It should be added that he was greatly averse to every form of militant anti-religious controversy, and always deprecated it. He would have been the last to desire that his words should be quoted as of scientific authority, or as being more than the results of his own thought on questions which were not the subject of his life study. Let those who think that his having expressed these views is a regrettable blow to orthodox Christianity, set against it the enormous service Darwin did to reasonable natural theology by giving an intelligible key to the explanation of the universe. And let all men remember that genuine honesty such as Darwin's cannot possibly hinder the interests or the spread of truth. His declaration that "man can do his duty," implies his conviction that man may know what his duty is; and very many noble spirits besides Darwin have not found it possible to advance with certainty beyond this point. As to Darwin's place in literature, that is due supereminently to his thoughts. In his expression of them he had the saving quality of directness, and usually wrote with simplicity. Incisive he was not ordinarily; caution of his type harmonises ill with incisiveness. But what he lost thereby he gained in solidity and in permanence. Sometimes, as we have pointed out, his imagination carried him beyond his usual sober vein, and then he showed himself aglow with feeling or with sympathetic perception. But when we speak of his imagination we pass at once to the other side of his mind--if indeed any such patient inquiry as his could have been maintained except for the imaginative side of him. This lit up his path, buoyed him in difficulties and failures, suggested new expedients, experiments, and combinations. The use of imagination in science has never been more aptly illustrated nor more beneficial than in his case. Darwin, more than any other man perhaps, showed the value, if not the essentiality, of "working hypotheses"; and if any man now wants to progress in biology, he will be foolish if he does not seek such and use them freely, and abandon them readily if disproved.