Though we find here some unwarranted assumptions, as well as some grave omissions, yet this part (Laws of the Knowable) may be considered, upon the whole, as a fine specimen of scientific reasoning. Considerable space is devoted to the "Law of Evolution" the discovery of which is the author's chief claim to originality, and certainly evinces great power of generalization. To quote the abstract definition without a full statement of the inductions from which it is derived would convey no fair impression of the breadth and strength of the thought which it epitomizes. Of Mr. Spencer's general characteristics as a writer, we may observe that his style is marked by great purity, clearness, and force; though it is somewhat diffuse, and the abstract nature of some of his topics occasionally renders his thought difficult of apprehension. His treatment of his subjects is generally thorough and sometimes exhaustive; his arguments are always ingenious if not always convincing; his illustrations are drawn from almost every accessible field of human knowledge, and his method of "putting things" is such as to make the most of his materials. He is undoubtedly entitled to a high rank among the speculative and philosophic writers of the present day.... In Mr. Spencer we have the example of a positivist, who does not treat the subject of religion with supercilious neglect, and who illustrates by his own method of reasoning upon the highest objects of human thought, the value of those metaphysical studies which it is so much the fashion of his school to decry. For both these reasons the volume, which we now propose to examine, deserves the careful attention of the theologian who desires to know what one of the strongest thinkers of his school, commonly thought atheistic in its tendencies, can say in behalf of our ultimate religious ideas. For if we mistake not, in spite of the very negative character of his own results, he has furnished some strong arguments for the doctrine of a positive Christian theology. We shall be mistaken if we expect to find him carelessly passing these matters by (religious faith and theological science) as in all respects beyond knowledge and of no practical concern. On the contrary, he gives them profound attention, and arrives at conclusions in regard to them which even the Christian theologian must allow to contain a large measure of truth. While showing the _unsearchable nature_ of the ultimate facts on which religion depends, he demonstrates their _real existence_ and their great importance.... In answering these questions Mr. Spencer has, we think, arrived nearer to a true philosophy than either Hamilton or Mansel. At least he has indicated in a more satisfactory manner than they have done, the positive datum of consciousness that the unconditioned, though inscrutable, _exists_. It may be said that Mr. Spencer is not chargeable with excluding God from the universe, or denying all