He [Thales of Miletus] held that the original substance of all things is water, and that the world is animate and full of deities. They say he discovered the seasons of the year, and divided the day into 365 days. (Diogenes Laertius, Lives of the Eminent Philosophers, p. 12, tr. Pamela Mensch)
My received history of philosophy begins with the beginning of that first sentence. Thales deduces or imagines, sometime in the early 6th century BCE, that all things are made of water, really, when you think about it. Heraclitus will argue: No, fire; Anaximenes says: No, air. Anaximander, a student of Thales, picks as the basis of existence “the limitless” or “the indefinite,” an interesting swerve. Maybe we are made of a mix of things, the four elements, say, or the more abstract microscopic atoms claimed by Democritus
Democritus in some sense got it right, sometimes uncannily right, but his system was as much an imaginative creation as anyone else’s. Reading the early Greeks, I am witnessing not just the birth of philosophy but a step towards the invention of science, but without the scientific method, or any other method. Water, fire, a mix: how can I tell which theory is correct? Or, to ask the question that the scientific method can answer, how can I tell which are wrong? The tools of philosophy do not have any better answers.
And how is any of this cosmogonizing different than what Hesiod does in Theogony?
Now sound out the holy stock
of the everlasting immortals
who came into being out of Gaia
and starry Ouranos
and gloomy Night, whom Pontos, the salt sea,
brought to maturity (129, tr. Richmond Lattimore)
These stories can be enjoyed literally, but they are also blatantly allegories, attempts to answer the same questions Thales is working on. Water and air and fire have proper names, that’s all.
The great conceptual innovation of Thales is linguistic, literary. He removes the names, and removes the allegory. Philosophy is what we call that. “[H]e was the first, as some say, to reason about nature” (11) writes Diogenes Laertius, which is preposterous in a sense, but that “some” includes Aristotle who, two hundred years later, was the first writer to get serious about the history of philosophy, mostly in Metaphysics. Thales is the first philosopher because Aristotle thinks he is.
Given how strong my sense was that “Water if the origin of all things” was the idea that was the origin of all ideas, it has been a genuine shock to discover that the idea of Thales is first found in Aristotle’s Metaphysics where it is likely misinterpreted as not. The horrifying details are in The Presocratic Philosophers (Kirk, Raven & Schofield, 2nd ed., pp. 89-91). We’ll never know the truth.
I have included a 17th century print, borrowed from Wikipedia and the Rijksmuseum, of Thales by Jacob de Gheyn III showing Thales doing his thing, somewhat anachronistically. At some point people no longer wanted images from Thales, but not at that point.