The Timpson Lyceum · History of Philosophy (2024)

Historical Context and Thales of Miletus – Lecture 2 (History of Philosophy)

Overview

Before meeting the first philosopher, this lecture builds the world he was born into — because philosophy is in large part a response to its environment. It sketches world history up to roughly 500 BC: the two great river civilizations of Egypt (stable, unified, geometry-rich thanks to Nile-flood land surveying) and Mesopotamia (fickle rivers, warring city-states, a base-60 number system and sky-watching that still shapes our clocks and calendars); the Bronze Age collapse (~1100 BC) that erased most of the Mediterranean world but which Egypt and Babylon survived; and the rise of Lydia and then Persia. It then turns to the Greeks: scattered by colonization into an "information highway" of trading city-states, split culturally toward Sparta (a rigid, communal warrior state — the "Godfather" of Greece) and Athens (moving from Draco's harsh code to Solon's foundations of democracy).

Against this backdrop arrives Thales of Miletus (~624–546 BC), traditionally counted the first philosopher and one of the Seven Sages. He is the first of the physikoi — the natural philosophers who tried to explain the cosmos not by myth but by a single underlying principle.

Key Concepts

• Why philosophy began with the Greeks — A shared education (physical + "musical," i.e. the Muses: Homer and Hesiod), political freedom in independent poleis, and a trade-driven flow of information exposed them to Egyptian and Babylonian learning while leaving them free to question inherited myth.
• Physikoi (natural philosophers) — Early thinkers Aristotle labels physikoi; they practice "natural philosophy" — what we would now simply call science.
• Arche (ἀρχή) — The fundamental principle, source, or underlying stuff from which everything comes and of which everything is ultimately made. The central question the Milesians pose: what is the one thing underlying the many?
• Thales' answer: water — The arche is water. Everything ultimately is, or comes from, water — a bold move because it seeks one natural substance behind all phenomena instead of a pantheon of gods.
• Hylozoism — The view (attributed to Thales in "all things are full of gods") that matter itself is in some sense alive or self-moving, blurring the line between the living and the non-living.
• Thales the geometer — Credited with bringing Egyptian surveying know-how into deductive geometry, including Thales' theorem (an angle inscribed in a semicircle is a right angle) and measuring a pyramid's height by its shadow.
• Thales the astronomer — Reputed to have predicted the solar eclipse of 585 BC, and (per Aristotle) to have cornered the olive-press market after forecasting a good harvest — showing that "impractical" contemplation can be powerful. The counter-anecdote (falling into a well while stargazing) captures the stereotype of the absent-minded philosopher.
• Egypt vs. Mesopotamia (as knowledge sources) — Egypt's stability preserved geometric knowledge; Babylon's sky-watching gave us the sexagesimal (base-60) legacy: 60 seconds, 60 minutes, 360°, 12 months.

Worked Example

Thales' theorem — any angle inscribed in a semicircle is a right angle. A clean specimen of the deductive geometry Thales helped inaugurate.

1. Let $AB$ be a diameter of a circle with center $O$, and let $C$ be any other point on the circle. Claim: $\angle ACB = 90^\circ$.
2. Draw radius $OC$. Then $OA = OB = OC$ (all radii), so triangles $OAC$ and $OBC$ are isosceles.
3. Isosceles $\triangle OAC$ gives equal base angles: let $\angle OAC = \angle OCA = \alpha$.
4. Isosceles $\triangle OBC$ gives equal base angles: let $\angle OBC = \angle OCB = \beta$.
5. The angle at $C$ is $\angle ACB = \alpha + \beta$.
6. The angles of $\triangle ABC$ sum to $180^\circ$: $\;\alpha + \beta + (\alpha + \beta) = 180^\circ$.
7. Hence $2(\alpha + \beta) = 180^\circ$, so $\alpha + \beta = 90^\circ$.
8. Therefore $\angle ACB = 90^\circ$ for every choice of $C$ on the circle. $\blacksquare$

Summary

• Philosophy is born from a specific setting: literate, free, well-traveled Greek city-states inheriting Egyptian geometry and Babylonian astronomy while feeling free to challenge myth.
• The Bronze Age collapse reset the Mediterranean; Egypt (stable, unified) and Babylon (wealthy, sky-watching) preserved knowledge that later reached the Greeks.
• Sparta (conservative, communal, militarized) and Athens (Draco → Solon → toward democracy) are the two poles of the Greek world to keep in mind throughout the course.
• Thales of Miletus, the first philosopher, asks the founding question — what is the arche? — and answers water, replacing mythic explanation with a search for one natural underlying substance.
• Thales also exemplifies philosophy's reach: real results in geometry (Thales' theorem) and astronomy (the 585 BC eclipse), and the lesson that contemplation is not idle.