A key element of Heraclitus cosmology is its reference to fire as the principle and substrate of all natural processes. But apart from the material element of the fire, Heraclitus also mentions another kind of fire, the thunderbolt, which is characterized by the existence of intellect. His cosmology, however, is characterized by the ekpyroseis, that comes from the advancing of fire which is called in Greek κόρος (= saturation) and is related to the phenomenon of ekpyroseis where everything is destroyed in the fire from which comes life and death in the Universe. The theory of ekpyroseis which refers to the constant alternation between the birth and the death of the Universe is analogous to the theory of Big Crunch.
