Heraclitus (540-480 BC), the philosopher who first discussed the phenomenon of change in the universe with a very strong emphasis, gained fame with his thesis that "everything is in flux".
However, flow and change constitute only one aspect of Heraclitus' philosophy. Indeed, his concern and philosophy focus on two main perspectives: the objective and endless processes of nature on the one hand, and the beliefs and values of ordinary people on the other. Accordingly, while he argues that there is a constant change and flow in that world, he also criticizes people for not being able to deal with the fact in question, theoretically and practically, with the fact that they live in a world that is always a burning and extinguishing fire, apart from the fact that they were not created by man or God.
Heraclitus (500 BC) was an ancient Greek pre-Socratic philosopher from the city of Ephesus, which was then part of the Persian Empire. Little is known of Heraclitus's life. He wrote a single work, only fragments of which have survived. Most of the ancient stories about him are thought to be later fabrications based on interpretations of the preserved fragments. His paradoxical philosophy and appreciation for wordplay and cryptic, oracular utterances has earned him the epithet "the obscure" since antiquity. He was considered arrogant and depressed, a misanthrope who was subject to melancholia.
At the center of Heraclitus' views is the idea that conflict and war are the father of everything. According to him, war is the single most important condition of existence or becoming. For without this war, nothing would exist. Therefore, the birth or coming into existence of beings depends on the conflict of opposing forces that are opposite to each other and therefore keep each other in existence. Not only is the war of opposites a bad thing, but Heraclitus, who argues that it is a sine qua non of existence and that all beings in the universe must consist of opposing elements or forces in order to maintain their existence, Heraclitus opposes the Pythagorean view of the ordered and harmonious universe. Health, peace, and tranquility, taken on their own, cannot be said to be any better than their counterparts; they are good only when they are evaluated together with their opponents. It is necessary and correct to consider together what a Pythagorean philosopher would see as good and bad, but this is not enough.
According to Heraclitus, who asserts not only the war but also the unity of the opposites, each of the pairs of opposites then constitutes both a unity and a multiplicity, thus the fundamental moments of formation and change in the universe. In other words, the doctrine of the unity of opposites leads directly to the doctrine of flow. Because Heraclitus, like other Greek philosophers, accepted that change is cyclical, depending on the concept of the cyclicity of time. Accordingly, the change takes place from one of the opposites originally existing in one and the same being in the other. The cyclical change process in question constitutes another of the most fundamental theses of his view of existence.
Like other Greek philosophers, Heraclitus, who accepts that nothing can come out of nothing and therefore argues that the first matter is eternal, finds this unity in the fire. According to him, when fire condenses, for example, it becomes moist and turns into water under pressure. When water freezes, it turns into soil.