ACCORDING to Plato's famous myth, two gifts of the gods equipped man for living: the one, arts and inventions to supply him with the means of livelihood; the other, reverence and justice to be the ordering principles of societies and the bonds of friendship and conciliation. Agencies for mastery over nature and agencies for cooperation among men remain the two great sources of human power. But after two thousand years, it is possible to note an interesting fact as to their relative order of development in civilization. Nearly all the great skills and inventions that had been acquired up to...