It was not really what we would know as science, as it does not revolve around strictly constructed experimentation, hypothesis, or reproduceablility or predictivity, so much as it was the concepts of logic itself, of arguing about things with rationality and rhetoric.

A whole lot of Greek philosophy uses what seem like decent arguments to lead to decent sounding explanations that do not actually work if explored further or tested, though there are genuine examples of actual experimentation that still hold up fairly well, like Eratosthenes approximating the size of the Earth based on geometry and shadows.

Theyre basically just known for formally getting the ball rolling of inquisitive discourse on the nature of the world.