I
There is one phase of the much-discussed question of the nature and
origin of life which, so far as I know, has not been considered either
by those who hold a brief for the physico-chemical view or by those who
stand for some form of vitalism or idealism. I refer to the small part
that life plays in the total scheme of things. The great cosmic machine
would go on just as well without it. Its relation to the whole appears
to be little different from that of a man to the train in which he
journeys. Life rides on the mechanical and chemical forces, but it does
not seem to be a part of them, nor identical with them, because they
were before it, and will continue after it is gone.
The everlasting, all-inclusive thing in this universe seems to be inert
matter with the energy it holds; while the slight, flitting, casual
thing seems to be living matter. The inorganic is from all eternity to
all eternity; it is distributed throughout all space and endures through
all time, while the organic is, in comparison, only of the here and the
now; it was not here yesterday, and it may not be here to-morrow; it
comes and goes. Life is like a bird of passage which alights and tarries
for a time and is gone, and the places where it perched and nested and
led forth its brood know it no more. Apparently it flits from world to
world as the great cosmic spring comes to each, and departs as the
cosmic winter returns to each. It is a visitor, a migrant, a frail,
timid thing, which waits upon the seasons and flees from the coming
tempests and vicissitudes.
How casual, uncertain, and inconsequential the vital order seems in our
own solar system--a mere incident or by-product in its cosmic evolution!
Astronomy sounds the depths of space, and sees only mechanical and
chemical forces at work there. It is almost certain that only a small
fraction of the planetary surfaces is the abode of life. On the earth
alone, of all the great family of planets and satellites, is the vital
order in full career. It may yet linger upon Mars, but it is evidently
waning. On the inferior planets it probably had its day long ago, while
it must be millions of years before it comes to the superior planets, if
it ever comes to them. What a vast, inconceivable outlay of time and
energy for such small returns! Evidently the vital order is only an
episode, a transient or secondary phase of matter in the process of
sidereal evolution. Astronomic space is strewn with dead worlds, as a
New England field is with drift boulders. That life has touched and
tarried here and there upon them can hardly be doubted, but if it is
anything more than a passing incident, an infant crying in the night, a
flush of color upon the cheek, a flower blooming by the wayside,
appearances are against it.
We read our astronomy and geology in the light of our enormous egotism,
and appropriate all to ourselves; but science sees in our appearance
here a no more significant event than in the foam and bubbles that whirl
and dance for a moment upon the river's current. The bubbles have their
reason for being; all the mysteries of molecular attraction and
repulsion may be involved in their production; without the solar energy,
and the revolution of the earth upon its axis, they would not appear;
and yet they are only bubbles upon the river's current, as we are
bubbles upon the stream of energy that flows through the universe.
Apparently the cosmic game is played for us no more than for the
parasites that infest our bodies, or for the frost ferns that form upon
our window-panes in winter. The making of suns and systems goes on in
the depths of space, and doubtless will go on to all eternity, without
any more reference to the vital order than to the chemical compounds.
The amount of living matter in the universe, so far as we can penetrate
it, compared with the non-living, is, in amount, like a flurry of snow
that whitens the fields and hills of a spring morning compared to the
miles of rock and soil beneath it; and with reference to geologic time
it is about as fleeting. In the vast welter of suns and systems in the
heavens above us, we see only dead matter, and most of it is in a
condition of glowing metallic vapor. There are doubtless living
organisms upon some of the invisible planetary bodies, but they are
probably as fugitive and temporary as upon our own world. Much of the
surface of the earth is clothed in a light vestment of life, which, back
in geologic time, seems to have more completely enveloped it than at
present, as both the arctic and the antarctic regions bear evidence in
their coal-beds and other fossil remains of luxuriant vegetable growths.
Strip the earth of its thin pellicle of soil, thinner with reference to
the mass than is the peel to the apple, and you have stripped it of its
life. Or, rob it of its watery vapor and the carbon dioxide in the air,
both stages in its evolution, and you have a dead world. The huge globe
swings through space only as a mass of insensate rock. So limited and
evanescent is the world of living matter, so vast and enduring is the
world of the non-living. Looked at in this way, in the light of physical
science, life, I repeat, seems like a mere passing phase of the cosmic
evolution, a flitting and temporary stage of matter which it passes
through in the procession of changes on the surface of a cooling planet.
Between the fiery mist of the nebula, and the frigid and consolidated
globe, there is a brief span, ranging over about one hundred and twenty
degrees of temperature, where life appears and organic evolution takes
place. Compared with the whole scale of temperature, from absolute zero
to the white heat of the hottest stars, it is about a hand's-breadth
compared to a mile.
Life processes cease, but chemical and mechanical processes go on
forever. Life is as fugitive and uncertain as the bow in the clouds,
and, like the bow in the clouds, is confined to a limited range of
conditions. Like the bow, also, it is a perpetual creation, a constant
becoming, and its source is not in the matter through which it is
manifested, though inseparable from it. The material substance of life,
like the rain-drops, is in perpetual flux and change; it hangs always on
the verge of dissolution and vanishes when the material conditions fail,
to be renewed again when they return. We know, do we not? that life is
as literally dependent upon the sun as is the rainbow, and equally
dependent upon the material elements; but whether the physical
conditions sum up the whole truth about it, as they do with the bow, is
the insoluble question. Science says "Yes," but our philosophy and our
religion say "No." The poets and the prophets say "No," and our hopes
and aspirations say "No."