The Pre-Socratics asked a simple and bold question: what is the world made of, and why does it change? Instead of putting everything down to the will of the gods, they looked for a natural principle behind things, which they called the arche. Some bet on water, fire or numbers; others asked whether change is real or only appearance. With them comes the idea that nature can be understood by thinking.
They lived between the sixth and fifth centuries BC, in Greek cities in Asia Minor, Italy and Sicily. The name comes from their working before Socrates or outside his influence. Pythagoras saw numbers in the order of the universe, Heraclitus stressed constant flux, Parmenides denied change, Democritus proposed atoms, and Protagoras, already a Sophist, turned to human beings. Their questions opened the way for both philosophy and science.
Core ideas
Nature follows principles that reason can discover
Behind the variety of things lies a common origin
Change and permanence are the great riddle of the world
Where to start reading
Each thinker's starter book, picked for beginners.
