If life can finally be explained in terms of physics and chemistry, that is, if the beginning of life on the globe was no new thing, the introduction of no new principle, but only the result of a vastly more complex and intimate play and interaction of the old physico-chemical forces of the inorganic world, then the gulf that is supposed to separate the two worlds of living and non-living matter virtually disappears: the two worlds meet and fuse. We shall probably in time have to come to accept this view—the view of the mechanico-chemical theory of life. It is in a line with the whole revelation of science, so far—the getting rid of the miraculous, the unknowable, the transcendentand find, and the enhancing of the potency the mystery of thing snear at hand we have always known in other for it is at first an unpalatable truth, like the discovery of the animal origin of man, or that consciousness and all our thoughts and aspirations are the result of molecular action in the brain; or like the experience of the child when it discsovers that its father or mother is the Santa Claus that filled its stockings. Science is constantly bringing us back to earth as to the ground underfoot. Our dream of something far-off, supernatural, vanishes. We lose the God of a far-off heaven and find a God in the common, the near always present, always active, always creating the world anew. Science thus corrects our delusions and vague superstitions, and brings us back near horn for the key we had sought afar. We shall probably be brought, sooner or later, to accept another unpalatable theory, that of the physical origin of the soul, that it is not of celestial birth except as the celestial and terrestrial are one. This is really only taking our religious teachers at their word, that God is here, as constant and as active in the commonest substance l know as in the highest heaven. Science finds the beginning of something like conscious intelligence in the first unicellular life, the first protozoön. When two more cells unite to form a metazoön, it finds a higher and more complex form of intelligence. In the brain of man, it finds a confraternity of millions of simple cells, each with a life and intelligence of its own, but when united and cooperating, the intelligence of all pooled, as it were, we have the mind and personality of man as the result. This fact leaves no room for the notion that the mind or soul is an entity apart from the organ which it uses. It seems, on the contrary, in some mysterious way, to be the result of the multicellular life of the nervous system. Thus we do not banish the mystery of the soul, we only bring it nearer home. We disprove a fable and are then confounded by the fact that lurks under it. And this proves true in all attempts at ultimate explanations of the phenomena of this world.
It seems as if we saw the hint of prophecy of the vegetable in the mineral—in this growth of crystals, in these arborescent forms of the frost on the pane or on the flagging-stones. One may see most wonderful tree and fern forms on the pavement, with clean open spaces between them, no less than in a wood—an endless variety of them. A French chemist has lately produced by inorganic compounds the growth of something like a plant, with roots, stem, branches, leaves, buds—a mineral plant, as if the type of the plant already existed in the soil. Yes, the inorganic is dreaming of the organic. And the plant in its cell structure, in its circulation, in its intelligence, or ingenious devices to get on in the world, is dreaming of the animal, and the animal is dreaming of the spiritual, and the spirituality of man touches the spirituality of the cosmos, and thus the circle is complete.
So far as science can find out, sentience is a property of matter which is evolved under certain conditions, and though science itself has not yet been able to reproduce these conditions, it still believes in the possibility. If life was not potential in the inorganic world, how is it possible to account for it? It is not a graft, it is more like a begetting. Nature does not work by prefixes and suffixes, but by unfolding and ever unfolding, or developing out of latent innate powers and possibilities—an inward necessity always working, but never an external maker. It is no help to fancy that life may have been brought to the earth by a falling meteorite from some other sphere. How did life originate upon that other sphere? It must have started here as surely as fire started here. We feign that Prometheus stole the first fire from heaven, but it sleeps here all about us, and can be evoked any time and anywhere. It sleeps in all forms of force. A falling avalanche of rocks turns to flame; the meteor in the air becomes a torch; the thunderbolt is a huge spark. So life, no doubt, slept in the inorganic, and was started by the reverse of friction, namely, by brooding.
When the earth becomes lifeless again, as it surely must in time, then the cycle will be repeated, a collision will develop new energy, and new worlds, and out of this newness will again come life.
It is highly probable that a million years elapsed between the time when the ancestor of man began to assume human form and the dawn of history. Try to think of that time and of the struggle of this creature upward: of the pain, the suffering, the low bestial life, the warrings, the defeats, the slow, infinitely slow gains, of his deadly enemies in other animals, of the repeated changes of climate of the northern hemisphere from subtropical to subarctic—the land at one time for thousands of years buried beneath an ice sheet a mile or more thick, followed by a cycle of years of almost tropical warmth even in Greenland—and all of this before man had yet got off of "all fours," and stood upright, and began to make rude tools and rude shelters from the storms.
The Tertiary period, early in which the first rude ancestor of man seems to have appeared, is less than one week of the great geologic year of the earth's history—a week of about five days. These days the geologists have named Eocene, Oligocene, Miocene, Pliocene, and Pleistocene, each one of these days covering, no doubt, a million years or more. The ancestor of man probably took on something like human form on the third, or Miocene, day. The other and earlier fifty or more weeks of the great geologic year gradually saw the development of the simpler forms of life, till we reach the earliest mammals and reptiles in the Permian, about the forty-eighth or forty-ninth week of the great year. The laying down of the coal measures, Huxley thinks, must have taken six millions of years. Well, the Lord allowed himself enough time. Evidently he was in no hurry to see man cutting his fantastic tricks here upon the surface of the planet. A hundred million years, more or less what of it? Did the globe have to ripen all those cycles upon cycles, like the apple on the tree? to bask in the sidereal currents, work and ferment in the sea of the hypothetical ether, before the gross matter could evolve higher forms of life? Probably every unicellular organism that lived and died in the old seas helped prepare the way for man, contributed something to the fund of vital energy of the globe upon which man was finally to draw. How life has had to adjust itself to the great cosmic changes! The delays must have been incalculable. The periodic refrigeration of the northern hemisphere, which brought on the ice age several times during each one of the Eocene and Miocene days, must have delayed the development of life, as we know it, enormously.