Page:Popular Science Monthly Volume 5.djvu/439

Rh mind there exists a unity of composition; and the doctrines of innate ideas, intuitions by gift of God, supernatural revelations, mysticism of all kinds, have the ground cut from under them.

The very great extension of plan which Mr. Spencer's work received between 1855 and 1870-'72 was due solely to the creation of his own philosophy of evolution. That in its turn had its initiative in the theory of the correlation of forces advanced by Grove in 1842. As the new philosophy conceived all existence to result from evolution through differentiation and integration, it was incumbent on Mr. Spencer to show that mental phenomena, or at least the physical correlatives of them, can be interpreted in terms of the redistribution of matter and motion, and explained by a series of deductions from the persistence of force. This is the task of a Physical Synthesis, which shows the structure and functions of the nervous system to have resulted from intercourse between the organism and its environment. And thus is laid the coping-stone of a treatise which has definitively constituted Psychology a science.

With the definitive constitution of the science our inquiry, which began with the differentiation of its subject-matter, comes to an end. We have seen mind slowly emancipating itself from the barbaric Cosmos, and raised into an independent object of speculation. Once "differentiated" it begins itself to unfold, and at the same time to gather round it the at first alien facts of sensation, appetite, and bodily feeling generally. These are increasingly matter of inquiry, and theories respecting them take the hue and shape of the sciences which relate to the material world. The science of motion evolves, and the idea of orderly sequence enters into Psychology. Natural Philosophy rises from motion to force, and Psychology passes from conjunction to causation. Chemistry tears aside a corner of Nature's veil, and a shaft is sunk in a mysterious field of mind. The sciences of organic nature receive a forward impulse, and mind and life are joined in inextricable union. A philosophy of the universe, incorporating all the sciences, is created, and Psychology, while attaining increased independence as regards the adjacent sciences, is merged in that deductive science of the Knowable which has more widely divorced, and yet more intimately united, the laws of matter and of mind.—Westminster Review.



INCE the beginning of this century, our idea of the universe has undergone a complete metamorphosis, though but few persons appear to recognize this fact. Less than a century ago, the savants who admitted the earth's motion (some still rejected it) pictured to 