Primers › Philosophy

The Presocratics

Western philosophy usually gets started with a group of Greek thinkers who lived between roughly 600 and 400 BCE (“before the common era,” the same years as BC), before and alongside Socrates. None of their books survive whole. We know them from fragments, short passages that later writers quoted, and from summaries by people like Aristotle, so scholars still argue over what some of them meant [1]. Many of the colorful stories about their lives were made up later, too [2], [3]. This primer follows the first two episodes of the Philosophize This! podcast [4], [5] and checks them against two scholarly encyclopedias, flagging the places where the popular version and the scholarship disagree.

Two questions run through all of them:

1. What is everything made of? Greek has a word for the basic stuff or starting point of things, archē, which means both “origin” and “principle” [6].
2. How can anything change? If everything is really one stuff, how does it become trees, rocks, and people, and then stop being them?

Each thinker’s answer creates a problem for the next one, so they read best in order. The timeline shows roughly when each one lived, with dates from the encyclopedia entries [7], [6], [8], [2], [3], [9], [1], [10], [11], [12], [13].

Roughly when each one lived. Solid bars are life spans the sources give. Dashed lines are estimates from a single date, like a birth year or a year someone was active around. Filled marks are the Ionians, hollow ones the Italians, and grey the atomists. The shaded band is Socrates.

Which source to trust

The podcast and the encyclopedias tell the same story but don’t always agree on the facts. The podcast says Pythagoras worked out musical harmony by listening to blacksmiths’ hammers [5], and the Stanford encyclopedia says that couldn’t have happened [3]. Disagreements like that come up all through this primer, and each time it sides with the encyclopedias, because of how each source gets made.

Philosophize This! is a podcast by Stephen West that walks through the history of philosophy one episode at a time. It’s one person retelling the story, built to be entertaining, with jokes and pop-culture comparisons that make the ideas stick. That makes it a good way in, but it also passes along legends because they’re good stories. The host keeps the blacksmith story because every source the host read tells it, so “there has to be some merit to the story” [5]. A story showing up everywhere only shows it got copied a lot. The host says as much himself at one point: “Don’t quote me on anything specific” [5].

The Stanford Encyclopedia of Philosophy (SEP) is a free online reference published by the Metaphysics Research Lab in Stanford University’s philosophy department [14]. Each entry is written and kept up to date by a specialist in that topic. Authors are invited, they need a PhD and published, peer-reviewed work on the subject, and every entry and every major revision is checked by an editorial board before it goes up [15], [14]. The Internet Encyclopedia of Philosophy (IEP) works the same way on a smaller scale. It’s free, peer-reviewed, written by professional philosophers, and edited by professors [16].

The encyclopedias aren’t infallible. Their authors disagree with each other, and the entries say so when the evidence is thin, which is part of why they’re more trustworthy on facts. The podcast is still the friendlier place to start, and this primer keeps its order.

Before them: the gods explained everything

The standard explanation of the world at the time was Hesiod’s Theogony, a 7th-century BCE poem about the origins of the gods [1]. Storms, earthquakes, and winds that wrecked ships were the gods doing something in the god realm. The Presocratics didn’t necessarily stop believing in gods, but they started looking for explanations that came from nature itself and that you could argue about [4].

Why “Presocratic” is an awkward name

The label groups these thinkers by what came after them. It was coined in the eighteenth century and made standard by the scholar Hermann Diels in the nineteenth, to contrast Socrates, who cared about ethics (how to live), with predecessors who cared about cosmology (how the universe is put together) [1]. It has two problems. It suggests they were a warm-up act, and it isn’t even accurate as a date range, because some of them were alive at the same time as Socrates. Democritus, born around 460 BCE, was a younger contemporary of his [12]. Everyone still uses the name because there isn’t a better one.

Two regions

The podcast splits them by geography, and the split lines up well with how they thought [4]:

The atomists (Leucippus and Democritus) came later and don’t sit cleanly in either one. Democritus was from Abdera, in northern Greece, and Leucippus is said to have been born in Elea, Abdera, or Miletus, depending on the source [11].

Roughly, the Ionians looked at the physical world and tried to name the stuff underneath it, and the Italians leaned toward numbers, logic, and reasoning that could overrule what you see.

Sorting them by region and by their answer to “what is everything made of?” puts each one in a box. Thinkers who share a box usually get grouped as a school, and those are the names scholars use for them: the Milesians, the Pythagoreans, the Eleatics (after the city of Elea), the Pluralists, and the Atomists [1].

The schools, by region and answer, with the rows roughly in the order they came. Heraclitus is the hardest to place, since his fire may be a basic stuff or a symbol of constant change, and Leucippus's birthplace is uncertain, so the Atomists sit with Democritus's home city of Abdera.

The Milesians: one basic stuff

Three thinkers from the city of Miletus, each usually described as the student of the one before, gave the first answers to “what is everything made of?” All three were monists: they thought everything is ultimately one kind of thing [4].

Thales: water

Aristotle names Thales as the first person to look for the causes and principles of nature, around the beginning of the 6th century BCE [1]. His answer was water. Water is everywhere, every living thing needs it, and it shows up as a solid, a liquid, and a vapor, so it’s easy to see how it could become anything [4]. He also seems to have thought the earth floats on water, like a log or a ship [7].

Two other things he’s known for:

• The magnet had a soul. Aristotle reports that Thales said a lodestone (a naturally magnetic rock) has a soul because it moves iron, and that “everything is full of gods” [7]. This sounds strange until you notice that for him “soul” meant whatever makes something move on its own, and a magnet does that.
• The olive press story. Aristotle tells how Thales, reproached for being poor, predicted a big olive harvest, rented every olive press in Miletus and Chios ahead of time, and then rented them out at a profit when the harvest came, just to show he could [7]. The podcast has him predicting it from rainfall [4]. Aristotle says he worked it out from the stars.

Anaximander: the boundless

Anaximander didn’t think the basic stuff could be water or any other ordinary element. He called it to apeiron, usually translated “the boundless” or “the indefinite”: something with no limits and no particular qualities, that all the familiar elements come out of [6], [1].

He also had a theory about where people came from. Human babies need years of care before they can survive, so the first humans couldn’t have started out as babies on their own. His answer was that people first developed inside fish-like creatures and came out once they could take care of themselves [6]. Some people read this as an early theory of evolution. The podcast says it isn’t, and the encyclopedia calls that reading anachronistic [4], [6].

Anaximenes: air

Anaximenes went back to one ordinary substance, air, but added something the other two didn’t have: a mechanism. Air becomes other things by thinning out (rarefaction) or packing together (condensation). Thinned out, it’s fire. Condensed, it becomes wind, then cloud, water, earth, and finally stone [8]. He even backed it up with a test you can try: blow on your hand with your mouth open and the air feels warm, blow through pursed lips and it feels cool, so thin goes with hot and dense goes with cold [8].

This is the first answer to the second question. Change is the one stuff getting denser or thinner.

Anaximenes' ladder. Everything is air, thinned out toward fire or packed down toward stone.

Heraclitus: everything changes

Heraclitus of Ephesus was active around 500 BCE and wrote in short, riddling sayings [2]. He has a reputation as the meanest philosopher, and the podcast enjoys the stories: turning down an invitation from the king of Persia, insulting the citizens who asked him to write their laws, and dying after burying himself in manure to cure dropsy, a swelling caused by fluid building up in the body [4]. Most of those stories were probably invented later to match the personality people read into his writing [2].

His ideas:

• The logos. Everything is governed by a logos, an order or law that runs through all things. It’s there for anyone to understand, but most people live as if they had their own private understanding [2].
• Unity of opposites. Opposites are connected and depend on each other. “Sea is the purest and most polluted water: for fish drinkable and healthy, for men undrinkable and harmful” [2]. Day and night, hot and cold, hungry and full each only mean something next to the other [4].
• Flux. Things are always changing. Fire, the most changeable element, stands for this, an “everliving fire, kindling in measures and being quenched in measures” [2].

The river

His most famous line is “you can’t step into the same river twice,” but those aren’t his words. That version comes from Plato’s paraphrase. The fragment scholars accept as his reads [2]:

On those stepping into rivers staying the same other and other waters flow.

Plato’s version says nothing stays the same. The original says the river stays the same river because the water keeps flowing through it, a bit like a candle flame or your own body. One reading is that some things only stay what they are by constantly changing [2]. The extreme version came from a later follower named Cratylus, who reportedly said you can’t step into the same river even once, and Plato may have picked up his reading of Heraclitus from Cratylus [2], [4].

Pythagoras: numbers and the soul

Pythagoras lived from about 570 to 490 BCE. He grew up on the island of Samos and around 530 BCE moved to Croton in southern Italy, where he gathered a community of followers [3]. He’s the hardest of them to pin down. He wrote nothing, his followers revered him, and most of what’s written about him comes from authors living centuries later who were busy turning him into a legend [3]. Because of that, ideas get credited to “the Pythagoreans” as a group [5].

The safest things to say:

• He believed in reincarnation. The soul survives death and is reborn, including in animals. A poet who lived at the same time, Xenophanes, mocked him for it with a story about Pythagoras stopping someone from beating a puppy: “stop, don’t keep hitting him, since it is the soul of a man who is dear to me, which I recognized, when I heard it yelping” [3].
• His community had a way of life. The podcast describes it as strictly vegetarian, since an animal might have a reborn person inside it [5]. The ancient sources disagree, and the encyclopedia concludes he probably banned some foods but not all meat [3].
• He took numbers very seriously. The early evidence describes a cosmos “structured according to moral principles and significant numerical relationships,” and one later writer says he likened “all things to numbers” [3].

Music and ratios

The best example of numbers explaining something real is music. The intervals that sound good together are simple ratios: an octave is 2:1, a fifth is 3:2, and a fourth is 4:3 [3]. On a stringed instrument, those ratios are lengths of string. Halve the length that vibrates and the note goes up an octave. Two-thirds of the length gives a fifth, and three-quarters gives a fourth. If something as emotional as harmony comes down to whole numbers, it’s not a big leap to think the whole universe might.

The same string stopped at simple fractions of its length gives the intervals that sound good together.

The story goes that Pythagoras worked this out listening to blacksmiths, with hammers of different weights ringing out different notes [5]. It can’t have happened that way. The pitch of a hammer isn’t proportional to its weight, so none of the methods credited to him would actually work [3].

Things he probably didn’t do

• The Pythagorean theorem. The earliest sources never connect him with it, and there’s “not a jot of evidence for a proof by Pythagoras.” At most he might have known the rule, possibly from Babylonian math [3].
• Coining the word “philosopher.” The story first appears in a later writer, and the idea of a philosopher it uses is Plato’s, so historians doubt it [3]. The podcast repeats it [5].

Parmenides: nothing changes

Parmenides was born around 515 BCE in Elea, a Greek colony in southern Italy, and wrote one poem [9]. In it a goddess takes him aside and explains the truth about reality, then tells him what mortals mistakenly believe [9]. Where the Ionians looked at the world and guessed, Parmenides started from a premise and followed it step by step to whatever had to follow from it. That’s deductive reasoning, and it’s why the podcast calls him the dark cloud hanging over everyone before him [5].

The argument, simplified:

1. What is, is. What is not, is not. You can’t think about or talk about “what is not,” because there’s nothing there to think about [9]. Try picturing pure nothing, and whatever you picture is something.
2. For something to come into existence, it would have to come from what is not. That’s impossible, so nothing comes into existence and nothing is destroyed [9].
3. Change means something becoming what it wasn’t before, so that’s ruled out too. So is motion, which means being where you weren’t [5].
4. So reality is one thing: whole, unchanging, eternal, and complete, which he compares to a perfectly round ball [9].

This contradicts everything you see, and Parmenides knew it. His answer was that when reason and your senses disagree, believe reason [5]. That idea, more than the conclusion itself, outlived him.

Zeno

Zeno of Elea, a younger associate of Parmenides, wrote paradoxes showing that ordinary ideas about motion, and about there being many things at all, lead to contradictions. He’s usually described as defending Parmenides, but that story comes from Plato, and the encyclopedia argues the evidence doesn’t support it [17]. The most famous paradox is the dichotomy: to get anywhere, you first have to get halfway there, and before that, halfway to the halfway point, and so on forever. If a distance can be divided without end, you’d have to finish infinitely many trips just to start moving [17], [4].

The dichotomy. Each step covers half of what's left, so there's always another step.

Answering Parmenides: unchanging pieces that move around

The thinkers after Parmenides couldn’t refute his argument, but they couldn’t accept that the world they lived in was an illusion either. Their compromise was the same idea in different versions: keep his rule that the basic stuff never comes into being or changes, but have more than one of it, and explain the changes we see as those pieces mixing, separating, and rearranging [1], [5]. Believing in more than one basic stuff is called pluralism, the opposite of monism.

Empedocles: four roots, love and strife

Empedocles of Acragas, in Sicily, worked in the middle of the 5th century BCE [10]. He said everything is made of four roots, earth, water, air, and fire, which never change themselves. A tree or a person is just a recipe of those four in some proportion, the way a painter mixes a few pigments into every color [10], [5].

The roots don’t move on their own, so he added two forces to move them: Love, which brings them together, and Strife, which pulls them apart. The world goes through a long cycle of one force winning, then the other [10]. Nobody before him had said what actually moves the basic stuff around, so a force separate from the matter was a real step forward [5].

He also told a strange story about how living things started: body parts wandering around on their own until they combined, “many faces without necks, naked arms wandered about, bereft of shoulders” [10]. Combinations that worked survived, which the podcast compares to natural selection [5].

He was also a showman who said he was a god, and the legend says he jumped into the volcano Etna to prove he was immortal [5]. The encyclopedia is blunt that he didn’t [10]. His four elements went on to become standard after Aristotle adopted them [5].

The atomists: atoms and void

Leucippus and Democritus, who was his student or associate, went further. Everything is made of tiny, solid pieces that can’t be cut or divided, called atoms (from the Greek for “uncuttable”), moving around in empty space, the void [11], [12]. Atoms differ only in shape, position, and arrangement, and everything else is atoms combining and coming apart [1].

This was a direct reply to Parmenides [11]. Each atom behaves like his “one”: it never comes into being, never changes, and has no parts. There are just a lot of them, and they need empty space to move around in. Parmenides said empty space was impossible, so on that point the atomists broke with him [4]. An indivisible smallest piece also gets around Zeno’s dichotomy, since you can’t keep cutting a distance in half forever if there’s a smallest size [4].

Democritus also concluded that most of what we sense isn’t really out there. Taste, temperature, and color come from how atoms affect us, not from the atoms themselves [12]:

By convention sweet and by convention bitter, by convention hot, by convention cold, by convention color; but in reality atoms and void.

Side by side

The threads

Two arguments run through the whole period and keep going long after it.

Change. Heraclitus says everything is always changing. Parmenides says nothing ever does. Empedocles and the atomists split the difference: the basic pieces never change, and what we call change is those pieces moving around. Modern chemistry still works roughly that way, with elements that rearrange into compounds.

Three answers to how change works.

Reason or the senses. The Pythagoreans, Parmenides, and Democritus all trusted reasoning over what they could see. Parmenides followed an argument to the conclusion that motion is impossible, Democritus decided color and taste aren’t real, and the podcast traces the same preference from the Pythagoreans forward to Plato [5]. Nearly everything these thinkers concluded about the physical world turned out to be wrong, but the habit of trying to explain the world with arguments other people can check started here [4].

References

Every source cited across the primers is collected on one page.