‘It may be well to remember how perfect the sense of touch becomes in a man when born blind and deaf, as are worms. If worms have the power of acquiring some notion, however rude, of the shape of an object and of their burrows, as seems to be the case, they deserve to be called intelligent; for they then act in nearly the same manner as would a man under similar circumstances.’[61] While a celebrated passage in ‘The Origin of Species’ develops the idea abstractly, by implication at least placing man at the apex of the whole: ‘As buds give rise by growth to fresh buds, and these, if vigorous, branch out and overtop on all sides many a feebler branch, so by generation I believe it has been with the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever-branching and beautiful ramifications.’[62]

Wallace said of his great friend and competitor, ‘Again, both Darwin and myself had what he terms “the mere passion of collecting”.... I should describe it rather as an intense interest in the mere variety of living things.’[63] The simple observer is carried away, absorbed, ravished by the delight and the fascinating play of this variety of living things, but how far more absorbing and inexhaustible does the delight become when we feel that in studying this universal play of life we are every moment probing the depths of our own souls.