As it turns out nearly all of the various cosmologies proposed by the early Greek philosophers are profoundly and demonstrably false, but this does not diminish their importance. For, even if later philosophers summarily rejected the answers they provided, they could not escape their questions.
And just as important as the questions they asked was the method they followed in forming and transmitting their answers. The pre-Socratic philosophers rejected traditional mythological explanations for the phenomenon they saw around them in favor of more rational explanations. In other words they depended on reason and observation to illuminate the true nature of the would around them, and they used rational argument to advance their views to others. And though there has been a great deal of argument about the relative weights that reason and observation should have, philosophers for over two thousand years have been basically united in the use of the very method first used by the pre-Socratics.
Pre-Socratic philosophers are often very hard to pin down, and it is sometimes very difficult to determine the actual line of argument they used in supporting their particular views. This problem arises not from some defect in the men themselves or in their ideas, but is simply the result of their separation from us in history. While most of these men produced significant texts, we have no complete versions of any of those texts. All we have is quotations by later philosophers, historians, and the occasional textual fragment.
Pre-socratic philosphers include: