Heraclitus of Ephesus was a pre-Socratic Greek philosopher, a native of Ephesus on the coast of Asia Minor. He is known for his doctrine of change being central to the universe, and that the Logos is the fundamental order of all.
His great achievements were to have understood the nature of the infinite, which includes understanding the inherent contradictoriness and negativity of reality, and to have grasped that reality is constantly becoming or in process, and that being and nothingness are empty abstractions. Heraclitus’s obscurity comes from his being a true philosopher who grasped the ultimate philosophical truth and therefore expressed himself in a way that goes beyond the abstract and limited nature of common sense and is difficult to grasp by those who operate within common sense.
Heraclitus considered that the being of all the universe is fire. According to him, the being is material and one, but at the same time he acknowledged that the world witnesses constant change.
Motion of the archelement fire is discordant and unharmonious, even though harmony is the final result of the process. This change, the transformation of material from one state into another, does not happen by accident, but rather according to law within certain limits and within certain time. This law is named Logos by Heraclitus.
In addition to seeing fire as the most fundamental of the four elements and the one that is quantified and determines the state of the other three, Heraclitus presents fire as the cosmos, which was not made by any of the gods or men, but was and is ever living fire. This is the closest he comes to a substance, but it is an active one altering other things quantitatively and performing an activity he describes as the judging and convicting of all things. It is the thunderbolt that steers the course of all things.