Note 33 — Chapter V · IRRECONCILABLE DIFFICULTIES CONNECTED WITH EVOLUTION

The difference between the brain of the orang and that of man is a mere difference of degree, and not of kind; and most students of comparative psychology now admit that the intellectual faculties of animals differ from those in man in degree only, not in their essence. Replying to his opponents, Professor Huxley compares the brain of man and that of ape with two watches, one of which will, and the other will not, keep accurate time. He exclaims: “A hair in the balance-wheel, a little rust on a pinion, a bend in a tooth of the escapement, a something so slight that only the practised eye of the watchmaker can discover it, may be the source of all the difference.”33