Introduction
Philosophy traditionally begins in 585 BC, because Thales foretold the solar eclipse of this year. This is very symbolic for the shift in thinking that happened with the Presocratics: to know the truth of things, we don’t have to rely solely on tradition and experience, we can employ reason as well! In other words, nature can be explained without needing to refer to anything beyond nature itself. This is the birth of both the philosophical and the scientific tradition in the West.
The Presocratics however are not a unified school of thought, their opinions differ in many ways. It’s even slightly incorrect to call these Greek thinkers philosophers as they were active in many other fields (astronomy, mathematics, engeneering, rhetorics, etc.). To reiterate, what unified these thinkers was their effort to base their assertions on evidence and reason. (even though in some cases we may found some gaps in their explanation attributed to the supernatural)
The way these early thinkers express their ideas is to a large part shaped by their societies being still more oral than literary. The language they used did not yet have many necessary technical terms for them to express their ideas clearly, therefore the analogies, arguments and paradoxes they use may often seem a bit strange to us.
No Presocratic book has survived intact so what we know is gathered from other philosophers. The evidence is of two sorts: direct quotations (called the fragments) and summaries or references to the thinkers and their views (called testimonia)
Philosophers
- Milesians (Thales, Anaximander, Anaximenes)
- Pythagoras (and the Pythagoreans)
- Eleatics (Xenophanes, Parmenides, Zeno of Elea)
- Heraclitus
- Empedocles
- Democritus
(I decided to categorise the Sophists among Socratic Philosophy as they were contemporaries of Socrates)
Other less known presocratic philosophers I didn’t cover include: Anaxagoras of Clazomenae, Melissus of Samos, Philolaus of Croton, Diogenes of Apollonia.