Cogito, ergo sum. (I think, therefore I am.)
“Uneasy lies the head that wears a crown.”
“Happiness depends upon ourselves.”
“A goal without a plan is just a wish.”
“It's not what happens to you, but how you react to it that matters.”
“If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.”
“Unthinking respect for authority is the greatest enemy of truth.”