Though the fault has not always been on the side of the scientists: "Metaphysics itself, by its interference with physical science, has induced that to act, as it thinks, in self-defence, and has led it, in so doing, to become metaphysical. And this interference of metaphysics I would admit and deplore, as the result and the parent of most injurious misunderstanding.... So long as natural science keeps merely to the sphere of phenomena and the laws of their occurrence, metaphysics has no right to a single word of criticism" (p. 285). This critical handling of the problem of the relations of science and philosophy did much to draw attention to the confusion of thought lying at the base of much popular materialism. It began to be realised that the principles of physical science are only fruitful of good results in the sphere properly belonging to them; and that the uncritical use of these principles results in a hybrid philosophy, which is neither sound science nor rational metaphysics. A. J. BALFOUR.--Before Bradley's essay was published, a somewhat similar line of criticism had been developed by Mr. A. J. Balfour in his _Defence of Philosophic Doubt_ (1879). Its title sounds unpromising, but the book voiced a demand for a rational philosophy of science which was practically non-existent at that time; and consequently, in the absence of any adequate examination of the principles of science, uncritical dogmatism flourished quite unchallenged. Balfour, elsewhere, indicates the objects with which he wrote the book--to elicit from the disciples of natural science a _rationale_ of their method: "A full and systematic attempt, first to enumerate, and then to justify, the presuppositions on which all science finally rests, has, it seems to me, still to be made. After the critical examination which I desiderate has been thoroughly carried out, it may appear that at the very root of our scientific system of belief lie problems of which no satisfactory solution has yet been devised."[49] Thus Balfour drew attention to the fact that the common-sense philosophy of naturalism rested upon a tacit agreement to overlook certain important problems which are the indispensable preliminaries to any thinking which can be called critical, or lay claim to be regarded as philosophy in the strict sense. That some of these problems seem artificial, and the questions raised by them gratuitous, to the eye of "common sense" is an irrelevant consideration, for "nothing stands more in need of demonstration than the obvious." NATURALISM CHECKED.--Thus Bradley and Balfour between them, merely by adopting a critical attitude, created an embarrassing situation for naturalism. Between them these writers administered a serious check to that naively uncritical dogmatism which, backed by the prestige of natural science, had sought to impose itself on the world as a new orthodoxy less liberal, in some ways, than the old.