Presocratic philosophers have left a remarkable mark on the history of Western philosophy: Tales , Anaximenes , Heraclitus, they sought a final sense on which to postulate the universe. However, lacking scientific resources as we understand them today, this declaration of unity in the early Greek philosophers cherished a profound metaphysical intuition.
Indeed, the early observations of the Presocraticson the common principle of nature went beyond the formulation of a scientific hypothesis that time would find false. Because it was not simply a question of sharpening empirical observation, nor of sustaining itself on the creative fantasies built by mythological tradition. The change present in the world must have an earlier principle: unity. Because in the world, they sensed a whole, that is, a system supported by common laws, a same reality.
How could the world be one and many things in turn? Could diversity be an appearance? Such was the question which Parmenides believed to answer in the affirmative. Empédocles, meanwhile, thought to solve the issue by postulating a reality combined from four elements. But the question did not seem to be answered. Heraclitus could not even do it even though his thought was around the notion of unity in diversity. It would be only Plato and Aristotle who would eventually have the opportunity to seek a new answer to this ancient concern of Greek philosophers.