Deep in every one of us there is a passion of desire to understand, just as there is of desire to enjoy and of desire to be somehow or other 'in the right.' I say deep in us, because we are in the habit either of burying these desires beneath a pretence of satisfying them or else of diverting our attention from them and thus letting them sink out of sight. So we live our life in the pursuit of other ends than those likely to be reached through understanding and rapture and righteousness. We falsify ourselves and our desires; yet unless we ruin the life within us they persist, waiting their hour.

There are moments when it becomes almost impossible for any man who has seen something of the marvel of every-day affairs to believe that he might spend time in vain if he were to try to convince his next-door neighbour that there was anything hard to understand about the crooking of a finger. Yet that is his experience when he tries. Just because every man who has a healthy finger in a healthy body and a healthy mind can and does crook it, there is nothing to wonder at. The whole affair is plain; it is familiar, happens every day. Familiarity lulls to sleep both the desire for understanding, and the sense of not understanding.

Consequently there is little that should provoke surprise on our part in the fact that not one man in (say) ten thousand is consciously puzzled by any of the deeper problems of life, not one in (say) a hundred thousand has his imagination either stirred or stunned by the green blades of the corn, the leaves of the tree, the grass in his fields or the sheep and cows that are eating it. There is nothing new about all this, nothing strange; it is familiar—therefore it is understood or there is nothing that calls for understanding. Yet in these green blades and leaves is the junction-point between the living and the not-living, between the plant and animal on the one hand and what we call 'inert matter' on the other, between the radiant energy of the sun and ourselves. And we do not understand, nobody understands, how that junction-point works. It is called chlorophyll; it is found in little living bodies called chloroplasts; and it is wonderful 'beyond all whooping'. Yet we do not even whoop. We do not get even thus far. We are not surprised, we are not enraptured. The thing is at once both too familiar and too obscure for us.

We cannot do away with the familiarity; but at least, as reasonable beings possessed of that passion of desire which is a cry of the spirit within us and which we so often do our utmost to suppress, it will be well for us to make an attempt to find out how and even why this green stuff of the plant is so highly distinguished among the wonders of the world.

But first let us ask ourselves a searching and pertinent question—let us ask ourselves what it means to be alive. A man is alive, but so are the cells of his own blood, so is the grass in the fields, so are the small jellies we call amoebae and the still smaller rods and specks we call bacteria and 'germs.' Can we say anything about life that will at once fit these and distinguish them from all else that does not live, accepting for the moment the distinction between living and not-living that we ordinarily make?

There are several things that we may say about them. For example, they grow. But a crystal grows and so does a heap of sand. There are, then, different ways of growing. The sand heap grows when the wind scatters particles of sand over it or the sea drives them; or the river, or a small boy with a barrow, deposits them. It grows by mere addition. The crystal grows without any such aid and in a different way. If you want to see an alum-crystal grow you must offer it more alum, dissolved; you must offer it its own material and it will then grow without other help. It will grow by what we may call formative accretion. On the other hand the grass and the corn and the trees grow neither by mere addition nor by formative accretion, but by converting, assimilating and incorporating nitrogen, carbon, and so on, compounded either by their own effort or by the micro-organisms of the soil. They are magicians, these live creatures. And of all their magic the magic of their green leaves is chief in our eyes. For it takes the carbonic acid of the air, a stable compound of one atom of carbon with two of oxygen, and tears it to pieces, using for that enormous work the radiant energy of the sun. This carbon, now potent with the potency of the sun, is then united with other elements to make sugars that nourish the tissues of the plant. In these sugars power is stored as it is stored in an explosive like dynamite or trinitrotoluol. But in the plant, power is under strict control; it is liberated by degrees as it is wanted and is replaced as it is used; it is controlled, used, replaced in a discriminating, selective and determining way. The ability to make use of physical power, within a body, in this discriminating, selective and determining way and thus to grow is (among other things) what is meant by being alive.

The chemist in his laboratory can make explosives, chemical compounds that will easily break down and in breaking down will liberate, for good or ill, great power. He makes nitroglycerin and trinitrotoluol. He can also make very elaborate and more stable compounds than a plant makes, for instance, indigo or madder-red, though for such as these he does not usually begin like the plant with chemical elements; he begins half way—with lesser compounds, ready made—and thus, or even sometimes by building up from the bottom, from elements, like the plant, he makes what are known as 'organic' substances of many sorts and uses. Is it possible that he will ever make that organic substance protoplasm, the life-jelly of living things? He has not done so yet. Suppose he did, suppose he went on from making indigo to make the indigo-maker itself. There is nothing of a chemical kind in the indigo-plant which his laboratory does not contain; there are just the carbon, nitrogen, oxygen, salts and the rest, with which he deals so successfully elsewhere. He has all the materials to hand. Why should he not make its living stuff? Again, suppose he did, for perhaps he will. What then? Will he have made life, as well as built up the material substance of a living thing? That is a question of questions.

We know life here only in association with its jelly. What is the character of that association? Granted that life depends on the jelly, in what way does it depend? If we can answer these questions we may know how to answer the one about the chemist's making or not making life, if and when he makes the jelly.

There are different ways of being dependent, as there are different ways of growing. The steam depends on the boiler and the boiler-fire. In this case the dependence is one of being produced. The boiler and its fire produce the steam. So we say, in the ordinary way of speaking of such things. Again—when I press the trigger of a rifle the bullet is shot out. I have only pressed the trigger; you can hardly say I have produced the bullet. What I have done is to release an explosive power that drives the bullet. That is another kind of dependence, dependence on the release of power. There may be still, there certainly have been, men who would tell you that life is produced by protoplasm as steam is produced by the boiler, or that it is released from a chemical compound by some chemical or physical trigger action. They might, once they did in large numbers, say that consciousness is produced by or released from the brain, and that this must be so because it depends upon the brain.

These two assertions, one about life and the other about consciousness, stand or fall together; and we can begin to see that they may be made to fall, as soon as we see that there is a third kind of dependence to be considered besides the dependence of the bullet and the steam. There is the dependence of light in a room on the existence of a window. Without window no light in that room; with window as much light as window permits to pass. There is a dependence of transmission, and transmission may occur in many wide and fundamentally differing ways. At a stroke you see the whole question and series of questions take on a new aspect. If the chemist makes life-jelly he may have made not something to produce or to release but something to transmit life. He may doubtless have imitated what there is good reason to think must have taken place on the earth's surface long ago and may indeed be taking place now; but in doing this he may only have made a material substance capable of allowing spiritually potent life to be manifest in it and to endow it with a share in promoting the purposes of life. He may have made for the peculiar potency of life a door of entrance to a house, or rather, since this house is not passive, to a body in which it and the body will be distinguishable as a living being, an example of life and matter living and at work together. Why not? The supposition of some such dependence of the superior power of life upon a body seems quite as reasonable, even at no more than a first glance, as the other suppositions made by men who do not acknowledge the specific character of life. And it accords far better with both knowledge and experience, when these are taken at their widest and their most profound. The other suppositions accord only with chosen parts of knowledge and chosen bits cut out of experience—the parts and bits cut out and chosen by the man who restricts himself to the specialism and the very right and proper superficiality of certain sciences. Even there they accord but ill, because in their inception they trespass beyond the borders of all science.

Living creatures are the subject of the mere biologist's merely scientific inquiry—not life. When a biologist, speaking as biologist, tries to tell us both that life is and what it is, he is philosophizing. Life is in fact an ultra-scientific problem. We have to call in philosophy before we can even state the problem. And when either the biologist or the physicist or the chemist talks of life as a mode of physical or chemical energy, or as a product of things, he is playing at philosophy, not soberly working at his science. The biologist shall teach us about living creatures, the physicist and the chemist about physical and chemical things and powers; but the philosopher must help us in our enquiry about life. And this, not because a man shall not be permitted to transgress boundaries we lay down, but because his chosen methods preclude his walking safely except within boundaries they themselves build up. Of every specialist this is true. We must transcend specialism if we would have 'all things, like the stars in heaven,' shed 'their light upon one another.'