Anaxagoras, Empedocles, Leucippus, and Democritus

Anaxagoras, c. 500 - 428 BCE. Anaxagoras moved to Athens, was an associate of Pericles, was prosecuted and convicted for impiety in about 450 BCE.

"Do you think you are accusing Anaxagoras (Ἀναξαγόρου), my dear Meletus, and do you so despise these gentlemen and think they are so unversed in letters as not to know, that the books (βιβλία) of Anaxagoras the Clazomenian are full of such utterances? And forsooth the youth learn these doctrines from me, which they can buy sometimes (if the price is high) for a drachma in the orchestra [part of the ἀγορά in Athens] and laugh at Socrates, if he pretends they are his own..." (Plato, Apology 26d).

Empedocles, c. 490 - c. 430 BCE. Empedocles writes in verse, as did Xenophanes and Parmenides.

Leucippus, 5th century BCE.

Democritus, c. 460 - c. 360 BCE. Younger than Socrates. Democritus says he was young when Anaxagoras was old (DK 68 B 5). Lived when Aristotle was in the Academy.

These Presocratics are mixed geographically. Empedocles came from Acragas in southern Italy, but the others were from the east. Anaxagoras came from Clazomenae. Democritus came from Abdera. Clazomenae is north of Miletus, and Abdera is further north and east. Leucippus is an obscure figure whose life and place of birth is unknown.
Anaxagoras, Empedocles, and Leucippus and Democritus (the fifth-century Atomists) are inquirers into nature, but they take the nature of reality to consist in a plurality of objects.

The relationship of these Presocratics to Thales and the Milesians and to Parmenides is uncertain, but the ontology in Democritus and Leucippus (and also Anaxagoras and Empedocles) provide the means to defend the inquiry into nature against the threat Parmenides posed.

Leucippus and Democritus

According to Democritus and Leucippus, the nature of reality consists in atoms and void.

On the existence of the ordinary objects salient in experience, Democritus and Leucippus may have had different views. The evidence for what Leucippus thought is less certain, but Democritus seems to have thought the ordinary objects salient in experience are how the atoms in the void appear to humans beings. Democritus seems to have thought that belief in the existence of these ordinary objects and the traditional conception of reality is a product of sense-experience, that sense-experience is a "bastard" form of judgment, that this form of judgment is not knowledge, that the ordinary objects salient in experience are the way arrangements of atoms in the void appear, and that only the "legitimate" judgment of reason provides knowledge of what exists.

This way of thinking about the ordinary objects in experience is striking. It is more typical to think that these objects come into existence, persist through various changes, and eventually go out of existence, but Democritus seems to have thought that this way of thinking mistakes appearance for reality. In reality, according to Democritus, there are no such objects. Democritus accepts Parmenides' conclusion that nothing comes into or goes out of existence. The atoms exist and move in the void, but the atoms do not come into or go out of existence. They become arranged in various ways as they move aimlessly through the void, but these transient arrangements are not themselves objects and hence are not objects that come into or go out of existence.

Knowledge, Reason, and Experience

"Democritus sometimes does away with what appears to the senses, and says that none of these appears according to the truth but only according to opinion. The truth in real things is that there are atoms and void. 'By custom,' he says, 'sweet, bitter, hot, cold, color; but in truth, atoms and void'" (Sextus Empiricus, Against the Logicians I.135; DK 68 B 9).

"He says that there are two kinds of knowing, one through the senses and one through the intellect. Of these he calls the one through the intellect 'legitimate,' attesting its trustworthiness for the judgment of truth, and that through the senses he names 'bastard,' denying it inerrancy in the discrimination of what is true. To quote his actual words: 'Of knowing there are two forms, one legitimate, one bastard. To the bastard belong all this group: sight, hearing, smell, taste, touch. The other is legitimate and separate from that'" (Sextus Empiricus, Against the Logicians I.138; DK 68 B 11).

"The principles of the totality of things are atoms and the void, everything else is the object of convention (νενομίσθαι). ... Nothing comes into being from what does not exist nor is it destroyed into what does not exist. And the atoms are unlimited in magnitude and number and they move in the whole, whirling around" (Diogenes Laertius, Lives of the Philosophers IX.44).

Sextus Empiricus lived in the 2nd or 3rd century AD. He is the primary source for Democritus' epistemology. He discusses Democritus in Against the Logicians I (M VII).

"The Greeks do not conceive correctly either what it is to come to be or what it is to be destroyed. For no thing comes to be or is destroyed; but rather, out of things that are, there is mixing and separation. And so, to speak correctly, they would have to call coming to be ‘mixing’ and being destroyed ‘separating'" (Anaxagoras, DK 59 B 17. Simplicius, Commentary on Aristotle’s Physics).

"[O]f nothing is there birth, among all Mortal things, nor is there an ending coming from baleful death, But only mixture and exchange of things mixed Exist, and ‘birth’ is a name given by mortal humans" (Empedocles, DK 31 B 8. Pseudo-Plutarch, De Placita Philosophorum 1.30.1).

Pseudo-Plutarch is the conventional name of the unknown author of works that were but now are no longer attributed to Plutarch. De Placita Philosophorum (Περὶ τῶν ἀρεσκόντων φιλοσόφοις φυσικῶν δογμάτων abridges a longer work ascribed to Aëtius (first to second century CE).
Democritus seems to have thought that the traditional conception of reality as consisting of objects that come into and go out of existence is a "custom" or "convention" that has its basis in the senses. It is a "bastard" judgment, not a "legitimate" judgment in terms of reason. Human beings typically rely on their senses for their beliefs, and it is through this reliance on senses that human beings form their belief in the traditional but mistaken conception of reality in which there are objects that come into and go out of existence. Democritus accepts Parmenides' injunction to "not let habit born from much experience (πολύπειρον) compel you along this way to direct your sightless eye and sounding ear and tongue, but [instead to] judge by reason (κρῖναι δὲ λόγῳ)."

A Defense of the Inquiry into Nature

Democritus and Leucippus, with their Atomism, provide the means to defend the inquiry into nature against the argument in Parmenides that nothing comes into or goes out of existence.

Thales and the Milesian inquirers into nature may follow a "backward-turning" method, just as Parmenides suggests. They may have thought that ordinary objects exist in terms of changes in the nature of reality, but Democritus seems to have thought this ontology is not essential to the inquiry into nature. Ordinary objects do not exist and so do not exist in terms of the nature of reality. The traditional conception of reality is how the nature of reality appears to human beings when they rely on sense-experience rather than the "legitimate" judgment of reason. The inquiry into nature relies on reason to show how changes in the objects postulated in this traditional and customary way to conceive of reality are a matter of changes in the locations of atoms in the void. "By custom, sweet, bitter, hot, cold, color; but in truth, atoms and void" (Democritus, DK 68 B 9).

Perseus Digital Library:

Henry George Liddell, Robert Scott, A Greek-English Lexicon:
ἄτομος, (ἀ + τέμνω), atomos, adjective, "uncut,"
νόος, noos, noun, "intellect,"
νομίζω, nomizō, verb, "to hold or own as a custom"

Arizona State University Library. Loeb Classical Library:
Early Greek Philosophy, Volume VI: Later Ionian and Athenian Thinkers, Part 1
Early Greek Philosophy, Volume V: Western Greek Thinkers, Part 2
Early Greek Philosophy, Volume VII: Later Ionian and Athenian Thinkers, Part 2
Sextus Empiricus, Against the Logicians

"Medicine, according to Democritus, cures the illnesses of the body, but wisdom removes the soul from its affections (παθῶν)" (Clement of Alexandria, Pedagogue 1.2).

Clement of Alexandria (first to second century CE) was a Greek Christian theologian and head of the catechetical school of Alexandria (the city on Mediterranean Sea in Egypt that Alexander the Great founded in 331 BCE).
"[H]ow does it come about that, if reality is the way Parmenides describes it, we nevertheless perceive it the way we do? It was Democritus who took up this problem, and, in taking it up, had to face the question of the relative roles of thought and perception in cognition. He thus, instead of having a vague and indefinite notion of some cognitive power of thought, came nearer to having a notion of reason by trying to determine more precisely the relative role of thought in cognition. Unfortunately Democritus' thought is preserved highly selectively, and there is not much evidence concerning his views on the soul. But given that he thought of philosophy as providing therapy for the afflictions of the soul, it would seem that he, too, had a substantive notion of the soul integrating perception, thought, belief, and desire in some systematic way" (Michael Frede, "Introduction," 21-22. Rationality in Greek Thought (Oxford University Press, 1996), 1-28).

Michael Frede's A Free Will is a partially revised version of his Sather Lectures delivered in 1997/98 at the University of California, Berkeley. Frede died (in 2007 while swimming at Agios Minas, a cove east of Itea on the Gulf of Corinth in Greece) before releasing his lectures for publication. "We can hardly resist the temptation to assume wrongly that Democritus must have thought that the atoms move, collide, or rebound according to fixed laws of nature. But it is perfectly clear that Democritus has no idea of such laws. He is concerned, rather, to resist the idea that the apparent regularity in the behavior of objects be understood as the result of their being designed to behave in this fashion; for in Greek thought regularity of behavior as a rule is associated with design by an intellect. The planets are taken to be supremely intelligent, if not wise, because they move with an extreme degree of regularity. If an object is not intelligent but displays regularity in behavior, it is readily thought to do so by design of an intelligent agent. Democritus's point is that the apparent regularity of the world is not a work of design, say, by an Anaxagorean cosmic intellect but a surface phenomenon produced by the aimless, random motion of the atoms" (Michael Frede, A Free Will. Origins of the Notion in Ancient Thought (edited by A. A. Long), 13. University of California Press, 2012.)

move on go back