Philosophy started with astronomy or material science?

Philosophy probably started with astronomy, because the first Greek philosophers were astronomers. Primarily, this knowledge is used to navigate; the stars become their guides for navigation. With philosophy, men grew bold enough to attempt explaining processes before attributing them to supernatural agencies and powers.

But first, this philosophy was physical. Ancient people looked at the material world and asked questions about what was the final constituent of things, which resulted in Democritus' thought of materialism. He was an ancient pre-Socratic philosopher who lived in Greece between 460 and 370 BC. He is remembered for developing the atomic theory of the universe.

Leucippus, another pre-Socratic philosopher, was the mentor of Democritus, credited as the first philosopher to develop a theory of atomism. Democritus's speculation of atoms was taken from his mentor Leucippus. Their contribution has a partial resemblance to the atomic theory of the nineteenth century. So, some consider Democritus more of a scientist than a philosopher. Even though none of his writings have survived, many considered him the "father of modern science."