Heraclitus (c. 535 – c. 475 BCE) was a pre-Socratic Greek philosopher, born to an aristocratic family in Ephesus, present-day Turkey. Little is known about his early life and education, but he regarded himself as self-taught and a pioneer of wisdom. He is famous for his insistence on ever-present change in the universe, as stated in his famous saying, “No man ever steps in the same river twice” .

All men have the capacity of knowing themselves.