Page:Popular Science Monthly Volume 40.djvu/285

Rh scientific man, on the other hand, recognizes an external world and positive knowledge, and seeks to contribute some new grain of truth if he may. He observes, hypothesizes, and verifies, and finally submits his result to verification by the race, the ultimate criterion being the unanimous consensus of the competent.

Notwithstanding Dr. Abbot's clear statement of the scientific method, this final standard of knowledge seems ambiguous. The truth of a theory needs no further test than its complete verification by all the facts to which it applies.

To make a synopsis of the Synthetic Philosophy of Herbert Spencer intelligible within the limits of a lecture is a difficult task, which Mr. B. F. Underwood has accomplished extremely well. Not only this, but he has given an introductory analysis of the opposing philosophical systems which preceded the evolution hypothesis. The sensation philosophy of Locke and Hume, and the a priori speculations of Kant, representing hoary antagonisms of thought, were by Spencer's insight found to be different halves of the whole truth that knowledge is derived from experience, but the experience of the race furnishes innate ideas to the individual. Spencer's doctrine that we perceive only phenomena, and from these infer the noumenal existence which causes changes in consciousness, is known as transfigured realism; and, though charged with idealistic leaning by rank realists, is no more transcendental than the views of Dr. Maudsley and Prof. Huxley. According to the latter, "all phenomena are, in their ultimate analysis, known to us only as facts of consciousness." But it is the "unknowable reality" which proves a stumbling-block to many. Theologians dislike this, since it excludes a knowledge of God, and the scientific are afraid cf it because Unknowable is printed with a capital, which suggests another sort of deity. Disciples of Haeckel vainly impute dualism to Mr. Spencer, while he declares, "I recognize no forces within the organism or without the organism but the variously conditional modes of the universal immanent force." Whatever chiseling time may effect in the body of Spencer's doctrine, there is good reason to believe with Mr. Underwood that the leading principles will remain intact.

In the Evolution of Chemistry, Dr. R. G. Eccles has skillfully traced the growth of chemical knowledge from the vague theories of the ancients to the definite, complex science of to-day. After the time of Aristotle the elemental theory or doctrine of abstract qualities saturated thought for fifteen hundred years. The scales first used by the young Scotch chemist Black weighed scholastic dogma as well as fixed air, and proved the hollowness of a priori reasoning. This step in verification made progress possible. Oxygen was discovered by Priestley, combustion explained by Lavoisier, and the law of definite and multiple proportions ascertained by Dalton. The idea of continuous matter was displaced by the atomic theory, and Avogadro's law regarding the volume of gases confirmed the hypothesis. The laws of specific heat, crystallography, and Mendelejeff's formula, each added its proof of atomic weight. The study of the coherence of groups of atoms resulted in the wonderful synthetic productions of the laboratory. The brilliant dyes, flavorings, perfumes, and medicines made by the chemist excelled those offered by Nature, and utilized hitherto waste products. Although the detail of organic chemistry is now beyond the mastery of any man, the outlook is infinite, and problems whose solution promises the secret of creation itself tempt the student. The composition of the ferments, pepsin and trypsin, or of the albuminoids, and the conversion of starch into cane sugar, would unlock incalculable benefits. The author considers the development of chemical knowledge, like the habits of atoms, closely illustrative of evolutionary law.

Thales suggested electricity as a condition of life, and the author of The Evolution of Electric and Magnetic Physics is inclined to agree with him. According to Mr. Kennelly, "it is possible, if it is not at present demonstrated, that electricity may be the active principle in the processes of animal vitality; . . . the relation between electricity and vitality may be so close as to amount to identity." This is perhaps pardonable in the chief electrician of Edison's laboratory, but it is-doubtful if any eminent physiologist or psychologist will allow that nerve-fibers do more than artificially