I
Still the problem of living things haunts my mind and, let me warn my
reader, will continue to haunt it throughout the greater part of this
volume. The final truth about it refuses to be spoken. Every effort to
do so but gives one new evidence of how insoluble the problem is.
In this world of change is there any other change to be compared with
that in matter, from the dead to the living?--a change so great that
most minds feel compelled to go outside of matter and invoke some
super-material force or agent to account for it. The least of living
things is so wonderful, the phenomena it exhibits are so fundamentally
unlike those of inert matter, that we invent a word for it, _vitality_;
and having got the word, we conceive of a vital force or principle to
explain vital phenomena. Hence vitalism--a philosophy of living things,
more or less current in the world from Aristotle's time down to our own.
It conceives of something in nature super-mechanical and super-chemical,
though inseparably bound up with these things. There is no life without
material and chemical forces, but material and chemical forces do not
hold the secret of life. This is vitalism as opposed to mechanism, or
scientific materialism, which is the doctrine of the all-sufficiency of
the physical forces operating in the inorganic world to give rise to all
the phenomena of the organic world--a doctrine coming more and more in
vogue with the progress of physical science. Without holding to any
belief in the supernatural or the teleological, and while adhering to
the idea that there has been, and can be, no break in the causal
sequence in this world, may one still hold to some form of vitalism, and
see in life something more than applied physics and chemistry?
Is biology to be interpreted in the same physical and chemical terms as
geology? Are biophysics and geophysics one and the same? One may freely
admit that there cannot be two kinds of physics, nor two kinds of
chemistry--not one kind for a rock, and another kind for a tree, or a
man. There are not two species of oxygen, nor two of carbon, nor two of
hydrogen and nitrogen--one for living and one for dead matter. The water
in the human body is precisely the same as the water that flows by in
the creek or that comes down when it rains; and the sulphur and the lime
and the iron and the phosphorus and the magnesium are identical, so far
as chemical analysis can reveal, in the organic and the inorganic
worlds. But are we not compelled to think of a kind of difference
between a living and a non-living body that we cannot fit into any of
the mechanical or chemical concepts that we apply to the latter?
Professor Loeb, with his "Mechanistic Conception of Life"; Professor
Henderson, of Harvard, with his "Fitness of the Environment"; Professor
Le Dantec, of the Sorbonne in Paris, with his volume on "The Nature and
Origin of Life," published a few years since; Professor Schäfer,
President of the British Association, Professor Verworn of Bonn, and
many others find in the laws and properties of matter itself a
sufficient explanation of all the phenomena of life. They look upon the
living body as only the sum of its physical and chemical activities;
they do not seem to feel the need of accounting for life itself--for
that something which confers vitality upon the heretofore non-vital
elements. That there is new behavior, that there are new chemical
compounds called organic,--tens of thousands of them not found in
inorganic nature,--that there are new processes set up in aggregates of
matter,--growth, assimilation, metabolism, reproduction, thought,
emotion, science, civilization,--no one denies.
How are we going to get these things out of the old physics and
chemistry without some new factor or agent or force? To help ourselves
out here with a "vital principle," or with spirit, or a creative
impulse, as Bergson does, seems to be the only course open to certain
types of mind. Positive science cannot follow us in this step, because
science is limited to the verifiable. The stream of forces with which it
deals is continuous; it must find the physical equivalents of all the
forces that go into the body in the output of the body, and it cannot
admit of a life force which it cannot trace to the physical forces.
What has science done to clear up this mystery of vitality? Professor
Loeb, our most eminent experimental biologist, has succeeded in
fertilizing the eggs of some low forms of sea life by artificial means;
and in one instance, at least, it is reported that the fatherless form
grew to maturity. This is certainly an interesting fact, but takes us no
nearer the solution of the mystery of vitality than the fact that
certain chemical compounds may stimulate the organs of reproduction
helps to clear up the mystery of generation; or the fact that certain
other chemical compounds help the digestive and assimilative processes
and further the metabolism of the body assists in clearing up the
mystery that attaches to these things. In all such cases we have the
living body to begin with. The egg of the sea-urchin and the egg of the
jelly-fish are living beings that responded to certain chemical
substances, so that a process is set going in their cell life that is
equivalent to fertilization. It seems to me that the result of all
Professor Loeb's valuable inquiries is only to give us a more intimate
sense of how closely mechanical and chemical principles are associated
and identified with all the phenomena of life and with all animal
behavior. Given a living organism, mechanics and chemistry will then
explain much of its behavior--practically all the behavior of the lower
organisms, and much of that of the higher. Even when we reach man, our
reactions to the environment and to circumstances play a great part in
our lives; but dare we say that will, liberty of choice, ideation, do
not play a part also? How much reality there is in the so-called animal
will, is a problem; but that there is a foundation for our belief in the
reality of the human will, I, for one, do not for a moment doubt. The
discontinuity here is only apparent and not real. We meet with the same
break when we try to get our mental states, our power of thought--a
poem, a drama, a work of art, a great oration--out of the food we eat;
but life does it, though our science is none the wiser for it. Our
physical life forms a closed circle, science says, and what goes into
our bodies as physical force, must come out in physical force, or as
some of its equivalents. Well, one of the equivalents, transformed by
some unknown chemism within us, is our psychic force, or states of
consciousness. The two circles, the physical and the psychical, are not
concentric, as Fiske fancied, but are linked in some mysterious way.
Professor Loeb is a master critic of the life processes; he and his
compeers analyze them as they have never been analyzed before; but the
solution of the great problem of life that we are awaiting does not
come. A critic may resolve all of Shakespeare's plays into their
historic and other elements, but that will not account for Shakespeare.
Nature's synthesis furnishes occasions for our analysis. Most assuredly
all psychic phenomena have a physical basis; we know the soul only
through the body; but that they are all of physico-chemical origin, is
another matter.