Socrates, Aristotle and Plato are by far the most famous Greek philosophers commonly associated with the Greek classical period. Yet, these masterminds owe a lot to a series of thinkers that lived during the 6th and 5th centuries BCE known as Presocratics.
The Presocratics were the first philosophers in the western canon and produced a great variety of different theories that tried to explain the nature of the universe. The foundations of science and philosophy were laid with these early thinkers.
In this article, we will explore the 13 most important Presocratic philosophers of ancient Greece.
The Eve Of The Greek Philosophers
In the 6th and 5th centuries, the Greek-speaking world witnessed the rise of a diverse movement of thinkers starting with Thales, the first philosopher in the Western tradition.
These philosophers formulated new theories about the way nature and human societies work. From the natural philosophy of the Milesians to the mysticism of Pythagoras, and from the Logos of Heraclitus to the atomic theory of Leucippus and Democritus, this was a period of marvels.
Philosophers at this point in time were not only practicing philosophy in the modern sense. They were also astronomers, mathematicians, physicists, social scientists, and more. Besides, these were philosophers in the literal sense of the word as “friends of wisdom.”
Greek Philosophers Before Socrates: The Presocratics
The term Presocratics was coined in the 18th century CE by scholars interested in Greek philosophy. However, it was popularized by Herman Diels in the 19th century. Diels used this term to underline the difference between these thinkers that he believed were interested in natural phenomena and Socrates who was interested in moral philosophy.
Nevertheless, the presocratics were also interested in moral and political problems. Moreover, although presocratics literally means “before Socrates,” many of the thinkers classified as Presocratics were contemporaries of Socrates.
One thing actually linking all the Presocratics is that their work is lost. In contrast to Plato and Aristotle who were lucky enough to have large parts of their work preserved, the Presocratics are now accessible only through fragments of their work surviving in the work of later authors.
The rest of this article is a list of 13 presocratic philosophers with information about their lives and philosophical theories.
All quotes in the form of fragments are taken from Kathleen Freeman’s Ancilla to the Pre-Socratic Philosophers.
1. Thales Of Miletus (c.625-c.546 BCE)
Like his fellow thinkers from Miletus (Anaximander and Anaximenes), Thales was interested in natural philosophy. Aristotle considered Thales to be the first philosopher in the Greek tradition and consequently of the western canon. The Milesian was additionally included amongst the seven sages of Greece.
Thales came up with a system where water was the origin of all matter. In addition, he famously predicted the solar eclipse of 585 BCE and introduced geometry from Egypt to Greece, as well as other inventions. Thales calculated the height of Egypt’s pyramids and the distance of ships from the shore using geometry. He is also attributed with developing the ‘Thales Theorem.’
Like most of the presocratics, and especially the ones from Miletus, Thales was not just a philosopher but an individual seeking knowledge in every corner he could get it. He was a mathematician, astronomer, engineer, and so much more.
2. Anaximander Of Miletus (c.610-c.546 BCE)
Also active in the city of Miletus was Anaximander, a student of Thales. Anaximander was one of the first philosophers to write a book. Like Thales, he was also interested in many different areas. He is attributed with the invention of the gnomon, although that is highly unlikely.
Anaximander was also thought to be the first to draw a map of the known world. He disagreed with his teacher regarding the basic substance of the universe. While Thales believed that everything came out of the water, Anaximander attributed everything to the Apeiron (literally translates as “the infinite”). This was an abstract entity that gave birth to everything and was the place where all things returned.
Anaximander was also the first to use the term arche (beginning) in a philosophical context. Additionally, he speculated that animals and humans evolved out of other animals that live in the water and believed in the existence of multiple worlds.
3. Anaximenes Of Miletus (c.586-c.526 BCE)
“Air is near to the incorporeal; and since we come into being by an efflux from this (air), it is bound to be both non-limited and rich so that it never fails.”
Anaximenes was the third Milesian amongst the Greek philosophers before Socrates. He was a student of Anaximander and was also a monist. Where Thales saw water and Anaximander the Apeiron, Anaximenes saw air, which he thought was the arche (beginning) of all things.
Heraclitus and Xenophanes
4. Heraclitus Of Ephesus (c.535-c.475 BCE)
Heraclitus was born in Ephesus of Asia Minor where he produced a philosophy of change. He believed that the world is made of fire and is always moving.
For Heraclitus, nothing ever remains the same, a philosophy which is summed up in the phrase Panta Rhei (everything flows). His most famous quotes are about this idea of a universe in constant change and movement.
“You cannot step twice into the same rivers; for fresh waters are ever flowing in upon you.”
“We step and do not step into the same rivers; we are and are not.”
Another important part of his philosophy is his idea of the unity of the opposites. This meant that for Heraclitus, opposites like good and bad, being and non-being, night and day, up and down, were in fact one. Not one as indiscernible but as in the way that a coin has two sides.
He is also the first Greek philosopher to talk about the Logos, a term that became extremely popular in the next centuries and continues to be one of the most central terms for philosophers even today.
Heraclitus is said to have left only one work called On Nature and was particularly influential. In later centuries he became known as the “weeping philosopher” because many of his fragments appeared pessimistic to scholars. He was also called the “Obscure philosopher” because of his cryptic sayings. Plato, Nietzsche, Hegel, Heidegger, and even communist leader Lenin were fans of the Ephesian philosopher.
5. Xenophanes Of Colophon (c.570-c.478 BCE)
Just like all of the Greeks philosophers before Socrates, Xenophanes was not your typical philosopher. He was a poet and theologist who spoke firmly against the idea of polytheism. Xenophanes criticized the theological views of Homer and Hesiod who painted an immoral image of gods who committed theft, adultery and more. He also believed that the gods were not like humans and that there was only one non-anthropomorphic deity.
Xenophanes was also amongst the first to talk of the limits of human knowledge. He spoke of the impossibility to understand the truth about the gods and insisted that knowledge is relative. As a result, he was one of the first relativists in history:
“If God had not created yellow honey, they would say that figs were far sweeter.”
“Aethiopians have gods with snub noses and black hair, Thracians have gods with grey eyes and red hair.”
“But if oxen (and horses) and lions had hands or could draw with hands and create works of art like those made by men, horses would draw pictures of gods like horses, and oxen of gods like oxen, and they would make the bodies (of their gods) in accordance with the form that each species itself possesses.”
The Pythagorean Tradition
6. Pythagoras Of Samos (c.575-c.490 BCE)
The philosopher Pythagoras was born on the Greek island of Samos. At c. 530 BCE he moved to Croton of South Italy to found his school. Pythagoras is one of the most interesting presocratics existing somewhere between myth and history.
It really is difficult to talk about Pythagoras. His school in Croton was a secret society with teachings accessible only to those initiated. As a result, the beliefs of the society’s members are not really clear.
However, we do know that Pythagoras’s school taught an ascetic way of life that demanded dietary restrictions and promoted a spirituality that idolized numbers and math, called numerology.
In many ways, Pythagoras was more like a prophet than a philosopher, and his school more like a monastery. The ascetic life, the communal lifestyle, the obsession with the divine meaning of numbers, and the miracles attributed to Pythagoras are enough proof of that. Aristotle tells us that the people in Croton called Pythagoras “Hyperborean Apollo” and that once in Olympia he revealed his thigh which was made out of gold.
A central idea in Pythagorean thought was the belief in metempsychosis, the reincarnation of the soul after death.
Pythagoras is also attributed with a series of scientific achievements that could or could not actually be his, like the Pythagorean theorem, the Pythagorean tuning in music, the theory of Proportions, the spherical shape of the earth, and more.
Socrates, Plato, Aristotle, the Neoplatonists, and many presocratic thinkers were heavily influenced by Pythagoras and his tradition.
The Eleatics: Greek Philosophers Against Movement
7. Parmenides Of Elea (end of 6th-beginning of 5th century BCE)
“…the one that it is, and it is not possible for it not to be, is the way of credibility, for it follows Truth; the other, that it is not, and that it is bound not to be: this I tell you is a path that cannot be explored; for you could neither recognise that which is not, nor express it.”
Parmenides was the founder of the Eleatic school and one of the most influential early Greek philosophers. Plato wrote a dialogue called Parmenides where it is stated that a young Socrates met Parmenides when he was around 65 years in Athens.
Parmenides wrote only one book and only a poem from this work is preserved. This contains extremely difficult and abstract philosophical ideas regarding the nature of being. These ideas are in complete opposition to the ones found in the work of the Ionian philosophers. Furthermore, it seems that the Greek philosopher had serious doubts regarding the possibility of obtaining the truth about the world using our senses.
In many ways, Parmenides is the complete opposite of Heraclitus. Where Heraclitus talked of change and movement, Parmenides insisted on an unchanging, stable universe. While Heraclitus emphasized that the world is a Becoming, Parmenides held that what exists is part of the one that is timeless, uniform, unchanging, immovable, indestructible, and perfect.
8. Zeno Of Elea (c.495-c.430 BCE)
“That which moves, moves neither in the place in which it is, nor in that in which it is not.”
Zeno was a student of Parmenides and his successor as the head of the Eleatic school. According to Plato’s dialogue Parmenides, Zeno met young Socrates when he visited Athens with Parmenides to present his book.
In antiquity, Zeno became famous for his paradoxes that sought to prove that all motion and change were illusions. With these paradoxes, Zeno was trying to prove the ontological theories of his teacher that the world was uniform, unchanging and immovable.
Aristotle discussed these paradoxes in detail offering entertaining insights into Zeno’s thought. One of the paradoxes is the following:
“The first (paradox) asserts the non-existence of motion on the ground that that which is in locomotion must arrive at the half-way stage before it arrives at the goal.” Aristotle
In a few words, Zeno claims that to cover a distance someone has to cover half of the distance first. But since we can keep dividing distance in half ad infinitum, it is not possible to move from any point to another.
9. Empedocles Of Acragas (c.494-c.434 BCE)
The presocratic philosopher with the most bizarre stories surrounding his death is without a doubt Empedocles of Acragas. In one story he disappeared into the heavens at night and in another, he leaped into the volcanic crater of Mount Etna. Most probably though, none of these stories is true.
Inspired by the Pythagoreans, Empedocles is an almost messianic figure. In one story, it is said that he resurrected a woman that had stopped breathing. Of course, these stories tell more about popular imagination than Empedocles himself.
He was influenced by the philosophy of Parmenides and was the last of Greek philosophers to express his ideas in verse. Empedocles denounced animal sacrifices and advocated vegetarianism alongside a theory of reincarnation (metensarcosis).
He also taught that there are four elements; fire, air, water, and earth. Everything in existence is a transformation of these four elements. Two powers, Strife and Love are responsible for the different ratios of each of these elements in things. Strife makes the elements withdraw to themselves while Love makes them unite.
10. Anaxagoras Of Clazomenae (c.500-c.428 BCE)
“The Greeks have an incorrect belief on Coming into Being and Passing Away. No Thing comes into being or passes away, but it is mixed together or separated from existing Things. Thus they would be correct if they called coming into being ‘mixing’, and passing away ‘separation-off’.”
Anaxagoras wrote only one book and he was mainly influenced by the theories of Parmenides. However, his own theory was a reaction to the Eleatic monism.
According to Anaxagoras, in the beginning, everything existed in infinitely small fragments and in infinite numbers in such a small place and in such close proximity that they were almost indiscernible. The re-arrangement of these fragments was orchestrated by the cosmic mind which he called Nous.
Anaxagoras spend a good part of his life teaching in Athens. Like Socrates, he was one of the Greek philosophers to undergo a trial for their ideas. The Athenians blamed him for impiety probably because of his views that rejected the existence of lunar and solar deities. Pericles, the Athenian politician, defended Anaxagoras in his trial as the two of them were friends. In the end, Pericles advised Anaxagoras to leave Athens, and the philosopher left for Lampsacus, where he died.
Greek Philosophers Of The Atomic Theory
11. Leucippus Of Miletus (in his prime c.430 BCE)
Today when we hear of the atomic theory, our mind directly goes to nuclear weapons and power plants. However, the atomic theory is much, much older. In fact, it is as old as Leucippus, the first of a series of Greek philosophers called the atomists.
“Nothing happens at random; everything happens out of reason and by necessity.”
Leucippus claimed that everything is made of tiny indivisible things called atoms, which literally translates as “that which cannot be cut”. A core point in his theory is that for movement to be possible, a vacuum needs to exist. In a few words, for being to exist, there must be non-being.
In many ways, Leucippus continued the naturalistic Ionian philosophy of Thales, Anaximander, Anaximenes and Heraclitus. Furthermore, he was the first to claim that things are the way they are because of their nature.
Leucippus established a philosophical school at Abdera and according to a story, he founded the city of Metapontum.
12. Democritus of Abdera (c.460-c.370 BCE)
“(I would) rather discover one cause than gain the kingdom of Persia.”
“atoms and Void (alone) exist in reality”.
Born in Abdera of Thrace, Democritus was a wealthy citizen who traveled a lot during his life. Very commonly he is listed together with his teacher Leucippus making it difficult to tell their views apart. He wrote 73 books and led a life avoiding active engagement in politics, though he did give public lectures.
Democritus visited India, Egypt, Ethiopia and Persia where it is said that he studied under Ostane, a magus in the court of King Xerxes. He is also said to have been initiated into Pythagoreanism at some point in his life and have briefly studied next to Anaxagoras.
Like his teacher, Democritus insisted that matter is made of indivisible parts called atoms that interact mechanically with each other. He also believed that there were atoms of different sizes and shapes. For example, he held that air atoms were different from iron atoms and that these differences dictated their interaction.
Democritus also valued the intellect as a valid source of knowledge and cautioned against any truth obtained through the senses. We know that he made some contributions in the fields of aesthetics, mathematics, biology, anthropology and other sciences. Like many Greek philosophers, he also believed in the existence of multiple worlds.
Democritus became known in antiquity as the “laughing philosopher” as opposed to Heraclitus, the “weeping philosopher.” That was because of his emphasis on the value of cheerfulness.
Although his political and ethical thinking is not reconstructable, we know that Democritus advocated in favor of a life of moderation where a certain degree of hedonism was acceptable.
Sophists: The Greek Philosophers That Socrates Despised
13. Protagoras Of Abdera (c.490-c.420 BCE)
The sophists were a group of teachers experienced in philosophy who, according to Plato, mainly supported the view that there is no objective truth. Protagoras was one of the most important representers of this movement and a student of Democritus.
In the dialogue of Plato called Protagoras, the Greek philosopher debates Socrates over the nature of virtue. Although Plato was not fond of the sophists in general, he presents Protagoras as a respected thinker.
Protagoras believed that for everything, there were always two arguments of equal strength. As a result, he was seriously doubting the possibility of obtaining an objective truth. For this reason, Protagoras is considered one of the most important thinkers in the history of relativism.
“Of all things the measure is Man, of the things that are, that they are, and of the things that are not, that they are not.”
In addition, Protagoras took a seemingly agnostic stance on the issue of the existence of gods:
“About the gods, I am not able to know whether they exist or do not exist, nor what they are like in form; for the factors preventing knowledge are many: the obscurity of the subject, and the shortness of human life.”
This agnosticism brought Protagoras to a difficult position as the Athenians banished him from the city and burned all copies of his books.
Although he respected Protagoras, Socrates oftentimes spoke against the sophists and their axiom that there is no single truth.