DIOGENES rightly answered one who desired letters of recommendation from him, "At first sight he will know you to be a man: and whether you are a good or a bad man, if he hath any skill in distinguishing, he will know likewise; and, if he hath not, he will never know it, though I should write a thousand times." Just as if you were a piece of coin, and should desire to be recommended to any person as good, in order to be tried: if it be to an assayer, he will know your value, for you will recommend yourself. We ought, therefore, in life also, to have something analogous to this skill in gold; that one may be able to say, like the assayer, Bring me whatever piece you will, and I will find out its value: or as I would say with regard to syllogisms. Bring me whoever you will, and I will distinguish for you, whether he knows how to solve syllogisms or not. Why? Because I can solve syllogisms myself, and have that faculty, which is necessary for one who knows how to find out persons skilled in the solution of syllogisms. But how do I act in life? I at some times call a thing good; at others, bad. What is the cause of this? The contrary to what happens in syllogisms: ignorance and inexperience.
EPICTETUS. DISCOURSES. Book iii. §2. ¶1, 2.