over the notion of progress from Saint-Simon. This was Comte, whose attitude to progress in many respects resembles that of Saint-Simon, but he brought to his work a mental equipment lacking in the earlier writer and succeeded, by the position he gave to it in his Positive Philosophy, in making the idea of progress one which subsequent thinkers could not omit from consideration. According to Comte, the central factor in progress is the mental. Ideas, as Fouillée was later to assert, are the real forces in humanity’s history. These ideas develop in accordance with the “Law of the Three Stages,” already explained in our Introduction. In spite of the apparent clearness and simplicity of this law, Comte had to admit that as a general law of all development it was to some degree rendered difficult in its application by the lack of simultaneity in development in the different spheres of knowledge and social life. While recognising the mental as the keynote to progress, he also insisted upon the solidarity of the physical, intellectual, moral and social life of man, and to this extent admitted a connection and interaction between material welfare and intellectual progress. The importance of this admission lay in the fact that it led Comte to qualify what first appears as a definite and confident belief in a rectilineal progress. He admits that such a conception is not true, for there is retrogression, conflict, wavering, and not a steady development. Yet he claims that there is a general and ultimate progress about a mean line. The causes which shake and retard the steady progress are not all-powerful, they cannot upset the fundamental order of development. These causes which do give rise to variations are, we may note in passing, the effects of race, climate and political and military feats like those of Napoleon, for whom Comte did not disguise his hatred, styling him the man who had done most harm to humanity. Great men upset his sociological theories, but Comte was no democrat and strongly opposed ideas of Liberty and Equality. We have remarked upon his general attitude to his own age, as one of criticism and anarchy. In this he was probably correct, but he quite underestimated the extent and duration of that anarchy, particularly by his estimate of the decline and fall of Catholicism and of militarism, which he regarded as the two evils of Europe. The events of the twentieth century would have been a rude shock to him, particularly the international conflagration of 1914-1918. It was to Europe that Comte confined his philosophy of history and consequently narrowed it. He knew little outside this field.