HERACLITUSEphesus, approx. 540 - approx. 475 B.C.
One of the youngest Ionian philosophers, known as "the dark one" due to his pessimistic style, along with "the one that cries" contrary to the always joyful Democritus. He took part in the political struggles of his hometown, committed to the aristocrats. His elitism made him express an endless hatred toward the "demos", the common people, and those who supported democratic movements. This contempt made him turn against many contemporary and earlier philosophers. However he is considered one of the deepest thinkers of the ancient world, and it is fair to say that modern science considers him, along with Democritus, one of the forefathers of physical science and the atomic age.
Opposite to the Eleatics who spoke about the eternal stillness of everything, he believed in the constant movement and change of the universe, nothing remains as it was, everything alters each passing moment. Everything that is created is the effect of a struggle between two opposing forces, and that is what brings harmony. Without this struggle, life would not exist. That is why he states that war of the elements, is the "father of everything", wherever hot prevails , there is movement and conscience, whereas excess of cold means death and stillness. There has been plenty of light shed on the dark theories of the Ephesians' philosopher.