On the contrary, he would gladly see in every town a fine church dedicated to the men and women of genius who with great mother-ideas have tried to better the strife of human adventure. For two reasons I used the phrase “have tried to better.” In the first place, the constituents of new knowledge, when mingled with the old customs and conventions, lose much of their good invariably; and, next, the amalgam thus formed may become explosive. At this moment we see in our new art, the art of flying, how precarious is the charity that mother-ideas bring into the battlefields of competition. What aeroplanes can do in war is already the only consideration that the mother-idea of mechanical flight receives from the most alert minds; and very soon military engineers will be called upon to invent bomb-proof covers for every strategic bridge which cannot be displaced by a tunnel. So we compel airmanship to torment us with visions of wrecked cities, when she ought to delight us with bird’s-eye views of happier countries. In brief, the more we study mother-ideas the more clearly we perceive that they in themselves are phases of strife, for they have power to do harm as well as good. Providence for ever tries to quicken the inept human mind, since no blessing is granted to us without its attendant bane. Electricity has dangers of its own, so has fire; Pasteurism has dangers of its own, so has food; radium is curative and very perilous, like the sea or the sun; and all other good things ask us to pick our way with care between danger and utility.