PLATO’S SURVEY OF THE SCIENCES.
Plato, like Francis Bacon, took a review of the sciences of his time: he enumerates arithmetic and plane geometry, treated as collections of abstract and permanent truths; solid geometry, which he “notes as deficient” in his time, although in fact he and his school were in possession of the doctrine of the “five regular solids;” astronomy, in which he demands a science which should be elevated above the mere knowledge of phenomena. The visible appearances of the heavens only suggest the problems with which true astronomy deals; as beautiful geometrical diagrams do not prove, but only suggest geometrical propositions. Finally, Plato notices the subject of harmonics, in which he requires a science which shall deal with truths more exact than the ear can establish, as in astronomy he requires truths more exact than the eye can assure us of.
In a subsequent paper Plato speaks of Dialectic as a still higher element of a philosophical education, fitted to lead men to the knowledge of real existences and of the supreme good. Here he describes dialectic by its objects and purpose. In other places dialectic is spoken of as a method or process of analysis; as in the Phædrus, where Socrates describes a good dialectician as one who can divide a subject according to its natural members, and not miss the joint, like a bad carver. Xenophon says that Socrates derived dialectic from a term implying to divide a subject into parts, which Mr. Grote thinks unsatisfactory as an etymology, but which has indicated a practical connection in the Socratic school. The result seems to be that Plato did not establish any method of analysis of a subject as his dialectic; but he conceived that the analytical habits formed by the comprehensive study of the exact sciences, and sharpened by the practice of dialogue, would lead his students to the knowledge of first principles.—Dr. Whewell.
FOLLY OF ATHEISM.
Morphology, in natural science, teaches us that the whole animal and vegetable creation is formed upon certain fundamental types and patterns, which can be traced under various modifications and transformations through all the rich variety of things apparently of most dissimilar build. But here and there a scientific person takes it into his foolish head that there may be a set of moulds without a moulder, a calculated gradation of forms without a calculator, an ordered world without an ordering God. Now, this atheistical science conveys about as much meaning as suicidal life: for science is possible only where there are ideas, and ideas are only possible where there is mind, and minds are the offspring of God; and atheism itself is not merely ignorance and stupidity,—it is the purely nonsensical and the unintelligible.—Professor Blackie; Edinburgh Essays, 1856.
THE ART OF OBSERVATION.
To observe properly in the very simplest of the physical sciences requires a long and severe training. No one knows this so feelingly as the great discoverer. Faraday once said, that he always doubts his own observations. Mitscherlich on one occasion remarked to a man of science that it takes fourteen years to discover and establish a single new fact in chemistry. An enthusiastic student one day betook himself to Baron Cuvier with the exhibition of a new organ—a muscle which he supposed himself to have discovered in the body of some living creature or other; but the experienced and sagacious naturalist kindly bade the young man return to him with the same discovery in six months. The Baron would not even listen to the student’s demonstration, nor examine his dissection, till the eager and youthful discoverer had hung over the object of inquiry for half a year; and yet that object was a mere thing of the senses.—North-British Review, No. 18.
MUTUAL RELATIONS OF PHENOMENA.
In the observation of a phenomenon which at first sight appears to be wholly isolated, how often may be concealed the germ of a great discovery! Thus, when Galvani first stimulated the nervous fibre of the frog by the accidental contact of two heterogeneous metals, his contemporaries could never have anticipated that the action of the voltaic pile would discover to us in the alkalies metals of a silver lustre, so light as to swim on water, and eminently inflammable; or that it would become a powerful instrument of chemical analysis, and at the same time a thermoscope and a magnet. When Huyghens first observed, in 1678, the phenomenon of the polarisation of light, exhibited in the difference between two rays into which a pencil of light divides itself in passing through a doubly refracting crystal, it could not have been foreseen that a century and a half later the great philosopher Arago would, by his discovery of chromatic polarisation, be led to discern, by means of a small fragment of Iceland spar, whether solar light emanates from a solid body or a gaseous covering; or whether comets transmit light directly, or merely by reflection.—Humboldt’s Cosmos, vol. i.