This distrust of the physical forces, or our disbelief in their ability to give rise to life, is like a survival in us of the Calvinistic creed of our fathers. The world of inert matter is dead in trespasses and sin and must be born again before it can enter the kingdom of the organic. We must supplement the natural forces with the spiritual, or the supernatural, to get life. The common or carnal nature, like the natural man, must be converted, breathed upon by the non-natural or divine, before it can rise to the plane of life—the doctrine of Paul carried into the processes of nature.
The scientific mind sees in nature an infinitely complex mechanism directed to no special human ends, but working towards universal ends. It sees in the human body an infinite number of cell units building up tissues and organs,—muscles, nerves, bones, cartilage,—a living machine of infinite complexity; but what shapes and coördinates the parts, how the cells arose, how consciousness arose, how the mind is related to the body, how or why the body acts as a unit—on these questions science can throw no light. With all its mastery of the laws of heredity, of cytology, and of embryology, it cannot tell why a man is a man, and a dog is a dog. No cell-analysis will give the secret; no chemical conjuring with the elements will reveal why in the one case they build up a head of cabbage, and in the other a head of Plato.
It must be admitted that the scientific conception of the universe robs us of something—it is hard to say just what—that we do not willingly part with; yet who can divest himself of this conception? And the scientific conception of the nature of life, hard and unfamiliar as it may seem in its mere terms, is difficult to get away from. Life must arise through the play and transformations of matter and energy that are taking place all around us; though it seems a long and impossible road from mere chemistry to the body and soul of man. But if life, with all that has come out of it, did not come by way of matter and energy, by what way did it come? Must we have recourse to the so-called supernatural?—as Emerson's line puts it,—
"When half-gods go, the gods arrive."
When our traditional conception of matter as essentially vulgar and obstructive and the enemy of the spirit gives place to the new scientific conception of it as at bottom electrical and all-potent, we may find the poet's great line come true, and that for a thing to be natural, is to be divine. For my own part, I do not see how we can get intelligence out of matter unless we postulate intelligence in matter. Any system of philosophy that sees in the organic world only a fortuitous concourse of chemical atoms, repels me, though the contradiction here implied is not easily cleared up. The theory of life as a chemical reaction and nothing more does not interest me, but I am attracted by that conception of life which, while binding it to the material order, sees in the organic more than the physics and chemistry of the inorganic—call it whatever name you will—vitalism, idealism, or dualism.
In our religious moods, we may speak, as Theodore Parker did, of the universe as a "handful of dust which God enchants," or we may speak of it, as Goethe did, as "the living garment of God"; but as men of science we can see it only as a vast complex of forces, out of which man has arisen, and of which he forms a part. We are not to forget that we are a part of it, and that the more we magnify ourselves, the more we magnify it; that its glory is our glory, and our glory its glory, because we are its children. In some way utterly beyond the reach of science to explain, or of philosophy to confirm, we have come out of it, and all we are or can be, is, or has been, potential in it.
IX
The evolution of life is, of course, bound up with the evolution of the world. As the globe has ripened and matured, life has matured; higher and higher forms—forms with larger and larger brains and more and more complex nerve mechanisms—have appeared.
Physicists teach us that the evolution of the primary elements—hydrogen, oxygen, nitrogen, carbon, calcium, and the like—takes place in a solar body as the body cools. As temperature decreases, one after another of the chemical elements makes its appearance, the simpler elements appearing first, and the more complex compounds appearing last, all apparently having their origin in some simple parent element. It appears as if the evolution of life upon the globe had followed the same law and had waited upon the secular cooling of the earth.
Does not a man imply a cooler planet and a greater depth and refinement of soil than a dinosaur? Only after a certain housecleaning and purification of the elements do higher forms appear; the vast accumulation of Silurian limestone must have hastened the age of fishes. The age of reptiles waited for the clearing of the air of the burden of carbon dioxide. The age of mammals awaited the deepening and the enrichment of the soil and the stability of the earth's crust. Who knows upon what physical conditions of the earth's elements the brain of man was dependent? Its highest development has certainly taken place in a temperate climate. There can be little doubt that beyond a certain point the running-down of the earth-temperature will result in a running-down of life till it finally goes out. Life is confined to a very narrow range of temperature. If we were to translate degrees into miles and represent the temperature of the hottest stars, which is put at 30,000 degrees, by a line 30,000 miles long, then the part of the line marking the limits of life would be approximately three hundred miles.