The accessions of knowledge which have come in the course of our philosophy have been nothing in themselves: they always stand in the service of one world-view or the other, and attain only in it to their real significance. But the characteristic thing about the way in which the settlement is made on each occasion, is that it never is made openly. The two world-views are never brought face to face and the case of each heard. That the optimistic alone is in the right is a conviction which is accepted as more or less self-evident. The only thing felt as a problem is how to marshal all possible knowledge in the triumphal procession of proof to defeat the other, and to knock on the head anything that may still wish to rise in its defence. [pg 013] Since the pessimistic world-view has never made its presence properly felt, Western thought manifests a lofty unwillingness to understand it, though it has a splendid faculty for detecting it. Where it finds, as in Spinoza, too little interest for activity directed upon the world, it reacts immediately with rejection of it. Yet all objectively thinking investigation of the reality of nature is disliked by it because it may lead to the central position of the human spirit in the world being insufficiently emphasised. It is because materialism seems likely to be the last ally of pessimism that it carries on so embittered a struggle against it. In the discussion of the problem of the theory of knowledge from Descartes to Kant and beyond him it is really the cause of the optimistic world-view which is being maintained. That is why the theoretical possibility of a depreciation or a denial of the world of sense is attacked with such obstinacy. By proving the ideality of space and time Kant hopes to make finally secure the optimistic world-view of rationalism with all its ideals and demands. Only so can it be explained that the most acute examinations of the theory of knowledge are carried through with the most naïve conclusions about world-view. The great post-Kantian systems of thought, however much they differ from one another in their subject-matter and the process of the speculation with which they deal with it, are all united in this, that they crown the optimistic world-view in their cloud-castles as the ruler of the universe. To fit in the aims of mankind with those of the universe in a logically convincing fashion, that is the endeavour in which European philosophy serves the optimistic world-view. Anyone who does not help, or who is indifferent about it, is an enemy.