When for the third or fourth time during the spring or summer I take my hoe and go out and cut off the heads of the lusty burdocks that send out their broad leaves along the edge of my garden or lawn, I often ask myself, "What is this thing that is so hard to scotch here in the grass?" I decapitate it time after time and yet it forthwith gets itself another head. We call it burdock, but what is burdock, and why does it not change into yellow dock, or into a cabbage? What is it that is so constant and so irrepressible, and before the summer is ended will be lying in wait here with its ten thousand little hooks to attach itself to every skirt or bushy tail or furry or woolly coat that comes along, in order to get free transportation to other lawns and gardens, to green fields and pastures new?

It is some living thing; but what is a living thing, and how does it differ from a mechanical and non-living thing? If I smash or overturn the sundial with my hoe, or break the hoe itself, these things stay smashed and broken, but the burdock mends itself, renews itself, and, if I am not on my guard, will surreptitiously mature some of the burs before the season is passed.

Evidently a living thing is radically different from a mechanical thing; yet modern physical science tells me that the burdock is only another kind of machine, and manifests nothing but the activity of the mechanical and chemical principles that we see in operation all about us in dead matter; and that a little different mechanical arrangement of its ultimate atoms would turn it into a yellow dock or into a cabbage, into an oak or into a pine, into an ox or into a man.

I see that it is a machine in this respect, that it is set going by a force exterior to itself—the warmth of the sun acting upon it, and upon the moisture in the soil; but it is unmechanical in that it repairs itself and grows and reproduces itself, and after it has ceased running can never be made to run again. After I have reduced all its activities to mechanical and chemical principles, my mind seems to see something that chemistry and mechanics do not explain—something that avails itself of these forces, but is not of them. This may be only my anthropomorphic way of looking at things, but are not all our ways of looking at things anthropomorphic? How can they be any other? They cannot be deific since we are not gods. They may be scientific. But what is science but a kind of anthropomorphism? Kant wisely said, "It sounds at first singular, but is none the less certain, that the understanding does not derive its laws from nature, but prescribes them to nature." This is the anthropomorphism of science.

If I attribute the phenomenon of life to a vital force or principle, am I any more unscientific than I am when I give a local habitation and a name to any other causal force, as gravity, chemical affinity, cohesion, osmosis, electricity, and so forth? These terms stand for certain special activities in nature and are as much the inventions of our own minds as are any of the rest of our ideas.

We can help ourselves out, as Haeckel does, by calling the physical forces—such as the magnet that attracts the iron filings, the powder that explodes, the steam that drives the locomotive, and the like—"living inorganics," and looking upon them as acting by "living force as much as the sensitive mimosa does when it contracts its leaves at touch." But living force is what we are trying to differentiate from mechanical force, and what do we gain by confounding the two? We can only look upon a living body as a machine by forming new conceptions of a machine—a machine utterly unmechanical, which is a contradiction of terms.

A man may expend the same kind of force in thinking that he expends in chopping his wood, but that fact does not put the two kinds of activity on the same level. There is no question but that the food consumed is the source of the energy in both cases, but in the one the energy is muscular, and in the other it is nervous. When we speak of mental or spiritual force, we have as distinct a conception as when we speak of physical force. It requires physical force to produce the effect that we call mental force, though how the one can result in the other is past understanding. The law of the correlation and conservation of energy requires that what goes into the body as physical force must come out in some form of physical force—heat, light, electricity, and so forth.

Science cannot trace force into the mental realm and connect it with our states of consciousness. It loses track of it so completely that men like Tyndall and Huxley and Spencer pause before it as an inscrutable mystery, while John Fiske helps himself out with the conception of the soul as quite independent of the body, standing related to it as the musician is related to his instrument. This idea is the key to Fiske's proof of the immortality of the soul. Finding himself face to face with an insoluble mystery, he cuts the knot, or rather, clears the chasm, by this extra-scientific leap. Since the soul, as we know it, is inseparably bound up with physical conditions, it seems to me that a more rational explanation of the phenomenon of mentality is the conception that the physical force and substance that we use up in a mental effort or emotional experience gives rise, through some unknown kind of molecular activity, to something which is analogous to the electric current in a live wire, and which traverses the nerves and results in our changing states of consciousness. This is the mechanistic explanation of mind, consciousness, etc., but it is the only one, or kind of one, that lends itself to scientific interpretation. Life, spirit, consciousness, may be a mode of motion as distinct from all other modes of motion, such as heat, light, electricity, as these are distinct from each other.

When we speak of force of mind, force of character, we of course speak in parables, since the force here alluded to is an experience of our own minds entirely and would not suffice to move the finest dust-particle in the air.

There could be no vegetable or animal life without the sunbeam, yet when we have explained or accounted for the growth of a tree in terms of the chemistry and physics of the sunbeam, do we not have to figure to ourselves something in the tree that avails itself of this chemistry, that uses it and profits by it? After this mysterious something has ceased to operate, or play its part, the chemistry of the sunbeam is no longer effective, and the tree is dead.

Without the vibrations that we call light, there would have been no eye. But, as Bergson happily says, it is not light passively received that makes the eye; it is light meeting an indwelling need in the organism, which amounts to an active creative principle, that begets the eye. With fish in underground waters this need does not arise; hence they have no sight. Fins and wings and legs are developed to meet some end of the organism, but if the organism were not charged with an expansive or developing force or impulse, would those needs arise?

Why should the vertebrate series have risen through the fish, the reptile, the mammal, to man, unless the manward impulse was inherent in the first vertebrate; something that struggled, that pushed on and up from the more simple to the more complex forms? Why did not unicellular life always remain unicellular? Could not the environment have acted upon it endlessly without causing it to change toward higher and more complex forms, had there not been some indwelling aboriginal tendency toward these forms? How could natural selection, or any other process of selection, work upon species to modify them, if there were not something in species pushing out and on, seeking new ways, new forms, in fact some active principle that is modifiable?

Life has risen by stepping-stones of its dead self to higher things. Why has it risen? Why did it not keep on the same level, and go through the cycle of change, as the inorganic does, without attaining to higher forms? Because, it may be replied, it was life, and not mere matter and motion—something that lifts matter and motion to a new plane.

Under the influence of the life impulse, the old routine of matter—from compound to compound, from solid to fluid, from fluid to gaseous, from rock to soil, the cycle always ending where it began—is broken into, and cycles of a new order are instituted. From the stable equilibrium which dead matter is always seeking, the same matter in the vital circuit is always seeking the state of unstable equilibrium, or rather is forever passing between the two, and evolving the myriad forms of life in the passage. It is hard to think of the process as the work of the physical and chemical forces of inorganic nature, without supplementing them with a new and different force.

The forces of life are constructive forces, and they are operative in a world of destructive or disintegrating forces which oppose them and which they overcome. The physical and chemical forces of dead matter are at war with the forces of life, till life overcomes and uses them.

The mechanical forces go on repeating or dividing through the same cycles forever and ever, seeking a stable condition, but the vital force is inventive and creative and constantly breaks the repose that organic nature seeks to impose upon it.

External forces may modify a body, but they cannot develop it unless there is something in the body waiting to be developed, craving development, as it were. The warmth and moisture in the soil act alike upon the grains of sand and upon the seed-germs; the germ changes into something else, the sand does not. These agents liberate a force in the germ that is not in the grain of sand. The warmth of the brooding fowl does not spend itself upon mere passive, inert matter (unless there is a china egg in the nest), but upon matter straining upon its leash, and in a state of expectancy. We do not know how the activity of the molecules of the egg differs from the activity of the molecules of the pebble, under the influence of warmth, but we know there must be a difference between the interior movements of organized and unorganized matter.

Life lifts inert matter up into a thousand varied and beautiful forms and holds it there for a season,—holds it against gravity and chemical affinity, though you may say, if you please, not without their aid,—and then in due course lets go of it, or abandons it, and lets it fall back into the great sea of the inorganic. Its constant tendency is to fall back; indeed, in animal life it does fall back every moment; it rises on the one hand, serves its purpose of life, and falls back on the other. In going through the cycle of life the mineral elements experience some change that chemical analysis does not disclose—they are the more readily absorbed again by life. It is as if the elements had profited in some way under the tutelage of life. Their experience has been a unique and exceptional one. Only a small fraction of the sum total of the inert matter of the globe can have this experience. It must first go through the vegetable cycle before it can be taken up by the animal. The only things we can take directly from the inorganic world are water and air; and the function of water is largely a mechanical one, and the function of air a chemical one.

I think of the vital as flowing out of the physical, just as the psychical flows out of the vital, and just as the higher forms of animal life flow out of the lower. It is a far cry from man to the dumb brutes, and from the brutes to the vegetable world, and from the vegetable to inert matter; but the germ and start of each is in the series below it. The living came out of the not-living. If life is of physico-chemical origin, it is so by transformations and translations that physics cannot explain. The butterfly comes out of the grub, man came out of the brute, but, as Darwin says, "not by his own efforts," any more than the child becomes the man by its own efforts.

The push of life, of the evolutionary process, is back of all and in all. We can account for it all by saying the Creative Energy is immanent in matter, and this gives the mind something to take hold of.

II

According to the latest scientific views held on the question by such men as Professor Loeb, the appearance of life on the globe was a purely accidental circumstance. The proper elements just happened to come together at the right time in the right proportions and under the right conditions, and life was the result. It was an accident in the thermal history of the globe. Professor Loeb has lately published a volume of essays and addresses called "The Mechanistic Conception of Life," enforcing and illustrating this view. He makes war on what he terms the metaphysical conception of a "life-principle" as the key to the problem, and urges the scientific conception of the adequacy of mechanico-chemical forces. In his view, we are only chemical mechanisms; and all our activities, mental and physical alike, are only automatic responses to the play of the blind, material forces of external nature. All forms of life, with all their wonderful adaptations, are only the chance happenings of the blind gropings and clashings of dead matter: "We eat, drink, and reproduce [and, of course, think and speculate and write books on the problems of life], not because mankind has reached an agreement that this is desirable, but because, machine-like, we are compelled to do so!"

He reaches the conclusion that all our inner subjective life is amenable to physico-chemical analysis, because many cases of simple animal instinct and will can be explained on this basis—the basis of animal tropism. Certain animals creep or fly to the light, others to the dark, because they cannot help it. This is tropism. He believes that the origin of life can be traced to the same physico-chemical activities, because, in his laboratory experiments, he has been able to dispense with the male principle, and to fertilize the eggs of certain low forms of marine life by chemical compounds alone. "The problem of the beginning and end of individual life is physico-chemically clear"—much clearer than the first beginnings of life. All individual life begins with the egg, but where did we get the egg? When chemical synthesis will give us this, the problem is solved. We can analyze the material elements of an organism, but we cannot synthesize them and produce the least spark of living matter. That all forms of life have a mechanical and chemical basis is beyond question, but when we apply our analysis to them, life evaporates, vanishes, the vital processes cease. But apply the same analysis to inert matter, and only the form is changed.

Professor Loeb's artificially fathered embryo and starfish and sea-urchins soon die. If his chemism could only give him the mother-principle also! But it will not. The mother-principle is at the very foundations of the organic world, and defies all attempts of chemical synthesis to reproduce it.

It would be presumptive in the extreme for me to question Professor Loeb's scientific conclusions; he is one of the most eminent of living experimental biologists. I would only dissent from some of his philosophical conclusions. I dissent from his statement that only the mechanistic conception of life can throw light on the source of ethics. Is there any room for the moral law in a world of mechanical determinism? There is no ethics in the physical order, and if humanity is entirely in the grip of that order, where do moral obligations come in? A gun, a steam-engine, knows no ethics, and to the extent that we are compelled to do things, are we in the same category. Freedom of choice alone gives any validity to ethical consideration. I dissent from the idea to which he apparently holds, that biology is only applied physics and chemistry. Is not geology also applied physics and chemistry? Is it any more or any less? Yet what a world of difference between the two—between a rock and a tree, between a man and the soil he cultivates. Grant that the physical and the chemical forces are the same in both, yet they work to such different ends in each. In one case they are tending always to a deadlock, to the slumber of a static equilibrium; in the other they are ceaselessly striving to reach a state of dynamic activity—to build up a body that hangs forever between a state of integration and disintegration. What is it that determines this new mode and end of their activities?

In all his biological experimentation, Professor Loeb starts with living matter and, finding its processes capable of physico-chemical analysis, he hastens to the conclusion that its genesis is to be accounted for by the action and interaction of these principles alone.

In the inorganic world, everything is in its place through the operation of blind physical forces; because the place of a dead thing, its relation to the whole, is a matter of indifference. The rocks, the hills, the streams are in their place, but any other place would do as well. But in the organic world we strike another order—an order where the relation and subordination of parts is everything, and to speak of human existence as a "matter of chance" in the sense, let us say, that the forms and positions of inanimate bodies are matters of chance, is to confuse terms.

Organic evolution upon the earth shows steady and regular progression; as much so as the growth and development of a tree. If the evolutionary impulse fails on one line, it picks itself up and tries on another, it experiments endlessly like an inventor, but always improves on its last attempts. Chance would have kept things at a standstill; the principle of chance, give it time enough, must end where it began. Chance is a man lost in the woods; he never arrives; he wanders aimlessly. If evolution pursued a course equally fortuitous, would it not still be wandering in the wilderness of the chaotic nebulÆ?

III

A vastly different and much more stimulating view of life is given by Henri Bergson in his "Creative Evolution." Though based upon biological science, it is a philosophical rather than a scientific view, and appeals to our intuitional and imaginative nature more than to our constructive reason. M. Bergson interprets the phenomena of life in terms of spirit, rather than in terms of matter as does Professor Loeb. The word "creative" is the key-word to his view. Life is a creative impulse or current which arose in matter at a certain time and place, and flows through it from form to form, from generation to generation, augmenting in force as it advances. It is one with spirit, and is incessant creation; the whole organic world is filled, from bottom to top, with one tremendous effort. It was long ago felicitously stated by Whitman in his "Leaves of Grass," "Urge and urge, always the procreant urge of the world."

This conception of the nature and genesis of life is bound to be challenged by modern physical science, which, for the most part, sees in biology only a phase of physics; but the philosophic mind and the trained literary mind will find in "Creative Evolution" a treasure-house of inspiring ideas, and engaging forms of original artistic expression. As Mr. Balfour says, "M. Bergson's 'Evolution CrÉatrice' is not merely a philosophical treatise, it has all the charm and all the audacities of a work of art, and as such defies adequate reproduction."

It delivers us from the hard mechanical conception of determinism, or of a closed universe which, like a huge manufacturing plant, grinds out vegetables and animals, minds and spirits, as it grinds out rocks and soils, gases and fluids, and the inorganic compounds.

With M. Bergson, life is the flowing metamorphosis of the poets,—an unceasing becoming,—and evolution is a wave of creative energy overflowing through matter "upon which each visible organism rides during the short interval of time given it to live." In his view, matter is held in the iron grip of necessity, but life is freedom itself. "Before the evolution of life ... the portals of the future remain wide open. It is a creation that goes on forever in virtue of an initial movement. This movement constitutes the unity of the organized world—a prolific unity, of an infinite richness, superior to any that the intellect could dream of, for the intellect is only one of its aspects or products."

What a contrast to Herbert Spencer's view of life and evolution! "Life," says Spencer, "consists of inner action so adjusted as to balance outer action." True enough, no doubt, but not interesting. If the philosopher could tell us what it is that brings about the adjustment, and that profits by it, we should at once prick up our ears. Of course, it is life. But what is life? It is inner action so adjusted as to balance outer action!

A recent contemptuous critic of M. Bergson's book, Hugh S. R. Elliot, points out, as if he were triumphantly vindicating the physico-chemical theory of the nature and origin of life, what a complete machine a cabbage is for converting solar energy into chemical and vital energy—how it takes up the raw material from the soil by a chemical and mechanical process, how these are brought into contact with the light and air through the leaves, and thus the cabbage is built up. In like manner, a man is a machine for converting chemical energy derived from the food he eats into motion, and the like. As if M. Bergson, or any one else, would dispute these things! In the same way, a steam-engine is a machine for converting the energy latent in coal into motion and power; but what force lies back of the engine, and was active in the construction?

The final question of the cabbage and the man still remains—Where did you get them?

You assume vitality to start with—how did you get it? Did it arise spontaneously out of dead matter? Mechanical and chemical forces do all the work of the living body, but who or what controls and directs them, so that one compounding of the elements begets a cabbage, and another compounding of the same elements begets an oak—one mixture of them and we have a frog, another and we have a man? Is there not room here for something besides blind, indifferent forces? If we make the molecules themselves creative, then we are begging the question. The creative energy by any other name remains the same.

IV

If life itself is not a force or a form of energy, yet behold what energy it is capable of exerting! It seems to me that Sir Oliver Lodge is a little confusing when he says in a recent essay that "life does not exert force—not even the most microscopical force—and certainly does not supply energy." Sir Oliver is thinking of life as a distinct entity—something apart from the matter which it animates. But even in this case can we not say that the mainspring of the energy of living bodies is the life that is in them?

Apart from the force exerted by living animal bodies, see the force exerted by living plant bodies. I thought of the remark of Sir Oliver one day not long after reading it, while I was walking in a beech wood and noted how the sprouting beechnuts had sent their pale radicles down through the dry leaves upon which they were lying, often piercing two or three of them, and forcing their way down into the mingled soil and leaf-mould a couple of inches. Force was certainly expended in doing this, and if the life in the sprouting nut did not exert it or expend it, what did?

When I drive a peg into the ground with my axe or mallet, is the life in my arm any more strictly the source (the secondary source) of the energy expended than is the nut in this case? Of course, the sun is the primal source of the energy in both cases, and in all cases, but does not life exert the force, use it, bring it to bear, which it receives from the universal fount of energy?

Life cannot supply energy de novo, cannot create it out of nothing, but it can and must draw upon the store of energy in which the earth floats as in a sea. When this energy or force is manifest through a living body, we call it vital force; when it is manifest through a mechanical contrivance, we call it mechanical force; when it is developed by the action and reaction of chemical compounds, we call it chemical force; the same force in each case, but behaving so differently in the one case from what it does in the other that we come to think of it as a new and distinct entity. Now if Sir Oliver or any one else could tell us what force is, this difference between the vitalists and the mechanists might be reconciled.

Darwin measured the force of the downward growth of the radicle, such as I have alluded to, as one quarter of a pound, and its lateral pressure as much greater. We know that the roots of trees insert themselves into seams in the rocks, and force the parts asunder. This force is measurable and is often very great. Its seat seems to be in the soft, milky substance called the cambium layer under the bark. These minute cells when their force is combined may become regular rock-splitters.

One of the most remarkable exhibitions of plant force I ever saw was in a Western city where I observed a species of wild sunflower forcing its way up through the asphalt pavement; the folded and compressed leaves of the plant, like a man's fist, had pushed against the hard but flexible concrete till it had bulged up and then split, and let the irrepressible plant through. The force exerted must have been many pounds. I think it doubtful if the strongest man could have pushed his fist through such a resisting medium. If it was not life which exerted this force, what was it? Life activities are a kind of explosion, and the slow continued explosions of this growing plant rent the pavement as surely as powder would have done. It is doubtful if any cultivated plant could have overcome such odds. It required the force of the untamed hairy plant of the plains to accomplish this feat.

That life does not supply energy, that is, is not an independent source of energy, seems to me obvious enough, but that it does not manifest energy, use energy, or "exert force," is far from obvious. If a growing plant or tree does not exert force by reason of its growing, or by virtue of a specific kind of activity among its particles, which we name life, and which does not take place in a stone or in a bar of iron or in dead timber, then how can we say that any mechanical device or explosive compound exerts force? The steam-engine does not create force, neither does the exploding dynamite, but these things exert force. We have to think of the sum total of the force of the universe, as of matter itself, as a constant factor, that can neither be increased nor diminished. All activity, organic and inorganic, draws upon this force: the plant and tree, as well as the engine and the explosive—the winds, the tides, the animal, the vegetable alike. I can think of but one force, but of any number of manifestations of force, and of two distinct kinds of manifestations, the organic and the inorganic, or the vital and the physical,—the latter divisible into the chemical and the mechanical, the former made up of these two working in infinite complexity because drawn into new relations, and lifted to higher ends by this something we call life.

We think of something in the organic that lifts and moves and redistributes dead matter, and builds it up into the ten thousand new forms which it would never assume without this something; it lifts lime and iron and silica and potash and carbon, against gravity, up into trees and animal forms, not by a new force, but by an old force in the hands of a new agent.

The cattle move about the field, the drift boulders slowly creep down the slopes; there is no doubt that the final source of the force is in both cases the same; what we call gravity, a name for a mystery, is the form it takes in the case of the rocks, and what we call vitality, another name for a mystery, is the form it takes in the case of the cattle; without the solar and stellar energy, could there be any motion of either rock or beast?

Force is universal, it pervades all nature, one manifestation of it we call heat, another light, another electricity, another cohesion, chemical affinity, and so on. May not another manifestation of it be called life, differing from all the rest more radically than they differ from one another; bound up with all the rest and inseparable from them and identical with them only in its ultimate source in the Creative Energy that is immanent in the universe? I have to think of the Creative Energy as immanent in all matter, and the final source of all the transformations and transmutations we see in the organic and the inorganic worlds. The very nature of our minds compels us to postulate some power, or some principle, not as lying back of, but as active in, all the changing forms of life and nature, and their final source and cause.

The mind is satisfied when it finds a word that gives it a hold of a thing or a process, or when it can picture to itself just how the thing occurs. Thus, for instance, to account for the power generated by the rushing together of hydrogen and oxygen to produce water, we have to conceive of space between the atoms of these elements, and that the force generated comes from the immense velocity with which the infinitesimal atoms rush together across this infinitesimal space. It is quite possible that this is not the true explanation at all, but it satisfies the mind because it is an explanation in terms of mechanical forces that we know.

The solar energy goes into the atoms or corpuscles one thing, and it comes out another; it goes in as inorganic force, and it comes out as organic and psychic. The change or transformation takes place in those invisible laboratories of the infinitesimal atoms. It helps my mental processes to give that change a name—vitality—and to recognize it as a supra-mechanical force. Pasteur wanted a name for it and called it "dissymmetric force."

We are all made of one stuff undoubtedly, vegetable and animal, man and woman, dog and donkey, and the secret of the difference between us, and of the passing along of the difference from generation to generation with but slight variations, may be, so to speak, in the way the molecules and atoms of our bodies take hold of hands and perform their mystic dances in the inner temple of life. But one would like to know who or what pipes the tune and directs the figures of the dance.

In the case of the beechnuts, what is it that lies dormant in the substance of the nuts and becomes alive, under the influence of the warmth and moisture of spring, and puts out a radicle that pierces the dry leaves like an awl? The pebbles, though they contain the same chemical elements, do not become active and put out a radicle.

The chemico-physical explanation of the universe goes but a little way. These are the tools of the creative process, but they are not that process, nor its prime cause. Start the flame of life going, and the rest may be explained in terms of chemistry; start the human body developing, and physiological processes explain its growth; but why it becomes a man and not a monkey—what explains that?