Criticism is above all a gift, an intuition, a matter of tact and flair; it cannot be taught or demonstrated--it is an art. Critical genius means an aptitude for discerning truth under appearances or in disguises which conceal it; for discovering it in spite of the errors of testimony, the frauds of tradition, the dust of time, the loss or alteration of texts. It is the sagacity of the hunter whom nothing deceives for long, and whom no ruse can throw off the trail.