The wise are instructed by reason, average minds by experience, the stupid by necessity and the brute by instinct. - Marcus Tullius Cicero
I've studied now
And Jurisprudence, Medicine,
And even, alas! Theology
All through and through with ardour keen!
Here now I stand, poor fool, and see
I'm just as wise as formerly. - Johann Wolfgang von Goethe
Those who can, do; those who can't, teach. - George Bernard Shaw