III
Vitality is only a word, but it marks a cla.s.s of phenomena in nature that stands apart from all merely mechanical manifestations in the universe. The cosmos is a vast machine, but in this machine--this tremendous complex of physical forces--there appears, at least on this earth, in the course of its evolution, this something, or this peculiar manifestation of energy, that we call vital. Apparently it is a transient phase of activity in matter, which, unlike other chemical and physical activities, has its beginning and its ending, and out of which have arisen all the myriad forms of terrestrial life. The merely material forces, blind and haphazard from the first, did not arise in matter; they are inseparable from it; they are as eternal as matter itself; but the activities called vital arose in time and place, and must eventually disappear as they arose, while the career of the inorganic elements goes on as if life had never visited the sphere. Was it, or is it, a visitation--something _ab extra_ that implies super-mundane, or supernatural, powers?
Added to this wonder is the fact that the vital order has gone on unfolding through the geologic ages, mounting from form to form, or from order to order, becoming more and more complex, pa.s.sing from the emphasis of size of body, to the emphasis of size of brain, and finally from instinct and reflex activities to free volition, and the reason and consciousness of man; while the purely physical and chemical forces remain where they began. There has been endless change among them, endless shifting of the balance of power, but always the tendency to a dead equilibrium, while the genius of the organic forces has been in the power to disturb the equilibrium and to ride into port on the crest of the wave it has created, or to hang forever between the stable and the unstable.
So there we are, confronted by two apparently contrary truths. It is to me unthinkable that the vital order is not as truly rooted in the const.i.tution of things as are the mechanical and chemical orders; and yet, here we are face to face with its limited, fugitive, or transitional character. It comes and goes like the dews of the morning; it has all the features of an exceptional, unexpected, extraordinary occurrence--of miracle, if you will; but if the light which physical science turns on the universe is not a delusion, if the habit of mind which it begets is not a false one, then life belongs to the same category of things as do day and night, rain and sun, rest and motion.
Who shall reconcile these contradictions?
Huxley spoke for physical science when he said that he did not know what it was that const.i.tuted life--what it was that made the "wonderful difference between the dead particles and the living particles of matter appearing in other respects identical." He thought there might be some bond between physico-chemical phenomena, on the one hand, and vital phenomena, on the other, which philosophers will some day find out.
Living matter is characterized by "spontaneity of action," which is entirely absent from inert matter. Huxley cannot or does not think of a vital force distinct from all other forces, as the cause of life phenomena, as so many philosophers have done, from Aristotle down to our day. He finds protoplasm to be the physical basis of life; it is one in both the vegetable and animal worlds; the animal takes it from the vegetable, and the vegetable, by the aid of sunlight, takes or manufactures it from the inorganic elements. But protoplasm is living matter. Before there was any protoplasm, what brought about the stupendous change of the dead into the living? Protoplasm makes more protoplasm, as fire makes more fire, but what kindled the first spark of this living flame? Here we corner the mystery, but it is still a mystery that defies us. Cause and effect meet and are lost in each other. Science cannot admit a miracle, or a break in the continuity of life, yet here it reaches a point where no step can be taken. Huxley"s ill.u.s.trations do not help his argument. "Protoplasm," he says, "is the clay of the potter; which, bake it and paint it as he will, remains clay, separated by artifice, and not by nature, from the commonest brick or sun-dried clod." Clay is certainly the physical basis of the potter"s art, but would there be any pottery in the world if it contained only clay? Do we not have to think of the potter? In the same way, do we not have to think of something that fashions these myriad forms of life out of protoplasm?--and back of that, of something that begat protoplasm out of non-protoplasmic matter, and started the flame of life going? Life accounts for protoplasm, but what accounts for life? We have to think of the living clay as separated by Nature from the inert "sun-dried clod."
There is something in the one that is not in the other. There is really no authentic a.n.a.logy between the potter"s art and Nature"s art of life.
The force of the a.n.a.logy, if it has any, drives us to the conclusion that life is an ent.i.ty, or an agent, working upon matter and independent of it.
There is more wit than science in Huxley"s question, "What better philosophical status has vitality than aquosity?" There is at least this difference: When vitality is gone, you cannot recall it, or reproduce it by your chemistry; but you can recombine the two gases in which you have decomposed water, any number of times, and get your aquosity back again; it never fails; it is a power of chemistry. But vitality will not come at your beck; it is not a chemical product, at least in the same sense that water is; it is not in the same category as the wetness or liquidity of water. It is a name for a phenomenon--the most remarkable phenomenon in nature. It is one that the art of man is powerless to reproduce, while water may be made to go through its cycle of change--solid, fluid, vapor, gas--and always come back to water. Well does the late Professor Brooks, of Johns Hopkins, say that "living things do, in some way and in some degree, control or condition inorganic nature; that they hold their own by setting the mechanical properties of matter in opposition to each other, and that this is their most notable and distinctive characteristic." Does not Ray Lankester, the irate champion of the mechanistic view of life, say essentially the same thing when he calls man the great Insurgent in Nature"s camp--"crossing her courses, reversing her processes, and defeating her ends?"
Life appears like the introduction of a new element or force or tendency into the cosmos. Henceforth the elements go new ways, form new compounds, build up new forms, and change the face of nature. Rivers flow where they never would have flowed without it, mountains fall in a s.p.a.ce of time during which they never would have fallen; barriers arise, rough ways are made smooth, a new world appears--the world of man"s physical and mental activities.
If the G.o.ds of the inorganic elements are neither for nor against us, but utterly indifferent to us, how came we here? Nature"s method is always from the inside, while ours is from the outside; hers is circular while ours is direct. We think, as Bergson says, of things created, and of a thing that creates, but things in nature are not created, they are evolved; they grow, and the thing that grows is not separable from the force that causes it to grow. The water turns the wheel, and can be shut off or let on. This is the way of the mechanical world. But the wheels in organic nature go around from something inside them, a kind of perpetual motion, or self-supplying power. They are not turned, they turn; they are not repaired, they repair. The nature of living things cannot be interpreted by the laws of mechanical and chemical things, though mechanics and chemistry play the visible, tangible part in them.
If we must discard the notion of a vital force, we may, as Professor Hartog suggests, make use of the term "vital behavior."
Of course man tries everything by himself and his own standards. He knows no intelligence but his own, no prudence, no love, no mercy, no justice, no economy, but his own, no G.o.d but such a one as fits his conception.
In view of all these things, how man got here is a problem. Why the slender thread of his line of descent was not broken in the warrings and upheavals of the terrible geologic ages, what power or agent took a hand in furthering his development, is beyond the reach of our biologic science.
Man"s is the only intelligence, as we understand the word, in the universe, and his intelligence demands something akin to intelligence in the nature from which he sprang.
VII
LIFE AND MIND
I
There are three kinds of change in the world in which we live--physical and mechanical change which goes on in time and place among the tangible bodies about us, chemical change which goes on in the world of hidden molecules and atoms of which bodies are composed, and vital change which involves the two former, but which also involves the mysterious principle or activity which we call life. Life comes and goes, but the physical and chemical orders remain. The vegetable and animal kingdoms wax and wane, or disappear entirely, but the physico-chemical forces are as indestructible as matter itself. This fugitive and evanescent character of life, the way it uses and triumphs over the material forces, setting up new chemical activities in matter, sweeping over the land-areas of the earth like a conflagration, lifting the inorganic elements up into myriads of changing and beautiful forms, inst.i.tuting a vast number of new chemical processes and compounds, defying the laboratory to reproduce it or kindle its least spark--a flame that cannot exist without carbon and oxygen, but of which carbon and oxygen do not hold the secret, a fire reversed, building up instead of pulling down, in the vegetable with power to absorb and trans.m.u.te the inorganic elements into leaves and fruit and tissue; in the animal with power to change the vegetable products into bone and muscle and nerve and brain, and finally into thought and consciousness; run by the solar energy and dependent upon it, yet involving something which the sunlight cannot give us; in short, an activity in matter, or in a limited part of matter, as real as the physico-chemical activity, but, unlike it, defying all a.n.a.lysis and explanation and all our attempts at synthesis.
It is this character of life, I say, that so easily leads us to look upon it as something _ab extra_, or super-added to matter, and not an evolution from it. It has led Sir Oliver Lodge to conceive of life as a distinct ent.i.ty, existing independent of matter, and it is this conception that gives the key to Henri Bergson"s wonderful book, "Creative Evolution."
There is possibly or probably a fourth change in matter, physical in its nature, but much more subtle and mysterious than any of the physical changes which our senses reveal to us. I refer to radioactive change, or to the atomic transformation of one element into another, such as the change of radium into helium, and the change of helium into lead--a subject that takes us to the borderland between physics and chemistry where is still debatable ground.
I began by saying that there were three kinds of changes in matter--the physical, the chemical, and the vital. But if we follow up this idea and declare that there are three kinds of force also, claiming this distinction for the third term of our proposition, we shall be running counter to the main current of recent biological science. "The idea that a peculiar "vital force" acts in the chemistry of life," says Professor Soddy, "is extinct."
"Only chemical and physical agents influence the vital processes," says Professor Czapek, of the University of Prague, "and we need no longer take refuge in mysterious "vital forces" when we want to explain these."
Tyndall was obliged to think of a force that guided the molecules of matter into the special forms of a tree. This force was in the ultimate particles of matter. But when he came to the brain and to consciousness, he said a new product appeared that defies mechanical treatment.
The attempt of the biological science of our time to wipe out all distinctions between the living and the non-living, solely because scientific a.n.a.lysis reveals no difference, is a curious and interesting phenomenon.
Professor Schafer, in his presidential address before the British a.s.sociation in 1912, argued that all the main characteristics of living matter, such as a.s.similation and disa.s.similation, growth and reproduction, spontaneous and amoeboid movement, osmotic pressure, karyokinesis, etc., were equally apparent in the non-living; therefore he concluded that life is only one of the many chemical reactions, and that it is not improbable that it will yet be produced by chemical synthesis in the laboratory. The logic of the position taken by Professor Schafer and of the school to which he belongs, demands this artificial production of life--an achievement that seems no nearer than it did a half-century ago. When it has been attained, the problem will be simplified, but the mystery of life will by no means have been cleared up. One follows these later biochemists in working out their problem of the genesis of life with keen interest, but always with a feeling that there is more in their conclusions than is justified by their premises. For my own part, I am convinced that whatever is, is natural, but to obtain life I feel the need of something of a different order from the force that evokes the spark from the flint and the steel, or brings about the reaction of chemical compounds. If asked to explain what this something is that is characteristic of living matter, I should say intelligence.
The new school of biologists start with matter that possesses extraordinary properties--with matter that seems inspired with the desire for life, and behaving in a way that it never will behave in the laboratory. They begin with the earth"s surface warm and moist, the atmosphere saturated with watery vapor and carbon dioxide and many other complex unstable compounds; then they summon all the material elements of life--carbon, oxygen, hydrogen, and nitrogen, with a little sodium, chlorine, iron, sulphur, phosphorus, and others--and make these run together to form a jelly-like body called a colloid; then they endow this jelly ma.s.s with the power of growth, and of subdivision when it gets too large; they make it able to absorb various unstable compounds from the air, giving it internal stores of energy, "the setting free of which would cause automatic movements in the lump of jelly." Thus they lay the foundations of life. This carbonaceous material with properties of movement and subdivision due to mechanical and physical forces is the immediate ancestor of the first imaginary living being, the _protobion_.
To get this _protobion_ the chemists summon a reagent known as a catalyser. The catalyser works its magic on the jelly ma.s.s. It sets up a wonderful reaction by its mere presence, without parting with any of its substance. Thus, if a bit of platinum which has this catalytic power is dropped into a vessel containing a mixture of oxygen and hydrogen, the two gases instantly unite and form water. A catalyser introduced in the primordial jelly liberates energy and gives the substance power to break up the various complex unstable compounds into food, and promote growth and subdivision. In fact, it awakens or imparts a vital force and leads to "indefinite increase, subdivision, and movement."
With Professor Schafer there is first "the fortuitous production of life upon this globe"--the chance meeting or jostling of the elements that resulted in a bit of living protoplasm, "or a ma.s.s of colloid slime" in the old seas, or on their sh.o.r.es, "possessing the property of a.s.similation and therefore of growth." Here the whole mystery is swallowed at one gulp. "Reproduction would follow as a matter of course," because all material of this physical nature--fluid or semi-fluid in character--"has a tendency to undergo subdivision when its bulk exceeds a certain size."
"A ma.s.s of colloidal slime" that has the power of a.s.similation and of growth and reproduction, is certainly a new thing in the world, and no chemical a.n.a.lysis of it can clear up the mystery. It is easy enough to produce colloidal slime, but to endow it with these wonderful powers so that "the promise and the potency of all terrestrial life" slumbers in it is a staggering proposition.
Whatever the character of this subdivision, whether into equal parts or in the form of buds, "every separate part would resemble the parent in chemical and physical properties, and would equally possess the property of taking in and a.s.similating suitable material from its liquid environment, growing in bulk and reproducing its like by subdivision.
In this way from any beginning of living material a primitive form of life would spread and would gradually people the globe. The establishment of life being once effected, all forms of organization follow under the inevitable laws of evolution." Why all forms of organization--why the body and brain of man--must inevitably follow from the primitive bit of living matter, is just the question upon which we want light. The proposition begs the question. Certainly when you have got the evolutionary process once started in matter which has these wonderful powers, all is easy. The professor simply describes what has taken place and seems to think that the mystery is thereby cleared up, as if by naming all the parts of a machine and their relation to one another, the machine is accounted for. What caused the iron and steel and wood of the machine to take this special form, while in other cases the iron and steel and wood took other radically different forms, and vast quant.i.ties of these substances took no form at all?
In working out the evolution of living forms by the aid of the blind physical and chemical agents alone, Professor Schafer unconsciously ascribes the power of choice and purpose to the individual cells, as when he says that the cells of the external layer sink below the surface for better protection and better nutrition. It seems to have been a matter of choice or will that the cells developed a nervous system in the animal and not in the vegetable. Man came because a few cells in some early form of life acquired a slightly greater tendency to react to an external stimulus. In this way they were brought into closer touch with the outer world and thereby gained the lead of their duller neighbor cells, and became the real rulers of the body, and developed the mind.
It is bewildering to be told by so competent a person as Professor Schafer that at bottom there is no fundamental difference between the living and non-living. We need not urge the existence of a peculiar vital force, as distinct from all other forces, but all distinctions between things are useless if we cannot say that a new behavior is set up in matter which we describe by the word "vital," and that a new principle is operative in organized matter which we must call "intelligence." Of course all movements and processes of living beings are in conformity with the general laws of matter, but does such a statement necessarily rule out all idea of the operation of an organizing and directing principle that is not operative in the world of inanimate things?
In Schafer"s philosophy evolution is purely a mechanical process--there is no inborn tendency, no inherent push, no organizing effort, but all results from the blind groping and chance jostling of the inorganic elements; from the molecules of undifferentiated protoplasm to the brain of a Christ or a Plato, is just one series of unintelligent physical and chemical activities in matter.
May we not say that all the marks or characteristics of a living body which distinguish it in our experience from an inanimate body, are of a non-scientific character, or outside the sphere of experimental science?
We recognize them as readily as we distinguish day from night, but we cannot describe them in the fixed terms of science. When we say growth, metabolism, osmosis, the colloidal state, science points out that all this may be affirmed of inorganic bodies. When we say a life principle, a vital force or soul or spirit or intelligence, science turns a deaf ear.
The difference between the living and the non-living is not so much a physical difference as a metaphysical difference. Living matter is actuated by intelligence. Its activities are spontaneous and self-directing. The rock, and the tree that grows beside it, and the insects and rodents that burrow under it, may all be made of one stuff, but their difference to the beholder is fundamental; there is an intelligent activity in the one that is not in the other. Now no scientific a.n.a.lysis of a body will reveal the secret of this activity.
As well might your a.n.a.lysis of a phonographic record hope to disclose a sonata of Beethoven latent in the waving lines. No power of chemistry could reveal any difference between the gray matter of Plato"s brain and that of the humblest citizen of Athens. All the difference between man, all that makes a man a man, and an ox an ox, is beyond the reach of any of your physico-chemical tests. By the same token the gulf that separates the organic from the inorganic is not within the power of science to disclose. The biochemist is bound to put life in the category of the material forces because his science can deal with no other. To him the word "vital" is a word merely, it stands for no reality, and the secret of life is merely a chemical reaction. A living body awakens a train of ideas in our minds that a non-living fails to awaken--a train of ideas that belong to another order from that awakened by scientific demonstration. We cannot blame science for ruling out that which it cannot touch with its a.n.a.lysis, or repeat with its synthesis. The phenomena of life are as obvious to us as anything in the world; we know their signs and ways, and witness their power, yet in the alembic of our science they turn out to be only physico-chemical processes; hence that is all there is of them. Vitality, says Huxley, has no more reality than the horology of a clock. Yet Huxley sees three equal realities in the universe--matter, energy, and consciousness. But consciousness is the crown of a vital process. Hence it would seem as if there must be something more real in vitality than Huxley is willing to admit.
II
Nearly all the later biologists or biological philosophers are as shy of the term "vital force," and even of the word "vitality," as they are of the words "soul," "spirit," "intelligence," when discussing natural phenomena. To experimental science such words have no meaning because the supposed realities for which they stand are quite beyond the reach of scientific a.n.a.lysis. Ray Lankester, in his "Science from an Easy Chair," following Huxley, compares vitality with aquosity, and says that to have recourse to a vital principle or force to explain a living body is no better philosophy than to appeal to a principle of aquosity to explain water. Of course words are words, and they have such weight with us that when we have got a name for a thing it is very easy to persuade ourselves that the thing exists. The terms "vitality," "vital force,"
have long been in use, and it is not easy to convince one"s self that they stand for no reality. Certain it is that living and non-living matter are sharply separated, though when reduced to their chemical const.i.tuents in the laboratory they are found to be identical. The carbon, the hydrogen, the nitrogen, the oxygen, and the lime, sulphur, iron, etc., in a living body are in no way peculiar, but are the same as these elements in the rocks and the soil. We are all made of one stuff; a man and his dog are made of one stuff; an oak and a pine are made of one stuff; Jew and Gentile are made of one stuff. Should we be justified, then, in saying that there is no difference between them?
There is certainly a moral and an intellectual difference between a man and his dog, if there is no chemical and mechanical difference. And there is as certainly as wide or a wider difference between living and non-living matter, though it be beyond the reach of science to detect.
For this difference we have to have a name, and we use the words "vital," "vitality," which seem to me to stand for as undeniable realities as the words heat, light, chemical affinity, gravitation.
There is not a principle of roundness, though "nature centres into b.a.l.l.s," nor of squareness, though crystallization is in right lines, nor of aquosity, though two thirds of the surface of the earth is covered with water. Can we on any better philosophical grounds say that there is a principle of vitality, though the earth swarms with living beings? Yet the word vitality stands for a reality, it stands for a peculiar activity in matter--for certain movements and characteristics for which we have no other term. I fail to see any a.n.a.logy between aquosity and that condition of matter we call vital or living. Aquosity is not an activity, it is a property, the property of wetness; viscosity is a term to describe other conditions of matter; solidity, to describe still another condition; and opacity and transparency, to describe still others--as they affect another of our senses. But the vital activity in matter is a concrete reality. With it there goes the organizing tendency or impulse, and upon it hinges the whole evolutionary movement of the biological history of the globe. We can do all sorts of things with water and still keep its aquosity. If we resolve it into its const.i.tuent gases we destroy its aquosity, but by uniting these gases chemically we have the wetness back again. But if a body loses its vitality, its life, can we by the power of chemistry, or any other power within our reach, bring the vitality back to it? Can we make the dead live? You may bray your living body in a mortar, destroy every one of its myriad cells, and yet you may not extinguish the last spark of life; the protoplasm is still living. But boil it or bake it and the vitality is gone, and all the art and science of mankind cannot bring it back again. The physical and chemical activities remain after the vital activities have ceased.
Do we not then have to supply a non-chemical, a non-physical force or factor to account for the living body? Is there no difference between the growth of a plant or an animal, and the increase in size of a sand-bank or a snow-bank, or a river delta? or between the wear and repair of a working-man"s body and the wear and repair of the machine he drives? Excretion and secretion are not in the same categories. The living and the non-living mark off the two grand divisions of matter in the world in which we live, as no two terms merely descriptive of chemical and physical phenomena ever can. Life is a motion in matter, but of another order from that of the physico-chemical, though inseparable from it. We may forego the convenient term "vital force."
Modern science shies at the term "force." We must have force or energy or pressure of some kind to lift dead matter up into the myriad forms of life, though in the last a.n.a.lysis of it it may all date from the sun.
When it builds a living body, we call it a vital force; when it builds a gravel-bank, or moves a glacier, we call it a mechanical force; when it writes a poem or composes a symphony, we call it a psychic force--all distinctions which we cannot well dispense with, though of the ultimate reality for which these terms stand we can know little. In the latest science heat and light are not substances, though electricity is. They are peculiar motions in matter which give rise to sensations in certain living bodies that we name light and heat, as another peculiar motion in matter gives rise to a sensation we call sound. Life is another kind of motion in certain aggregates of matter--more mysterious or inexplicable than all others because it cannot be described in terms of the others, and because it defies the art and science of man to reproduce.
Though the concepts "vital force" and "life principle" have no standing in the court of modern biological science, it is interesting to observe how often recourse is had by biological writers to terms that embody the same idea. Thus the German physiologist Verworn, the determined enemy of the old conception of life, in his great work on "Irritability," has recourse to "the specific energy of living substances." One is forced to believe that without this "specific energy" his "living substances" would never have arisen out of the non-living.
Professor Moore, of Liverpool University, as I have already pointed out while discussing the term "vital force," invents a new phrase, "biotic energy," to explain the same phenomena. Surely a force by any other name is no more and no less potent. Both Verworn and Moore feel the need, as we all do, of some term, or terms, by which to explain that activity in matter which we call vital. Other writers have referred to "a peculiar power of synthesis" in plants and animals, which the inanimate forms do not possess.
Ray Lankester, to whom I have already referred in discussing this subject, helps himself out by inventing, not a new force, but a new substance in which he fancies "resides the peculiar property of living matter." He calls this hypothetical substance "plasmogen," and thinks of it as an ultimate chemical compound hidden in protoplasm. Has this "ultimate molecule of life" any more scientific or philosophical validity than the old conception of a vital force? It looks very much like another name for the same thing--an attempt to give the mind something to take hold of in dealing with the mystery of living things.
This imaginary "life-stuff" of the British scientist is entirely beyond the reach of chemical a.n.a.lysis; no man has ever seen it or proved its existence. In fact it is simply an invention of Ray Lankester to fill a break in the sequence of observed phenomena. Something seems to possess the power of starting or kindling that organizing activity in a living body, and it seems to me it matters little whether we call it "plasmogen," or a "life principle," or "biotic energy," or what not; it surely leavens the loaf. Matter takes on new activities under its influence. Ray Lankester thinks that plasmogen came into being in early geologic ages, and that the conditions which led to its formation have probably never recurred. Whether he thinks its formation was merely a chance hit or not, he does not say.
We see matter all about us, acted upon by the mechanico-chemical forces, that never takes on any of the distinctive phenomena of living bodies.
Yet Verworn is convinced that if we could bring the elements of a living body together as Nature does, in the same order and proportion, and combine them in the selfsame way, or bring about the vital conditions, a living being would result. Undoubtedly. It amounts to saying that if we had Nature"s power we could do what she does. _If_ we could marry the elements as she does, and bless the banns as she seems to, we could build a man out of a clay-bank. But clearly physics and chemistry alone, as we know and practice them, are not equal to the task.
III