mention of the relation of his philosophical views to those of other writers. He does not give us his bearings, so to speak, but leaves us to discover them for ourselves. We can not think this policy a good one. To the general reader it is not helpful, as it may lead him to form an exaggerated idea of the originality of the views contained in the volume—a result, we are sure, at which the author would not consciously aim. Some special illustrations of what we are now remarking upon may present themselves before we close.
"All metaphysical or ontological speculation is based upon a disregard of some or all of the truths above set forth. Metaphysical thinking is an attempt to deduce the true nature of things from our concepts of them." The last sentence presents us with a definition of admirable terseness and force, stating as it does the whole case against metaphysics in a dozen words. For purposes of thought we analyze and abstract; but, not content with deriving from these operations the logical aid they are calculated to afford, we fly off to the conclusion that what we have done in the realm of thought holds good outside of thought or absolutely. To apply this to the matter in hand: where the "mechanical theory of the universe" asserts mass and motion to be the "absolutely real and indestructible elements of all physical existence," it overlooks the fact that mass and motion by themselves are really elements of nothing but thought, and are simply a kind of mental residuum after all the more special properties of objects have, by successively wider generalizations (as before explained), been mentally abstracted. As our author puts it: "They are ultimate products of generalization, the intellectual vanishing-points of the lines of abstraction which proceed from the infimæ species of sensible experience. Matter is the summum genus of the classification of bodies on the basis of their physical and chemical properties. Of this concept, matter, mass and motion are the inseparable constituents. The mechanical theory, therefore, takes not only the ideal concept matter, but its two inseparable constituent attributes, and assumes each of them to be a distinct and real entity." Mr. Stallo sees in this a survival of mediæval realism; but it is really nothing else than the opinion of the multitude, now and in all ages, elevated to the rank of a philosophical doctrine. Men in general are materialists who temper their materialism to themselves by a supplementary belief in spiritual existences.
Not only is the mind prone to believe that its concepts are truly representative of external realities, but it readily assumes also that the order of succession in the world of thought must be the order of development in the external world. The effect of the latter illusion is completely to invert the order of reality. "The summa genera of abstraction—the highest concepts—are deemed the most, and the data of sensible experience the least, real of all forms of existence." Because we arrive at the concept matter by leaving out of consideration all the properties that differentiate one form of matter from another,
