Only one of this philosopher's works, "On Nature", survives, in which he argued that all existence was in flux, being constantly formed from or destroyed by fire, which he posited was the fundamental substance.
Though Pythagoras may have coined the word "kosmos", this man was the first to use it in any extant text, and he claimed the universe had a fundamental unity he termed "logos." He expressed the intrinsic similarity in being asleep and awake in his "unity of opposites" theory. Only one of this philosopher's works, "On Nature", survives, in which he argued that all existence was in flux, being constantly formed from or destroyed by fire, which he posited was the fundamental substance. For 10 points, name this ancient philosopher, known for positing that one cannot step into the same river twice.
Though Pythagoras may have coined the word "kosmos", this man was the first to use it in any extant text, and he claimed the universe had a fundamental unity he termed "logos."
{Heraclitus}