Religion comes into contact with naturalism and demands to be reconciled with it, not merely at its periphery, but at its very core, namely, with its characteristic ideal of a mathematical-mechanical interpretation of the whole world. This ideal seems to be most nearly, if not indeed completely, attained in reference to the inter-relations of the great masses, in the realm of astronomy, with the calculable, inviolable, and entirely comprehensible conditions which govern the purely mechanical correlations of the heavenly bodies. To bring the same clearness and intelligibility, the same inevitableness and calculability into the world in general, and into the whole realm of nature down to the mysterious law determining the development of the daintiest insect’s wing, and the stirrings of the grey matter in the cortex of the brain which reveal themselves to us as sensation, desire, and thought, this has always been the aim and secret faith of the naturalistic mode of thought. It is thus aiming at a Cosmos of all Being and Becoming, which can be explained from itself, and comprehended in itself alone, supported by its own complete and all-sufficing causality and uniformity, resting in itself, shut up within itself, complete in itself—a God sufficient unto himself and resting in himself. We do not need to probe very deeply to find out how strongly religion resists this attempt, and we easily discover what is the disturbing element which awakens hostile feeling. It is of three kinds, and depends on three characteristic aims and requirements of religion, which are closely associated with one another, yet distinct from one another, though it is not always easy to represent them in their true proportions and relative values. The first of these interests seems to be “teleology,” the search after guiding ideas and purposes, after plan and directive control in the whole machinery, that sets itself in sharp opposition to a mere inquiry into proximate causes. Little or nothing is gained by knowing how everything came about or must have come about; all interest lies in the fact that everything has come about in such a way that it reveals intention, wisdom, providence, and eternal meaning, realising itself in details and in the whole. This has always been rightly regarded as the true concern and interest of every religious conception of the world. But it has been sometimes forgotten that this is by no means the only, or even the primary interest that religion has in world-lore. We call it its highest and ultimate interest, but we find, on careful study, that two others are associated with and precede it.