Naturalism

Naturalism is a phylosophical movement that appeared in VIII B.C.E.
Naturalism is the phylosophical idea that explains that the laws and behaviour of the nature are explained by the same nature not by gods or starnge powers.
Tales of Miletus explain what nature really is, he said what is governed by the laws of nature and not by gods.

Anaximandros create the atomic theory, it said that everything in this world is made of very invisible pieces that are connected each other. Also he said that everything it's like a puzzle and all this pieces have to match, this pieces have their own shape and their own function.
In this time everyone was trying to understand the nature.