Religion and Science from Galileo to Bergson

by J. C. Hardwick

The New Philosophy.—The task, however, of constructing a new philosophy of the universe was courageously taken in hand by a succession of thinkers, and the energy of thought which the great problem generated is characteristic of perhaps the most vigorous century of European history—the seventeenth.

The tendency of the new discoveries in science had not been obscure, and Modern Philosophy starts with an attempt to represent the universe as a self-working machine—a co-ordinated whole, throughout which the principles of mathematics are universally valid. The trend of ideas set in motion by the new discoveries in astronomy seemed to point in this direction. But to introduce mechanics into the celestial regions, though an important step, was but a beginning. Mechanics must be universally valid—even in the human body—or the new teaching was vain. Exceptions may prove a rule, but they destroy a philosophy.

The Subjugation of Physiology.—It was an Englishman who provided the necessary facts to fill the gravest gap in the mechanical theory. It was already known in the previous century that the blood of animals circulated throughout the body; the existence and use of veins and heart-valves was also known, but it was William Harvey (1578-1657) who discovered the heart to be the organ responsible for maintaining the circulation of the blood, by purely mechanical means. This was a fact of the utmost significance. In the sphere of physiology, where theories about mysterious powers of blood or soul had been hitherto authoritative, it effected a revolution. Indeed it is true to say that Harvey "is to physiology what Galileo was to physics." He proved that "the general laws of motion are valid within as well as without the organism"—an important extension of the mechanical theory.

Descartes.—Among the leading men who accepted Harvey's theory, one of the first was René Descartes (1596-1650). Well might this thinker welcome it, for it was a most important contribution to the imposing philosophic fabric for which he was industriously collecting materials. Descartes, apart from his philosophical speculations, is an interesting character, being a Frenchman of noble birth who was educated by the Jesuits, saw something of contemporary life in Paris, served as a military officer in Holland and Germany, and made some original discoveries in mathematics.

The mathematical mind, accustomed as it is to deal with highly abstract ideas, takes kindly to metaphysics. And it very often solves the mystery of the universe by expressing all its contents in mathematical terms. Such, at least, was Descartes' method. The simplest and clearest ideas which we can have of anything are mathematical, i.e. extension and mobility. And it is by concentrating our attention upon this simple and mathematical aspect of things that we shall arrive at a proper understanding of all that goes on in the material world.

Universality of Mathematics.—A phenomenon was, in Descartes' eyes, "explained" only when a "cause" which is its exact mathematical equivalent, has been indicated. The "cause" and the "effect" are two sides of a mathematical equation (Causa aequat effectum). Anything that happens in the material world (the fall of a stone, the beat of a heart, the rising of the sun) is really nothing more than a redistribution of portions of that sum of motion which, once generated at the Creation, has remained unaltered, and unalterable, in the universe ever since. The sum of motion is constant, there can be no addition to or subtraction from it. In this sense it would be true that "there is nothing new under the sun": only ever-new distributions of the old.

The Universe a Machine.—Once assume that all phenomena can be interpreted in terms of motion, and add the proposition (already enunciated by Galileo) that motion once set going will proceed for ever, unless some impediment from outside intervenes, and the mechanical view of the universe is complete. The universe is a machine, i.e. a thing that works (1) according to mathematical principles, (2) automatically.

Elaborations of the Mechanical Theory.—The importance of Descartes lies not in his having invented this conception (we have already seen it in the hands of Leonardo da Vinci, Galileo, and others), but in his having elaborated it. This he did in two directions: (1) he attempted to supply a mechanical theory of the evolution of the world-system; i.e. to show how the heavenly bodies came into being by natural and mechanical processes; (2) he applied the mechanical theory to organisms; animals and men were complex machines. (Here, as we have seen, the discovery of Harvey was of prime importance.)

It is hardly necessary to describe at length Descartes' mechanical theory of the evolution of the world-system, though an interest attaches to it as being the ancestor of the modern "nebular hypothesis." Matter in whirling motion around fixed centres is the original datum from which Descartes evokes the universe. With regard to the mechanical theory of organisms, Descartes developed it at some length in various treatises. All the functions and actions of animals were regarded by him as entirely involuntary and mechanical. "That the lamb flees at the sight of a wolf happens because the rays of light from the body of the wolf strike the eye of the lamb, and set the muscles in motion by means of the 'reflex' currents of the animal spirits."

In the case of human beings, owing to the phenomenon of "consciousness," Descartes felt compelled to assume a "soul"—a thinking substance in reciprocal action with the material substance (of the brain). This, too, is an anticipation of the modern theory of "psycho-physical parallelism."