of Socrates who expounded on earlier knowledge.

Thales of Miletos (c. 624 – 546 B.C.) Greek
Anaximander (c. 610 – 546 B.C.) Greek
Anaximenes (c. 585 – 525 B.C.) Greek
Pythagoras (c. 570 – 490 B.C.) Greek
Heraclitus (c. 535 – 475 B.C.) Greek
Parmenides of Elea (c. 515 – 450 B.C.) Greek
Anaxagoras (c. 500 – 428 B.C.) Greek
Empedocles (c. 490 – 430 B.C.) Greek
Zeno of Elea (c. 490 – 430 B.C.) Greek
Protagoras (c. 490 – 420 B.C.) Greek
Gorgias (c. 487 – 376 B.C.) Greek
Democritus (c. 460 – 370 B.C.) Greek

Pre-Socratic philosophy is the period of Greek philosophy up to the time of Socrates. It conventionally begins with the work of Thales (sixth century BC). The Pre-Socratic philosophers rejected traditional mythological explanations for the phenomena they saw around them in favor of more rational explanations. They started to ask questions like where did everything come from, and why is there such variety, and how can nature be described mathematically? They tended to look for universal principles to explain the whole of Nature. Although they are arguably more important for the questions they asked than the answers they arrived at, the problems and paradoxes they identified became the basis for later mathematical, scientific and philosophic study.

Important movements of the period include the Milesian School, the Eleatic School, the Ephesian School, Pluralism, Pythagoreanism, Sophism and Atomism.


Democritus (c. 460 – 370 B.C.)


democritusDemocritus (c. 460 – 370 B.C.), sometimes known as the “Laughing Philosopher”, was a Pre-Socratic Greek philosopher from Thrace in northern Greece. Along with his teacher, Leucippus, he was the founder of the Greek philosophical school of Atomism and developed a Materialist account of the natural world.

Although he was a contemporary of Socrates, he usually considered Pre-Socratic in that his philosophy and his approach were more similar to other Pre-Socratic thinkers than to Socrates and Plato.


Democritus was born in Abdera, a town in Thrace in northern Greece, which had originally been settled by Greek colonists from the Ionian city of Teos in present-day Turkey). His date of birth is usually given as 460 B.C., although some authorities argue for upto ten years earlier, and some for a few years later.

His father was very wealthy, and had even received the Persian king Xerxes on his march through Abdera. According to some accounts, Democritus studied astronomyand theology from some of the magi (wise men) Xerxes left in Abdera in gratitude.

On his father’s death, Democritus spent his inheritance on extensive travels to distant countries, to satisfy his thirst for knowledge. He is reputed to have travelled to Persia, Babylon (modern-day Iraq), Asia (as far as India), Ethopia and Egypt(where he lived for five years, being particularly impressed by the Egyptian mathematicians). He also travelled throughout Greece to acquire a knowledge of its culture and meet Greek philosophers (he may have met the physician Hippocrates (c. 460 B.C.) and Socrates, and possibly also Anaxagoras, whom he praises in his own work), and his wealth enabled him to purchase their writings. He was known as one of the most travelled scholars of his time.

On returning to his native land, (now with no means of subsistence), he settledwith his brother Damosis, and occupied himself with natural philosophy and gave public lectures in order to pay his way. His greatest influence was certainly Leucippus, with whom he is credited as co-founding Atomism. In around 440 B.C. or 430 B.C., Leucippus had founded a school at Abdera, and Democritus became his star pupil. There are no existing writings which can be positively attributed to Leucippus, and so it is virtually impossible to identify which ideas were unique to Democritus and which are Leucippus’, or any views about which they disagreed.

From anecdotal evidence, Democritus was known for his disinterestedness, modesty and simplicity, and appeared to live solely for his studies, declining the public honours he was offered. One story has him deliberately blinding himself in order to be less disturbed in his pursuits, although it is more likely that he lost his sight in old age. He was always cheerful and ready to see the comical side of life, and he was affectionately known as the “Laughing Philosopher” (although some writers maintain that he laughed at the foolishness of other people and was also known as “The Mocker”). His knowledge of natural phenomena (such as diagnosing illnesses and predicting the weather) gave him the reputation of being something of a prophet or soothsayer.

It is believed that he died at the age of 90, in about 370 B.C., although some writers have him living to over a hundred years of age.


Diogenes Laertius, the 3rd Century historian of the early Greek philosophers, lists a large number of works by Democritus, covering Ethics, physics, mathematics, music and cosmology, including two works called the “Great World System” and the “Little World System”. However, his works have survived only in secondhand reports, sometimes unreliable or conflicting. Much of the best evidence comes from Aristotle, who was perhaps the chief critic of Atomism, although he nevertheless praised Democritus for arguing from sound considerations, and considered Democritus an important rival in natural philosophy.

Like many other Pre-Socratic philosophies, the Atomism of Leucippus and Democritus was largely a response to the unacceptable claim of Parmenides that change was impossible without something coming from nothing (which is itself impossible), and thus any perceived change or movement was merely illusory.

In the Atomist version, there are multiple unchanging material principles which constantly rearrange themselves in order to effect what we see as changes. These principles are very small, indivisible and indestructible building blocks known as atoms (from the Greek “atomos”, meaning “uncuttable”). All of reality and all the objects in the universe are composed of different arrangements of these eternal atoms and an infinite void, in which they form different combinations and shapes.

There is no room in this theory for the concept of a God, and essentially Atomism is a type of Materialism or Physicalism, as well as being atheistic and deterministic in its outlook. However, Democritus did allow for the existence of the human soul, which he saw as composed of a special kind of spherical atom, in constant motion, and he explained the senses in a similar manner.

In Epistemology, Democritus distinguished two types of knowledge: “bastard”(subjective and insufficient knowledge, obtained by perception through the senses), and “legitimate (genuine knowledge obtained by the processing of this unreliable “bastard” knowledge using inductive reasoning).

In the field of Ethics, Democritus pursued a type of early Hedonism or Epicureanism. He was one of the earliest thinkers to explicit posit a supreme good or goal, which he called cheerfulness or well-being (see the section on Eudaimonism) and identified with the untroubled enjoyment of life. He saw this as achievable through moderation in the pursuit of pleasure, through distinguishing useful pleasures from harmful ones, and through conforming to conventional morality. He is quoted as saying, “The brave man is he who overcomes not only his enemies but his pleasures”.

Democritus was also a pioneer of mathematics and geometry, and produced works entitled “On Numbers”“On Geometrics”“On Tangencies”“On Mapping”and “On Irrationals”, although these works have not survived. We do know that he was among the first to observe that a cone or pyramid has one-third the volume of a cylinder or prism respectively with the same base and height.

He was also the first philosopher we know who realized that the celestial body we call the Milky Way is actually formed from the light of distant stars, even though many later philosophers (including Aristotle) argued against this. He was also among the first to propose that the universe contains many worlds, some of which may be inhabited. He devoted many of the later years of his life to researches into the properties of minerals and plants, although we have no record of any conclusion she may have drawn.

Gorgias (c. 487 – 376 B.C.)


gorgiasGorgias (c. 487 – 376 B.C.) was a Pre-Socratic Greek philosopher, orator and rhetorician from Sicily. Along with Protagoras, he was one of the major figures in the first generation of Sophists.

Both Plato and Aristotle criticized Gorgias severely, labelling him as a mere sophist (in the derogatory sense of “sophistry”) whose primary goal was to make money by appearing wise and clever, and not a true philosopher. However, he was undeniably highly influential and, in bringing his rhetorical innovations from his native Sicily to Athens and Attica, he also contributed to the diffusion of the Attic dialect as the language of literary prose.


Gorgias (pronounced GOR-jas) was born around 487 B.C. (or possibly 483 B.C.) in Leontini, a Greek colony in Sicily. His father was named Charmantides, and he had at least two siblings, a brother named Herodicus and a (unnamed) sister. In his youth, he may have been a pupil of Empedocles, although he would only have been a few years younger. He was familiar with the works of Zeno of Elea and used his paradoxes (especially the so-called “arguments against motion”) in his own work.

He was already about sixty when he was sent in 427 B.C. to Athens by his fellow-citizens at the head of an embassy to ask for Athenian protection against the aggression of the neighbouring Syracusans. On completing his mission, he subsequently settled in Athens, probably due to the enormous popularity of his style of oratory and the profits he could make from his performances and rhetoric classes.

Like other Sophists, he was an itinerant, practising in various cities and giving public exhibitions of his rhetorical skill at the great pan-Hellenic centers of Olympia and Delphi (including inviting questions from the audience and giving impromptu replies), and charged substantial fees for his instruction and performances. His florid, rhyming style seemed to almost hypnotize his audiences, and his powers of persuasion were legendary.

Among his distinguished students in Athens were Isocrates (436 – 338 B.C., one of the greatest and most influential orators of his time), Critias (460 – 403 B.C., a leading member of the so-called Thirty Tyrants of Athens), Alcibiades (c. 450 – 404 B.C., a prominent Athenian statesman, orator and general), Thucydides (c. 460 – 395 B.C., an important historian), Agathon (c. 448 – 400 B.C., a popular tragic poet) and Pericles (c. 495 – 429 B.C., a prominent and influential statesman, orator and general of Athens).

Gorgias is reputed to have lived to be over one hundred years old, before dying at Larissa in Thessaly in about 375 B.C. or 376 B.C. He had accumulated considerable wealth by the time of his death, enough to commission a gold statue of himself for a public temple.


Gorgias transplanted rhetoric from his native Sicily to Athens and Attica, and in the process contributed to the diffusion of the Attic dialect as the language of literary prose. He ushered in rhetorical innovations involving structure and ornamentation and the introduction of paradoxes and paradoxical expression, for which he has been labelled the “father of sophistry”. His rhetorical works (including the “Encomium of Helen”“Defence of Palamedes” and “Epitaphios”) come down to us via a work entitled “Technai”, a manual of rhetorical instruction.

Unlike other Sophists like Protagoras, Gorgias did not profess to teach arete (or virtue), believing that there was no absolute form of virtue but that it was relativeto each situation. He believed that rhetoric was the king of all other sciences, since it was capable of persuading any course of action. Thus, much of the debate over the nature and value of rhetoric, began with Gorgias. Plato (one of Gorgias’ greatest critics) was speaking in direct opposition to Gorgias, when he argued that rhetoric gives the ignorant the power to seem more knowledgeable than an expert to a group, and that Gorgias was merely an orator who entertains his audience with his eloquent words while believing that it is unnecessary to learn the truth about actual matters.

A lost work, “On Nature” or “On Non-Existence”, was one of Gorgias few essays into Metaphysics. It is available to us only in paraphrases from Sextus Empiricus(2nd or 3rd Century A.D.) and others, and it is generally skeptical in outlook, intended both as a refutation and as a parody of the Eleatic School, and particularly of Parmenides. It is usually presented as a three-point argument: 1) nothing exists; 2) even if something exists, nothing can be known about it; and 3) even if something can be known about it, knowledge about it can’t be communicated to others. His point was to prove that it is just as easy to demonstrate that being is one, unchanging and timeless as it is to prove that being has no existence at all.

Protogoras (c. 490 – 420 B.C.)


protagorasProtagoras (c. 490 – 420 B.C.) was a Pre-Socratic Greek philosopher from Thrace in northern Greece, although he made his name as a teacher and advisor in Athens.

Along with his rough contemporary Gorgias, he is considered one of the major figures in the philosophical school of Sophism, and Plato credits him with having invented the role of the professional Sophist or teacher of virtue. He is also sometimes known as the father of Relativism and of Agnosticism.


Protagoras (pronounced pro-TAG-er-as) was born in Abdera, Thrace, in northern Greece. Hints in Plato ‘s dialogue “Protagoras” suggests a date of birth not later than 490 B.C., although exact information is unavailable.

He travelled around Greece for some years earning his living primarily as a teacher and advisor, before settling in Athens. He was well-known there, and became a friend of the prominent Athenian statesman Pericles (c. 495 – 429 B.C.) and other rich and influential Athenians. Pericles apparently invited him to write the constitution for the newly-founded Athenian colony of Thurii in 444 B.C.

Protagoras was probably the first Greek to earn money in higher education and he was notorious for the extremely high fees he charged. His teaching included such general areas as public speaking, criticism of poetry, citizenship and grammar. His teaching methods consisted primarily of lectures, including model orations, analyses of poems, discussions of orthoepeia (the meanings and correct uses of words), and general rules of rhetoric and oratory. His audience consisted mainly of wealthy men from Athens’ social and commercial elites.

Many later legends developed around the life of Protagoras (which are probably false), including stories concerning his having studied with Democritus, his trial for impiety and Atheism, the burning of his books, his flight from Athens to Sicily and his death by drowning.

In Plato ‘s dialogue “Menos”, Protagoras is said to have died at about the age of 70, after 40 years as a practicing Sophist, which would put his death circa 420 B.C.


Protagoras apparently wrote many works, the two of which we have definite knowledge being “Alethia” (“Truth”) and “Peritheon” (“On the Gods”). Unfortunately, none of his works have survived the destruction of the ages. What we know of his works are just a few fragments quoted in the writings of other philosophers, particularly Plato, Aristotle, Diogenes Laërtus and Sextus Empiricus.

Although almost a contemporary of Socrates, Protagoras is considered a Pre-Socratic thinker, as he followed more the Ionian tradition of criticism, rather than the more demonstrative method of Socrates and his followers, Plato and Aristotle. However, he did contribute to philosophy a method of finding a better argument by discarding the less viable one (known as “antilogy”). His claim to be able to “make the worse case the better” was a useful oratorical skill in the extremely litigious quasi-democracy of Athens, but it also had the potential for promoting what most Athenians considered injustice or immorality, and led to an increasing distrust of Sophism.

Although quoted out of context in a later work, his most famous saying is originally from his “Truth”: “Man is the measure of all things: of things which are, that they are, and of things which are not, that they are not”. Another line of Protagoras quoted in Diogenes Laërtus’ “Lives of Eminent Philosophers” is: “There are two sides to every question”. These are both succinct statements of the doctrine of Relativism (that nothing is exclusively good or bad, true or false, and that there is no general or objective truth), and more specifically Moral Relativism. His notion that judgments and knowledge are in some way relative to the person judging or knowing (and indeed that there are as many distinct scales of good and evil as there are individuals in the world), which has come to be known as Ethical Subjectivism, has been very influential and is still widely discussed in contemporary philosophy.

In his lost work “On the Gods”, Protagoras wrote: “Concerning the gods, I have no means of knowing whether they exist or not or of what sort they may be, because of the obscurity of the subject, and the brevity of human life”. This rather bald admission of Agnosticism, was no doubt quite shocking in his day.

Zeno of Elea (c. 490 – 430 B.C.)


zeno_of_eleaZeno of Elea (c. 490 – 430 B.C.) was an important Pre-Socratic Greek philosopher from the Greek colony of Elea in southern Italy. He was a prominent member of the Eleatic School of ancient Greek philosophy, which had been founded by Parmenides, and he subscribed to and defended the Monist beliefs of Parmenides.

Arguably he did not really attempt to add anything positive to the teachings of his master, Parmenides, and he is best known today for his paradoxes of motion. But Aristotle has called him the inventor of the dialectic, and no less a logician and historian than Bertrand Russell has credited him with having laid the foundations of modern Logic.


Zeno was born around 490 B.C. in the Greek colony of Elea in southern Italy. The date is an estimate based on Plato’s report of a visit to Athens by Zeno and his teacher Parmenides when Socrates was “a very young man”, and Zeno being about 25 years younger than Parmenides.

Little is known for certain about Zeno’s life. The 3rd Century A.D. biographer of the ancient Greek philosophers, Diogenes Laërtius, reported that Zeno was the son of Teleutagoras, but was adopted by Parmenides. Plato tells us that Zeno was “tall and fair to look upon” and was reported to have been “beloved” by Parmenides in his youth, so he may have been Parmenides’ eromenos (or adolescent lover, a common tradition of ancient Greece).

He was around forty years old when he accompanied Parmenides to Athens and met the young Socrates. He appears to have lived for at least some time at Athens, and to have explained his doctrines to prominent Athenian statesmen like Pericles (c. 495 – 429 B.C.) and Callias. He was praised as a “universal critic”, skilled in arguing both sides of any question. He devoted all his energies to explaining and developing Parmenides’ philosophical system.

According to some reports, Zeno was arrested and perhaps killed at the hands of a tyrant of Elea. According to the historian Plutarch (c. A.D. 46 – 120), Zeno attempted to kill the tyrant Demylus, and having failed to do so, he bit off his tongue and spit it in the tyrant’s face. However, these details may well be pure inventions, and we can only assume that he died around 430 B.C., although with little or no evidence.


Although several ancient writers refer to the “writings” of Zeno, none of his them have survive intact, and the few fragments of his philosophy we do have mainly come down to us through Aristotle (who was a major detractor of Zeno’s ideas). He did not really add anything positive to the teachings of Parmenides, but devoted himself to refuting the views of his opponents.

Like Parmenides, he taught that the world of sense, with its apparent motion (or change) and plurality (or multiplicity), is merely an illusion. The “true being” behind the illusion is absolutely one and has no plurality (Monism), and furthermore it is static and unchangeable. However, because common sense tells us that there is both motion and plurality (as in the Pythagorean notion of reality), Zeno developed arguments to show that the common sense notion of reality leads to consequences at least as paradoxical as those of Parmenides.underlying intention was to affirm that everything was One (as Monism asserted), that all belief in plurality and change is mistaken, and in particular that motion is nothing but an illusion. To do this he considered what would happen if something was divided into infinitely small amounts, showing that this inevitably resulted in a situation which made no sense, and so must be wrong.

Zeno’s paradoxes were one of the first examples of a method of proof called reductio ad absurdum (or epicheirema in Greek), a kind of dialectical syllogism or proof by contradiction. Although Parmenides himself may actually have been the first to use this style of argument, Zeno became the most famous. He devised arguments against both multiplicity and against motion, although both are really variations of one argument that applies equally to space or time. Essentially, he argued that any quantity of space (or time) must either be composed of ultimate indivisible units or it must be divisible ad infinitum. If it is composed of indivisible units, then these must have magnitude and we are faced with the contradiction of a magnitude which cannot be divided. If, however, it is divisible ad infinitum, then we are faced with the different contradiction of supposing that an infinite number of parts can be added up to make a merely finite sum.

Of Zeno’s original 40 versions of the paradox (of which 8 have come down to us through Aristotle), three in particular have become quite well known:

  • The Paradox of Achilles and the Tortoise: If Achilles allows the tortoise a head start in a race, then by the time Achilles has arrived at the tortoise’s starting point, the tortoise has already run on a shorter distance. By the time Achilles reaches that second point, the tortoise has moved on again, etc, etc. So Achilles can never catch the tortoise.
  • The Arrow Paradox: If an arrow is fired from a bow, then at any moment in time, the arrow either is where it is, or it is where it is not. If it moves where it is, then it must be standing still, and if it moves where it is not, then it cannot be there. Thus, it cannot move at all.
  • The Dichotomy Paradox: Before a moving object can travel a certain distance (e.g. a person crossing a room), it must get halfway there. Before it can get halfway there, it must get a quarter of the way there. Before travelling a quarter, it must travel one-eighth; before an eighth, one-sixteenth; and so on. As this sequence goes on forever, an infinite number of points must be crossed, which is logically impossible in a finite period of time, so the distance will never be covered (the room crossed, etc).

Aristotle vehemently disagreed with Zeno’s ideas, calling them fallacies, and claiming to have disproved them by pointing out that, as the distance decreases, the time needed to cover those distances also decreases, becoming increasingly small. Various other possible solutions have been offered to the paradoxes over the centuries, ranging from Kant, Hume and Hegel, to Newton and Leibniz (who invented mathematical calculus as a method of handling infinite sequences). It is generally held nowadays that the paradox stems from the false assumption that it is impossible to complete an infinite number of discrete tasks in a finite time, but Zeno’s paradoxes have continued to tease and stimulate thinkers, and there is still some debate over whether they have been fully disproved even today.

Empedocles (c. 490 – 430 B.C.)


Empedocles (c. 490 – 430 B.C.) was a Pre-Socratic Greek pempedocleshilosopher, usually considered a member of the poorly-defined Pluralist school in that he was eclectic in his thinking and combined much that had been suggested by others.

He is perhaps best known as the originator of the cosmogenic theory of the four classical elements of the ancient world: earth, air, fire and water, which became the standard dogma for much of the next two thousand years. He is also credited with several prescient ideas in physics which have since proved quite prophetic.

The details of his life have mainly passed into myth, and he has been regarded variously as a materialist physicist, a shamanic magician, a mystical theologian, a gifted healer, a democratic politician, a living god and a fraud and charlatan.


Empedocles (pronounced em-PED-o-clees) was born around 490 B.C. or 492 B.C. at Acragas (Agrigentum in Latin), a Greek colony in Sicily, to a distinguished and aristocratic family. His father, Meto or Meton, seems to have been instrumental in overthrowing Thrasydaeus, the tyrant of Agrigentum in 470 B.C.

Very little is known of Empedocles’ life. He is said to have been very wealthy and was magnanimous in his support of the poor, but severe in persecuting the overbearing conduct of the aristocrats. Some sources mention his travels to southern Italy, the Peloponnese and Athens, and some even further afield, far to the east. He cultivated a regal public persona, with a grave manner and flamboyant clothes.

Despite his airs, he was obviously a popular politician and champion of democracy and equality. He began his political career with the prosecution of two state officials for their arrogant behaviour towards foreign guests (which was seen as a sign of incipient tyrannical tendencies), and is credited with activities against other anti-democratic citizens. He continued his father’s democratic tradition by helping to overthrow the succeeding oligarchic government and instituting a democracy at Acragas. At one point, he was offered effective rule of the city, but he declined.

He was a brilliant orator (Aristotle credited him with the invention of rhetoric itself), and his knowledge of natural phenomena and medical conditions earned him the reputation of marvellous, even magical, powers. Empedocles himself apparently did little to dispel such ideas, and he is reported as claiming seemingly god-like powers (including the ability to revive the dead and to control the winds and rains), and as claiming to be a daimon (a divine, or potentially divine, being).

He was acquainted with the eminent Acragas physicians Acron and Pausanias (the latter was his eromenos or youth lover), with various Pythagoreans (some of the whom had come to Acragas after being attacked in their centre at Croton) and possibly Parmenides and Anaxagoras. The Sophist and rhetorician Gorgias is mentioned as a pupil of Empedocles, although he would only have been a few years younger.

According to Aristotle, Empedocles died at the age of sixty, in 430 B.C. or 432 B.C., although other writers have him living up to the age of 109. The manner of his death is likewise uncertain (reflecting his myth-like status), including his having been “removed” from the earth, or perishing in the volcanic flames of the Mount Etna. Other more prosaic reports include drowning, a fall from a carriage and suicide by hanging.


Empedocles’ work survives only in fragments, but fragments in a far greater number than any of the other Pre-Socratics. His major work, “On Nature” (and possibly parts of a second work, “Purifications”), written in hexameter verse, exists in more than 150 fragments. He was a poet of outstanding ability, and of great influence on later poets such as Lucretius (99 – 55 B.C.)

Empedocles was very familiar with the work of the Eleatic School and the Pythagoreans, and particularly of Parmenides. Like Pythagoras, Empedocles believed in the transmigration of the soul (reincarnation between humans, animals and even plants), and that all living things were on the same spiritual plane, like links in a chain. He therefore urged a vegetarian lifestyle, believing that the bodies of animals are the dwelling places of punished souls. He believed that wise people, who have learned the secret of life, are next to the divine and that their souls, free from the cycle of reincarnations, are able to rest in happiness for eternity.

Like many of the other Pre-Socratics, he found Parmenides’ claim that change is impossible unacceptable, and tried to find the basis of all change. Starting from the assumption (passed down from the Eleatics) that existence cannot pass into non-existence (or vice versa), Empedocles held that change, including what we call coming into existence and death, is only the mixture and separation of the four indestructible and unchangeable elements (or “roots” as he called them): earth, air, fire and water.

He posited two divine powers, Love and Strife, which pervade the universe and act as the moving powers which bring about these mixtures and separations (Loveexplains the attraction of different forms of matter, and Strife accounts for their separation). He further taught that there was a time when the pure elements and the two powers co-existed in a condition of rest and inertness, without mixture and separation, in the form of a sphere (representative of God). The uniting power of Love then predominated in the sphere, and the separating power of Strife guarded the extreme edges of the sphere. Since that time, however, Strife has gained more sway, and the actual world is full of contrasts and oppositions, due to the combined action of both principles.

Empedocles believed that the organic universe sprang from spontaneous aggregations of parts, and only in those rare cases where the parts were found to be adapted to each other, did the complex structures last (arguably a crude anticipation of Charles Darwin’s theory of natural selection). He assumed a cyclical universe, whereby the elements would return to the harmony of the sphere in preparation for the next period of the universe.

Empedocles is also credited with other prescient ideas, such as that light travels with a finite velocity, a form of the law of conservation of energy and a theory of constant proportions in chemical reactions. These theories (arrived at simply through reasoning, rather than through any experimental evidence, of course) had little influence on the development of science, stated as they were within an insufficient theoretical framework, but in retrospect were remarkably prophetic.

Anaxagoras (c. 500 – 428 B.C.)


Anaxagoras (c. 500 – 428 B.C.) was an early Pre-Socratic Greek philosopher from Ionia, although he was one of the first philosophers to move to Athens as a base.

He is sometimes considered to be part of the poorly-defined school of Pluralism, and some of his ideas also influenced the later development of Atomism. Many of his ideas in the physical sciences were quite revolutionary in their day, and quite insightful in retrospect.


Anaxagoras (pronounced an-ax-AG-or-as) was born around 500 B.C. to an aristocratic and landed family in the city of Clazomenae (or Klazomenai) in the Greek colony of Ionia (on the west coast of present-day Turkey). As a young man, he became the first of the major Pre-Socratic philosophers to move to Athens (which was then rapidly becoming the centre of Greek culture), where he remained for about thirty years.

During this time he became a favourite (and possibly a teacher) of the prominent and influential statesman, orator and general Pericles (c. 495 – 429 B.C.), one of the architects of Athens’ primacy during the Golden Age. Although it seems that Anaxagoras and the young Socrates never actually met, one of Socrates’ teachers, Archelaus, studied under Anaxagoras for some time. His work was also known to the major writers of the day, including Sophocles, Euripides, Aeschylus and Aristophanes.

In about 450 B.C., however, Anaxagoras was arrested by Pericles’ political opponents on a charge of contravening the established religion by his teachings on origins of the universe, the first philosopher before Socrates to be brought to trial for impiety. With Pericles’ influence he was released, but he was forced to retire from Athens to exile in Lampsacus in Ionia, where he died around the year 428 B.C.


Anaxagoras wrote at least one book of philosophy, but only fragments of the first part of this have survived in work of Simplicius of Cilicia in the 6th Century A.D.

He is best known for his cosmological theory of the origins and structure of the universe. He maintained that the original state of the cosmos was a thorough mixture of all its ingredients, although this mixture was not entirely uniform, and some ingredients are present in higher concentrations than others and varied from place to place. At some point in time, this primordial mixture was set in motion by the action of nous (“mind”), and the whirling motion shifted and separated out the ingredients, ultimately producing the cosmos of separate material objects (with differential properties) that we perceive today.

For Anaxagoras, this was a purely mechanistic and naturalistic process, with no need for gods or any theological repercussions. However, he did not elucidate on the precise nature of Mind, which he appears to consider material, but distinguished from the rest of matter in that it is finer, purer and able to act freely. It is also presentin some way in everything, a kind of Dualism.

Anaxagoras developed his metaphysical theories from his cosmological theory. He accepted the ideas of Parmenides and the Eleatics that the senses cannot be trusted and that any apparent change is merely a rearrangement of the unchanging, timeless and indestructible ingredients of the universe. Not only then is it impossible for things to come into being (or to cease to be), he also held that there is a share of everything in everything, and that the original ingredients of the cosmos are effectively omnipresent (e.g. he argued that the food an animal eats turns into bone, hair, flesh, etc, so it must already contain all of those constituents within it). He denied that there is any limit to the smallness or largeness of the particles of the original cosmic ingredients, so that infinitesimally small fragments of all other ingredients can still be present within an object which appears to consist entirely of just one material (presaging to some extent the ideas of Atomism).

In the physical sciences, Anaxagoras was the first to give the correct explanation of eclipses, and was both famous and notorious for his scientific theories, including his claims that the sun is a mass of red-hot metal, that the moon is earthy, and that the stars are fiery stones.

Parmenides of Elea (c. 515 – 450 B.C.)


Parmenides of Elea (c. 515 – 450 B.C.) was an early Pre-Socratic Greek philosopher and founder and chief representative of the Eleatic School of ancient Greek philosophy.

He is one of the most significant and influential (as well as the most difficult and obscure) of the Pre-Socratic philosophers, and he is sometimes referred to as the father of Metaphysics. He particularly influenced Plato (and, through him, the whole of Western Philosophy), who always spoke of him with veneration. Perhaps his greatest contribution to philosophy was his method of reasoned proof for assertions.

In denying the reality (or even the possibility) of change as part of his Monist philosophy, Parmenides presented a turning point in the history of Western Philosophy, and sparked a philosophical challenge that determined the course of enquiries of subsequent philosophers such as Empedocles, Anaxagoras and Democritus, and an intellectual revolution that still echoes today.


Parmenides (pronounced par-MEN-i-dees) was born in the Greek colony of Elea (southern Italy). His birth date is uncertain and the evidence of Diogenes Laërtius and Plato is contradictory, but it is likely that he was born some time between 540 and 510 B.C., with 515 B.C. as a “best guess”.

He is said to have been a student of Xenophanes of Colophon (570 – 480 B.C.), and what we know of Xenophanes’ philosophy seems to be an influence on Parmenides. Diogenes Laërtius also describes Parmenides as a disciple of the Pythagorean philosopher Aminias, although there are few Pythagorean elements in his thought.

He was the founder of the School of Elea, which also included Melissus of Samos and the young Zeno of Elea (who was about 25 years younger than Parmenides and may also have been his eromenos or adolescent lover, a common tradition of ancient Greece).

He was held in high esteem by his fellow-citizens for his excellent legislation, to which they ascribed the prosperity and wealth of the town, and it is suggested that he had written the laws of the city, which had been founded shortly before 535 B.C. He was also admired for his exemplary life (a “Parmenidean life” was proverbialamong the Greeks).

Little more is known of his biography than that he stopped at Athens on a journey in his sixty-fifth year (around the middle of the 5th Century B.C.) and there became acquainted with the youthful Socrates (SocratesPlato and Aristotle were all strongly inspired by Parmenides). His death is assumed to have taken place around 440 or 450 B.C.


Parmenides’ only known work, a poem written in hexameter verse around 475 B.C.and entitled “On Nature”, has only survived in fragmentary form, with approximately 150 of the original 3,000 lines of text remaining today. It is divided into two main sections, describing the two ways or two views of reality, “The Way of Truth” (which accounts for most of the surviving lines) and “The Way of Appearance/Opinion”, along with an introduction. Parmenides argued in favour of the Way of Truth and against The Way of Appearance.

In the poem, Parmenides argued that the every-day perception of the reality of the physical world is mistaken, and that the reality of the world is “the One”, an unchanging, ungenerated, indestructible whole. Likewise, the phenomena of movement and change are simply appearances of the real static, eternal reality. He further asserted that the truth cannot be known through sensory perception, only through pure reason (“Logos”).

Parmenides set out the heart of his case in a worldview that (even by the standards of philosophy) is, according to Aristotle, “near to madness”. He argued as follows: “What-is-not” does not exist. Since anything that comes into being must arise out of “what-is-not”, objects cannot come into being. Likewise, they cannot pass away, because in order to do so they would have to enter the realm of “what-is-not”. Since it does not exist, “what-is-not” cannot be the womb of generation, or the tomb of that which perishes. The “no-longer” and the “not-yet” are therefore variants of “what-is-not”, and so the past and future do not exist either. Change, then, is impossible.

Equally, his argument continued, multiplicity is unreal, because the empty spacenecessary to separate one object from another would be another example of “what-is-not”. And since things cannot be anything to a greater or lesser degree (which would require “what-is” to be mixed with the diluting effect of “what-is-not”), the universe must be homogeneous, a single, undifferentiated, unchanging unity. Also, it must be finite and spherical, for it cannot be in one direction any more than in another (and the sphere is the only figure of which this can be said).

Thus, by a strictly deductive argument, Parmenides asserted that change is impossible, and that coming-into-existence or ceasing-to-exist are likewise impossible, so that everything that exists is permanent, ungenerated, indestructible and unchanging. His argument refutes all accounts of the origin of the world, and represents an early type of Monism.

Parmenides therefore made the ontological argument against nothingness, essentially denying the possible existence of a void, which led Leucippus and Democritus to propose their theory of Atomism (that everything in the universe is either atoms or voids) specifically to contradict his argument.

Heraclitus of Ephesus (c. 535 – 475 B.C.)


Heraclitus of Ephesus (c. 535 – 475 B.C.) was a Pre-Socratic Greek philosopher from Ephesus, on the Ionian coast of modern-day Turkey. He is sometimes mentioned in connection with the Ephesian School of philosophy, although he was really the only prominent member of that school (which, along with the Milesian School, is often considered part of the Ionian School).

He was perhaps the first Western philosopher to go beyond physical theory in search of metaphysical foundations and moral applications, and some consider him, along with Parmenides, the most significant of the Pre-Socratic philosophers. His idea of a universe in constant change but with an underlying order or reason (which he called Logos) forms the essential foundation of the European worldview.

Many subsequent philosophers, from Plato to Aristotle, from the Stoics to the Church Fathers, from Georg Hegel to Alfred North Whitehead, have claimed to have been influenced by the ideas of Heraclitus.



According to the “Lives and Opinions of Eminent Philosophers” of Diogenes Laërtius (the 3rd Century historian of the ancient Greek philsophers), Heraclitus flourished in the 69th Olympiad (which would be 504 – 501 B.C.), but the dates of his birth and death are just guesswork based on that. So, all we can say it is it is likely that he was born around 535 B.C. We do know that he was born to an aristocratic family in Ephesus, an important city on the Ionian coast of modern-day Turkey.

His father was named either Bloson or Herakon, and was a powerful figure in the city. But, according to Diogenes Laërtius, Heraclitus abdicated the kingship(probably just an honorific title) in favour of his brother, and had no interest in politics or power. As a youth, he was a prodigious intellect, and he claimed to have taught himself everything he knew by a process of self-questioning. Some sources also say that he was a pupil of Xenophanes (570 – 480 B.C.), but that is disputed.

He was sometimes known as “the Obscure” (or “the Dark”) for the deliberate difficulty and unclearness of his teachings. He was also known as the “Weeping Philosopher”, and it is speculated that he was prone to melancholia or depression, which prevented him from finishing some of his works. There is no record of his having travelled, even as far as the nearby learning centre of Miletus, although he seems to have been familiar with the ideas of the Milesian School.

He was apparently something of a misanthrope and a loner, and he cultivated an aristocratic disdain for the masses and favoured the rule of a few wise men. He was not afraid to scorn and denigrate (in no uncertain terms, and in a characteristic shrill voice) almost everyone from the Ephesians to the Athenians to the Persian leader, Darius. He believed that the poet Hesiod and Pythagoras “lacked understanding”, and claimed that Homer and Archilochus deserved to be beaten. Diogenes Laërtius reported that, later in life, he wandered the mountains, eating only grass and herbs.

His years of wandering in the wilderness, resulted in an oedema (dropsy) and impairment of vision. After 24 hours of his own idiosyncratic treatment (a liniment of cow manure and baking in the sun), he died and was interred in the marketplace of Ephesus.


Heraclitus is recorded as having written a single book, “On Nature”, divided into three discourses, one on the universe, another on politics and a third on theology. The book was deposited or stored in the great Temple of Artemis in Ephesus (as were many other treasures and books of the time) and made available to visitors for several centuries after Heraclitus’ death. However, his writings only survive today in fragments quoted by other later authors.

In his work, he used puns, paradoxes, antitheses, parallels and various rhetorical and literary devices to construct expressions that have meanings beyond the obvious. The reader must therefore solve verbal puzzles (he was also nicknamed “The Riddler”), and, by so doing, learn to read the signs of the world. In fact, he deliberately made his philosophical work obscure, so that none but the already competent would be able to understand it.

Unlike many of the other Pre-Socratic philosophers, Heraclitus believed that the world is not to be identified with any particular substance, but rather consists of a law-like interchange of elements, an ongoing process governed by a law of perpetual change, or Logos, which he symbolized by fire. According to Heraclitus, fire provides a kind of standard of value for other stuffs, but it is not identical to them, and is not the unique source of all things, because all stuffs are equivalentand one thing is transformed into another in a cycle of changes.

According to Heraclitus, the world is in an eternal state of “becoming”, and all changes arise from the dynamic and cyclic interplay of opposites. Opposites are necessary for life, he believed, but they are unified in a system of balanced exchanges, with pairs of opposites making up a unity. Thus, one road carries some travellers out of a city, while it brings others back in; the way up is also the way down; earth changes to fire and fire changes to earth, etc. In this, he posits an equal and opposite reaction to every change and, in his theory of the equivalence of matter, a primitive law of conservation.

The most famous aphorism often attributed to Heraclitus, that “everything is in a state of flux”, probably comes in reality from the much later Neo-Platonist Simplicius of Cilicia (490 – 560 A.D.), although other similar quotes are attributable to him, and it remains a pithy summary of his views on the recurrent Pre-Socratic problem of change. Similarly, he is often quoted as saying that one cannot step twice into the same river, although this is based on a simplistic paraphrasing of Plato’s. What he was really suggesting is that rivers can stay the same over time even though (or indeed because) the waters in it change.

Thus, contrary to the contentions of both Plato and Aristotle, Heraclitus did not hold the extreme (and logically incoherent) views that everything is constantly changing, that opposite things are identical, and that everything is and is notat the same time. But he did recognize a lawlike flux of elements, with fire changing into water and then into earth, and earth changing into water and then into fire. While parts of the world are being consumed by fire at any given time, the whole remains. Heraclitus does, to be sure, make paradoxical statements, but his views are no more self-contradictory than some of the claims of Socrates.

Heraclitus saw the theory of nature and the human condition as intimately connected, and he was one of the first philosophers to make human values a central concern. He viewed the soul as fiery in nature, generated out of other substances, just as fire is, but limitless in dimension. Thus, drunkenness, for example, damages the soul by causing it to be moist, while a virtuous life keeps the soul dry and intelligent.

He further believed that the laws of a city-state are an important principle of order, and that they derive their force from a divine law. In this way, he introduced the notion of a law of nature that informs human society as well as nature, and this idea of an inherent moral law greatly influenced the later Stoicism movement.

He saw Divinity as present in the world, but not as a conventional anthropomorphic being such as the Greeks worshipped. For Heraclitus, the world itself either is God, or is a manifestation of the activity of God, which is somehow to be identified with the underlying order of things.


Pythagoras (c. 570 – 490 B.C.)


Pythagoras of Samos (c. 570 – 490 B.C.) was an early Greek Pre-Socratic philosopher and mathematician from the Greek island of Samos.

He was the founder of the influential philosophical and religious movement or cult called Pythagoreanism, and he was probably the first man to actually call himself a philosopher (or lover of wisdom). Pythagoras (or in a broader sense the Pythagoreans), allegedly exercised an important influence on the work of Plato.

As a mathematician, he is known as the “father of numbers” or as the first pure mathematician, and is best known for his Pythagorean Theorem on the relation between the sides of a right triangle, the concept of square numbers and square roots, and the discovery of the golden ratio.

Unfortunately, little is known for sure about him, (none of his original writings have survived, and his followers usually published their own works in his name) and he remains something of a mysterious figure. His secret society or brotherhood had a great effect on later esoteric traditions such as Rosicrucianism and Freemasonry.


Pythagoras was born on the Greek island of Samos, in the eastern Aegean Sea off the coast of Turkey, some time between 580 and 572 B.C. His father was Mnesarchus, a Phoenician merchant from Tyre; his mother was Pythais, a native of Samos. He spent his early years in Samos, but also travelled widely with his father.

According to some reports, as a young man he met Thales , who was impressed with his abilities and advised him to head to Memphis in Egypt and study mathematics and astronomy with the priests there, which he soon had the opportunity of. He also travelled to study at the temples of Tyre and Byblos in Phoenicia, as well as in Babylon. At some point he was also a student of Pherecydes of Syros and of Anaximander (who himself had been a student of Thales).While still quite a young man, he left his native city for Croton in southern Italy in order to escape the tyrannical government of Polycrates, the Tyrant of Samos (or possibly to escape political problems related to an Egyptian-style school called the “semicircle”which he had founded on Samos).

In Croton, Pythagoras established a secret religious society very similar to (and possibly influenced by) the earlier Orphic cult, in an attempt to reform the cultural life of Croton. He formed an elite circle of followers around himself, called Pythagoreans or the Mathematikoi (“learners”), subject to very strict rules of conduct, owning no personal possessions and assuming a largely vegetarian diet. They followed a structured life of religious teaching, common meals, exercise, music, poetry recitations, reading and philosophical study (very similar to later monastic life). The school (unusually for the time) was open to both male and female students uniformly (women were held to be different from men, but not necessarily inferior). The Mathematikoi extended and developed the more mathematical and scientific work Pythagoras began.

Other students, who lived in neighbouring areas, were also permitted to attend some of Pythagoras’ lectures, although they were not taught the inner secrets of the cult. They were known as the Akousmatikoi (“listeners”), and they focused on the more religious and ritualistic aspects of Pythagoras’ teachings (and were permitted to eat meat and own personal belongings).

Among his more prominent students were the philosopher Empedocles, Brontinus (who may have been Pythagoras’ successor as head of the school), Philolaus (c. 480 – 385 B.C., who has been credited with originating the theory that the earth was not the center of the universe), Lysis of Taras (who is sometimes credited with many of the works usually attributed to Pythagoras himself), Cercops(an Orphic poet), Hippasus of Metapontum (who is sometimes attributed with the discovery of irrational numbers), Zamolxis (who later amassed great wealth and a cult following as a god among the Thracian Dacians) and Theano (born c. 546 B.C., a mathematician, student, and possibly wife or daughter, of Pythagoras).

Towards the end of his life, Pythagoras fled to Metapontum (further north in the Gulf of Tarentum) because of a plot against him and his followers by a noble of Croton named Cylon. He died in Metapontum from unknown causes some time between 500 and 490 B.C., between 80 and 90 years old.



Because of the secretive nature of his school and the custom of its students to attribute everything to Pythagoras himself, it is difficult today to determine who actually did which work. To further confuse matters, some forgeries under his name (a few of which still exist) circulated in antiquity. Some of his biographers clearly aimed to present him as a god-like figure, and he became the subject of elaborate legends surrounding his historical persona.

The school that Pythagoras established at Croton was in some ways more of a secret brotherhood or monastery. It was based on his religious teachings and was highly concerned with the morality of society. Members were required to live ethically, love one another, share political beliefs, practice pacifism, and devote themselves to the mathematics of nature. They also abstained from meat, abjured personal property and observed a rule of silence (called “echemythia”), the breaking of which was punishable by death, based on the belief that if someone was in any doubt as to what to say, they should remain silent.

Pythagoras saw his religious and scientific views as inseparably interconnected. He believed in the theory of metempsychosis or the transmigration of the soul and its reincarnation again and again after death into the bodies of humans, animals or vegetables until it became moral (a belief he may have learned from his one-time teacher Pherecydes of Syros, who is usually credited as the first Greek to teach the transmigration of souls). He was one of the first to propose that the thought processes and the soul were located in the brain and not the heart.

Another of Pythagoras’ central beliefs was that the essence of being (and the stability of all things that create the universe) can be found in the form of numbers, and that it can be encountered through the study of mathematics. For instance, he believed that things like health relied on a stable proportion of elements, with too much or too little of one thing causing an imbalance that makes a person unhealthy.

In mathematics, Pythagoras is commonly given credit for discovering what is now know as the Pythagorean Theorem (or Pythagoras’ Theorem), a theorem in geometry that states that, in a right-angled triangle, the square of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides. Although this had been known and utilized previously by the Babylonians and Indians, he (or perhaps one of his students) is thought to have constructed the first proof.

He believed that the number system (and therefore the universe system) was based on the sum of the numbers one to four (i.e. ten), and that odd numbers were masculine and even numbers were feminine. He discovered the theory of mathematical proportions, constructed from three to five geometrical solids, and also discovered square numbers and square roots. The discovery of the golden ratio (referring to the ratio of two quantities such that the sum of those quantities and the larger one is the same as the ratio between the larger one and the smaller, approximately 1.618) is also usually attributed to Pythagoras, or possibly to his student, Theano.

He was one of the first to think that the Earth was round, that all planets have an axis, and that all the planets travel around one central point (which he originally identified as the Earth, but later renounced it for the idea that the planets revolve around a central “fire”, although he never identified it as the Sun). He also believed that the Moon was another planet that he called a “counter-Earth”.

Pythagoras was also very interested in music, and wanted to improve the music of his day, which he believed was not harmonious enough and was too hectic. According to legend, he discovered that musical notes could be translated into mathematical equations by listening to blacksmiths at work. “Pythagorean tuning” is a system of musical tuning in which the frequency relationships of all intervals are based on the ratio 3:2 (a stack of perfect fifths), a system which has been documented as long ago as 3500 B.C. in Babylonian texts, but which is nevertheless often attributed to Pythagoras. He also believed in the “musica universalis” (or the “harmony of the spheres”), the idea that the planets and stars moved according to mathematical equations, which corresponded to musical notes and thus produced a kind of symphony.