Parmenides from Lives of the Eminent Philosophers
Diogenes Laërtius
About Parmenides
In this selection from Lives of the Eminent Philosophers, Diogenes Laërtius introduces us to Parmenides of Elea, one of the most important (and puzzling) Pre-Socratic philosophers. Writing in the 6th–5th century BCE, Parmenides offers a radical break from earlier thinkers like Heraclitus or the Milesians. His ideas were so bold that they reshaped the way philosophers thought about existence, change, and reality itself.
Unlike Heraclitus, who believed that everything is in constant motion, Parmenides argued the exact opposite: Change is an illusion. According to him, “what is, is,” and it cannot become “what is not.” In other words, reality is one, unchanging, and eternal. Anything that seems to change, move, or come into being? That’s just an illusion cooked up by our unreliable senses.
This might sound strange, but Parmenides wasn’t being contrary for fun. He was pushing the boundaries of reason itself. If you start with the idea that something cannot come from nothing, and nothing can become nothing, then it follows (according to Parmenides) that reality must be a continuous, indivisible whole. The universe, in his view, is a kind of smooth, eternal “being”—no gaps, no changes, no beginnings or ends.
His ideas are most famously captured in a poetic work sometimes called On Nature, which survives only in fragments. What’s unique is that this philosophical argument is written in epic verse, giving it a mythic, mysterious tone. The poem features a journey narrative in which a young man is taken by a goddess along two roads: the way of truth (what is) and the way of opinion (what seems to be). The “way of truth” is Parmenides’ bold metaphysical vision; the “way of opinion” represents the deceptive world of sensory experience.
Diogenes Laërtius’ account of Parmenides gives us both context and commentary, though much of what we know comes from the poem itself and later philosophers—especially Plato and Aristotle, who took his ideas very seriously (even when they strongly disagreed).
Before You Read
Get ready for a serious shift in perspective. If Heraclitus is the philosopher of change, Parmenides is the philosopher of being. Where Heraclitus saw rivers that never stop flowing, Parmenides says, “Actually… nothing flows at all.” He’s not being poetic—he means it literally. From his point of view, all change, motion, and multiplicity are illusions.
As you read, try to suspend your usual trust in your senses. Parmenides invites us to consider: What if reality is nothing like it appears? What if the world as we perceive it is a shadow of something more unified and unchanging underneath?
This isn’t just metaphysical musing—it’s also a challenge to how we think about knowledge. Is reason more trustworthy than our senses? Can we “know” something that seems to contradict our everyday experience?
Guiding Questions
- What does Parmenides mean by “what is, is” and “what is not, is not”?
- Why does he reject the idea of change or coming into being?
- How does the “way of truth” differ from the “way of opinion” in his poem?
- How does Parmenides’ view challenge the assumptions of earlier philosophers?
Parmenides from Lives of the Eminent Philosophers
Parmenides, a native of Elea, son of Pyres, was a pupil of Xenophanes (Theophrastus in his Epitome makes him a pupil of Anaximander). Parmenides, however, though he was instructed by Xenophanes, was no follower of his. According to Sotion he also associated with Ameinias the Pythagorean, who was the son of Diochaetas and a worthy gentleman though poor. This Ameinias he was more inclined to follow, and on his death he built a shrine to him, being himself of illustrious birth and possessed of great wealth; moreover it was Ameinias and not Xenophanes who led him to adopt the peaceful life of a student.
He was the first to declare that the earth is spherical and is situated in the centre of the universe. He held that there were two elements, fire and earth, and that the former discharged the function of a craftsman, the latter of his material. 22. The generation of man proceeded from the sun as first cause; heat and cold, of which all things consist, surpass the sun itself. Again he held that soul and mind are one and the same, as Theophrastus mentions in his Physics, where he is setting forth the tenets of almost all the schools. He divided his philosophy into two parts dealing the one with truth, the other with opinion. Hence he somewhere says:
Thou must needs learn all things, as well the unshakeable heart of well-rounded truth as the opinions of mortals in which there is no sure trust.
Our philosopher too commits his doctrines to verse just as did Hesiod, Xenophanes and Empedocles. He made reason the standard and pronounced sensations to be inexact. At all events his words are:
And let not long-practised wont force thee to tread this path, to be governed by an aimless eye, an echoing ear and a tongue, but do thou with understanding bring the much-contested issue to decision.
23. Hence Timon says of him:
And the strength of high-souled Parmenides, of no diverse opinions, who introduced thought instead of imagination’s deceit.
It was about him that Plato wrote a dialogue with the title Parmenides or Concerning Ideas.
He flourished in the 69th Olympiad. He is believed to have been the first to detect the identity of Hesperus, the evening-star, and Phosphorus, the morning-star; so Favorinus in the fifth book of his Memorabilia; but others attribute this to Pythagoras, whereas Callimachus holds that the poem in question was not the work of Pythagoras. Parmenides is said to have served his native city as a legislator: so we learn from Speusippus in his book On Philosophers. Also to have been the first to use the argument known as “Achilles [and the tortoise]”: so Favorinus tells us in his Miscellaneous History.
There was also another Parmenides, a rhetorician who wrote a treatise on his art.
