IV
The lay mind can hardly appreciate the necessity under which the man of science feels to account for all the phenomena of life in terms of the natural order. To the scientist the universe is complete in itself. He can admit of no break or discontinuity anywhere. Threads of relation, visible and invisible,—chemical, mechanical, electric, magnetic, solar, lunar, stellar, geologic, biologic,—forming an intricate web of subtle forces and influences, bind all things, living and dead, into a cosmic unity. Creation is one, and that one is symbolized by the sphere which rests forever on itself, which is whole at every point, which holds all forms, which reconciles all contradictions, which has no beginning and no ending, which has no upper and no under, and all of whose lines are fluid and continuous. The disruptions and antagonisms which we fancy we see are only the result of our limited vision; nature is not at war with itself; there is no room or need for miracle; there is no outside to the universe, because there are no bounds to matter or spirit; all is inside; deep beneath deep, height above height, and this mystery and miracle that we call life must arise out of the natural order in the course of time as inevitably as the dew forms and the rain falls. When the rains and the dews and the snows cease to fall,—a time which science predicts,—then life, as we know it, must inevitably vanish from the earth. Human life is a physical phenomenon, and though it involves, as we believe, a psychic or non-physical principle, it is still not exempt from the operation of the universal physical laws. It came by them or through them, and it must go by them or through them.
The rigidly scientific mind, impressed with all these things as the lay mind cannot be, used to the searching laboratory methods, and familiar with the phenomenon of life in its very roots, as it were, dealing with the wonders of chemical compounds, and the forces that lurk in molecules and atoms, seeing in the cosmic universe, and in the evolution of the earth, only the operation of mechanical and chemical principles; seeing the irrefragable law of the correlation and the conservation of forces; tracing consciousness and all our changes in mental states to changes in the brain substance; drilled in methods of proof by experimentation; knowing that the same number of ultimate atoms may be so combined or married as to produce compounds that differ as radically as alcohol and ether,—conversant with all these things, and more, I say,—the strictly scientific mind falls naturally and inevitably into the mechanistic conception of all life phenomena.
Science traces the chain of cause and effect everywhere and finds no break. It follows down animal life till it merges in the vegetable, though it cannot put its finger or its microscope on the point where one ends and the other begins. It finds forms that partake of the characteristics of both. It is reasonable to expect that the vegetable merges into the mineral by the same insensible degrees, and that the one becomes the other without any real discontinuity. The change, if we may call it such, probably takes place in the interior world of matter among the primordial atoms, where only the imagination can penetrate. In that sleep of the ultimate corpuscle, what dreams may come, what miracles may be wrought, what transformations take place! When I try to think of life as a mode of motion in matter, I seem to see the particles in a mystic dance, a whirling maze of motions, the infinitely little people taking hold of hands, changing partners, facing this way and that, doing all sorts of impossible things, like jumping down one another's throats, or occupying one another's bodies, thrilled and vibrating at an inconceivable rate.
The theological solution of this problem of life fails more and more to satisfy thinking men of to-day. Living things are natural phenomena, and we feel that they must in some way be an outcome of the natural order. Science is more and more familiarizing our minds with the idea that the universe is a universe, a oneness; that its laws are continuous. We follow the chemistry of it to the farthest stars and there is no serious break or exception; it is all of one stuff. We follow the mechanics of it into the same abysmal depths, and there are no breaks or exceptions. The biology of it we cannot follow beyond our own little corner of the universe; indeed, we have no proof that there is any biology anywhere else. But if there is, it must be similar to our own. There is only one kind of electricity (though two phases of it), only one kind of light and heat, one kind of chemical affinity, in the universe; and hence only one kind of life. Looked at in its relation to the whole, life appears like a transient phenomenon of matter. I will not say accidental; it seems inseparably bound up with the cosmic processes, but, I may say, fugitive, superficial, circumscribed. Life comes and goes; it penetrates but a little way into the earth; it is confined to a certain range of temperature. Beyond a certain degree of cold, on the one hand, it does not appear; and beyond a certain degree of heat, on the other, it is cut off. Without water or moisture, it ceases; and without air, it is not. It has evidently disappeared from the moon, and probably from the inferior planets, and it is doubtful if it has yet appeared on any of the superior planets, save Mars.
Life comes to matter as the flowers come in the spring,—when the time is ripe for it,—and it disappears when the time is over-ripe. Man appears in due course and has his little day upon the earth, but that day must as surely come to an end. Yet can we conceive of the end of the physical order? the end of gravity? or of cohesion? The air may disappear, the water may disappear, combustion may cease; but oxygen, hydrogen, nitrogen, and carbon will continue somewhere.