IV

THE BAFFLING PROBLEM

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