I well know that, not being a literary man, certain presumptuous persons will think that they may reasonably deride me with the allegation that I am a man without letters. Stupid fellows! Do they not know that I might reply as Marius did in answering the Roman patricians, by saying that they who adorn themselves with the labours of others, will not concede to me my very own: they will say that, not having learning, I will not properly speak of that which I wish to elucidate. But do they not know know that my subjects are to be better illustrated from experience than by yet more words? — experience which has been the mistress of all those who wrote well, and, thus as mistress, I will cite her in all cases.
–Leonardo da Vinci