These convictions and their fundamental implications can be defined quite clearly, both singly and as a whole, and later we shall attempt so to define them. And it is of the greatest importance to religion that these presuppositions and postulates should have their legitimacy and validity vindicated. For they are at once the fundamental and the minimal postulates which religion must make in its outlook on the world, which it must make if it is to exist at all. And they are so constituted that, even when they are released from their primitive and naïve form and association, and permitted speculative development and freedom, they must, nevertheless, just because they contain a theory of the world, be brought into comparison, contact, or relation of some kind, whether hostile or friendly, with other world-conceptions of different origin. This relation will be hostile or friendly according to the form these other conceptions have taken. It is impossible to imagine any religious view of the world whose network of conceptions can have meshes so wide, or constituents so elastic and easily adjustable, that it will allow every theoretical conception of nature and the world to pass through it without violence or friction, offering to none either let or hindrance. It has indeed often been affirmed that religion may, without anxiety about itself, leave scientific knowledge of the world to go its own way. The secret reservation in this position is always the belief that scientific knowledge will never in any case reach the real depth and meaning of things. Perhaps this is true. But the assumption itself would remain, and would have to be justified. And if religion had no other interest in general world-theory, it would still have this pre-eminent one, that, by defining the limitations of scientific theory, and showing that they can never be transcended, it thus indicates for itself a position beyond them in which it can dwell securely. In reality religion has never ceased to turn its never-resting, often anxious gaze towards the progress, the changes, the secure results and tentative theories in the domain of general world-science, and again and again it has been forced to come to a new adjustment with them. One great centre of interest, though by no means the only or even the chief one, lies in the special field of world-lore and theoretical interpretation comprised in the natural sciences. And in the following pages we shall make this our special interest, and shall endeavour to inquire whether our modern natural science consists with the “minimal requirements” of the religious point of view, with which we shall make closer acquaintance later; or whether it is at all capable of being brought into friendly relations with that point of view.