It is impossible for a man to learn what he thinks he already knows.

Epictetus (50–135 CE) was a Greek Stoic philosopher who believed that philosophy was a way of life and not just a theoretical discipline. He taught that all external events are beyond one’s control, and thus one should accept whatever happens calmly and dispassionately. In addition, Epictetus believed in individual responsibility for one’s actions through rigorous self-discipline.