EVERYTHIN IS FLUX.
HERACLITUS (535–475 BCE).
Where other early Greek philosophers seek to uncover scientific explanations for the physical nature of the cosmos, 
Heraclitus sees it as being governed by a divine logos.
Sometimes interpreted to mean “reason" or “argument", Heraclitus considers the logos to be a universal, cosmic law, 
according to which all things come into being, and by which all the material elements of the universe are held in balance.
It is the balancing of opposites, such as day and night and hot and cold, which Heraclitus believes leads to the unity of the universe, 
or the idea everything is part of a single fundamental process or substance—the central tenet of monism.
But he also states that tension is constantly generated between these pairs of opposites, and he therefore concludes that everything must be in a 
permanent state of flux, or change.
Day, for instance, changes into night, which in turn changes back again to day.
Heraclitus offers the example of a river to illustrate his theory: “You can never step into the same river twice."
By this, he means that at the very moment you step into a river, fresh waters will immediately replace those into which you initially placed your 
foot, and yet the river itself is always described as one fixed and unchanging thing.
Heraclitus's belief that every object in the universe is in a state of constant flux runs counter to the thinking of the philosophers of the Milesian 
school, such as Thales and Anaximenes, who define all things by their quintessentially unchanging essence.
IN CONTEXT,
BRANCH: Metaphysics,
APPROACH: Monism.
BEFORE;
6th century BCE The Milesian philosophers claim that the cosmos is made up of a single specific substance.
6th century BCE Pythagoras states that the universe has an underlying structure that can be defined mathematically.
AFTER;
Early 5th century BCE Parmenides uses logical deduction to prove change is impossible.
Late 4th century BCE Plato describes the world as being in a state of flux, but dismisses Heraclitus as contradictory.
Early 19th century Georg Hegel bases his dialectic system of philosophy on the integration of opposites.
The road up and the road down are one and the same.
Heraclitus.
