Buckle was the great advocate of the primacy of intellectual development in the sense of increase of natural knowledge. The argument by which he sought to establish the position runs as follows: Progress must have been due to improvement either of moral or of intellectual principles. But moral principles have been almost the same in all ages. “To do good to others; to love your neighbour as yourself; to honour your parents—these and a few others, are the sole essentials of morals; but they have been known for thousands of years, and not one jot or tittle has been added to them by all the sermons, homilies and text-books which moralists and theologians have been able to produce.” On the other hand, knowledge and intellectual principles have made immense strides; hence all progress must have been primarily intellectual rather than moral. Buckle did not deny that there has been some moral progress; rather he insisted upon it as an essential feature of the progress of civilisation; but it has, according to him, consisted only in the more effective operation of unchanging principles, and this more effective operation is secondary to, and due to, intellectual progress. I think we must agree with Buckle that the increasing store of knowledge and the increased command over nature that comes with it has been the primary condition of the progress of nations. For, since the early middle ages, the moral natures of men and the teaching of Christianity have been the same in all essentials; yet for many centuries there was practically no progress. Kidd himself admitted that progress only set in rapidly about the time of the Reformation. And it is notorious that this progress, including the Reformation itself, was due to the stimulation of the intellect by a number of influences—by the renewed study of classical art and literature, by the discovery of the New World, by the increased intercourse of nations resulting from the improvement of the art of navigation, by the accumulation of wealth and the formation of a powerful middle class. It is clear also that religion, far from having been the sufficient cause or instrument of progress, was largely responsible for the stagnation of the middle ages, through sternly repressing the sceptical spirit and leading off men’s minds from inquiry into natural laws, to the discussion of many topics on which it was impossible to achieve knowledge and which were necessarily barren of results making for human progress. Nevertheless the Christian religion has in the long run co-operated in forwarding the mental evolution of the European peoples in an important manner which we must briefly consider later—namely, through its effects upon social organisation.