“It is impossible for a man to learn what he thinks he already knows.” — Epictetus

“There is only one way to happiness and that is to cease worrying about things which are beyond the power or our will. ” — Epictetus

“You become what you give your attention to.” — Epictetus, The Art of Living: The Classical Manual on Virtue, Happiness and Effectiveness

“Be discriminating about what images and ideas you permit into your mind. If you yourself don’t choose what thoughts and images you expose yourself to, someone else will, and their motives may not be the highest.” — Epictetus, The Art of Living: The Classical Manual on Virtue, Happiness, and Effectiveness

“Most of what passes for legitimate entertainment is inferior or foolish and only caters to or exploits people's weaknesses. Avoid being one of the mob who indulges in such pastimes. Your life is too short and you have important things to do. Be discriminating about what images and ideas you permit into your mind. If you yourself don't choose what thoughts and images you expose yourself to, someone else will, and their motives may not be the highest.

“Any person capable of angering you becomes your master; he can anger you only when you permit yourself to be disturbed by him.” — Epictetus

“The definition of insanity is doing the same experiment and expecting different results.” — Albert Einstein

“When the power of love overcomes the love of power, the world will know peace.” — Jimi Hendrix

“The more I read, the more I acquire, the more certain I am that I know nothing.” — Voltaire

“He who thinks he knows, doesn't know. He who knows that he doesn't know, knows.” — Joseph Campbell