The pre-Socratic Philosophers are not primarily significant for the truths that they discovered, but because they were the first thinkers to think of knowledge as a whole. They weren’t concerned with, for example, the motion of a rolling ball, or of a shooting arrow, but with the concept of motion as a whole. Zeno of Athens, for example, argued that motion is impossible. Heraclitus, however, argued that permanence is an illusion, and that reality is change.
Another important concept in pre-Socratic philosophy is concept that the universe is composed of a fundamental element. Thales of Miletus posited that the fundamental element must be water. Anaximines said that the fundamental element must be air. Today we know that these ideas are false. but it is not important if what they posited was true. What is important is that they were thinking in a way that was new; what and how rather than who and why.