Of the thousands of brilliant and elegant persons like ourselves who believe roughly in the Darwinian doctrine, how many are there who know which fossil or skeleton, which parrot’s tail or which cuttle-fish’s stomach, is really believed to be the conclusive example and absolute datum of natural selection? . . . What we know, to use a higher language, are the fruits of the spirit.  We know that with this idea once inside our heads a million things become transparent as if a lamp were lit behind them: we see the thing in the dog in the street, in the pear on the wall, in the book of history we are reading, in the baby in the perambulator and in the last news from Borneo.  And the fulfilments pour in upon us in so natural and continual a cataract that at last is reached that paradox of the condition which is called belief.