MEN are disturbed, not by things, but by the principles and notions which they form concerning things. Death, for instance, is not terrible, else it would have appeared so to Socrates. But the terror consists in our notion of death that it is terrible. When therefore we are hindered, or disturbed, or grieved, let us never impute it to others, but to ourselves; that is, to our own principles. It is the action of an uninstructed person to lay the fault of his own bad condition upon others; of one entering upon instruction to lay the fault on himself; and of one perfectly instructed, neither on others nor on himself.
EPICTETUS. MANUAL. 5.