3 September 1919, Stuttgart
When we consider the human body, we must relate it to the physical sense-world that surrounds it and maintains it, for there is a constant interplay between the physical body and the world, through which it is sustained. When we look out into the physical sense-world around us, we perceive mineral beings, plant beings, animal beings. Our physical body is related to the beings of the minerals, plants and animals. But the peculiar nature of this relationship is not immediately evident to superficial observation; we must penetrate deeply into the character of the kingdoms of nature if we are to understand this relationship.
When we regard the human being as physical body, what we first perceive is his solid bony frame and his muscles. When we penetrate further into him we perceive the circulation of the blood with the organs which belong to it. We perceive the breathing, we perceive the processes of nourishment. We see how, the organs are built up out of the most varied vascular forms — as they are called in natural science. We perceive brain and nerves, the sense organs. We have now to co-ordinate these various organs of the human being and their functions with the external world.
Let us begin with that part of the human being which at first appears to be the most perfect (we have already seen how the matter really stands), let us begin with the brain and nervous system which is closely linked with the sense organs. This part of the human organisation shows the longest earthly evolution behind it, so that it has passed beyond the form which the animal world has developed. Man has passed through the animal world, as it were, in relation to this, his head system, and he has gone beyond the animal system to the real human system — which indeed is most clearly expressed in the formation of the head.
Now we spoke yesterday of how far the formation of the head takes part in individual human evolution, how far the shape, the form of the human body proceeds from the forces which are to be found in the head. And we saw how the work of the head reaches a kind of conclusion with the change of teeth towards the seventh year. We should make clear to ourselves what really happens through the interplay between the human head, the chest organs and the limb organs. We should answer the question: what does the head really do in carrying out its work in connection with the chest-trunk system and the limb-system? It is continually forming, shaping. Our life really consists in this, that in the first seven years an intense forming force streams from the head right down into the physical form; and the head continues its aid by preserving the form, by ensouling it, by spiritualising it.
The head is involved in shaping the human form. But does the head build up our truly human shape? No, indeed it does not. You must learn to accept the view that your head is constantly trying, in secret, to make something different out of you from what you are. There are times when the head would like to shape you so that you would look like a wolf; at other times it would like to shape you so that you would look like a lamb. Then again, so that you would look like a serpent; it would like to make you into a serpent, a dragon.
All the shapes which your head really designs in you, you find spread out in nature, in the different animal forms. If you look at the animal kingdom you can say to yourself: that am I; but when the head produces the wolf form, for instance, my trunk system and my limb system constantly do me the favour of changing this wolf form into the human form. They are perpetually within themselves overcoming the animal element. They so master it as to prevent it attaining complete existence within them, they metamorphose it, they transform it. Thus the human being has a relationship to the animal world around him through the head system. But it is such that he is continually carried beyond the animal world in the creation of his body. What, then, really remains in you? You can look at a human being. Imagine that you have a man before you: you can make this interesting observation. You can say: there is the man. There is his head, and in the head a wolf is actually stirring, but it does not develop into a wolf; it is immediately dissolved by the trunk and the limbs. In the head a lamb is actually stirring; it is dissolved by the trunk and the limbs.
The animal forms are continually moving supersensibly in the human being, and are being dissolved. What would happen if there were a super-sensible photographer who could retain this process, who could preserve this process on a photographic plate, or on a series of photographic plates? What should we see on these plates? We should then see the thoughts of man. These thoughts of the human being are indeed a super-sensible correlate to that which does not come to expression in the sense-world. This continual metamorphosis out of the animal, streaming down from the head, is not expressed in the senses, but it works in man supersensibly as the process of thought. In reality this is present as a super-sensible process. Your head is not merely the lazy-bones on your shoulders, it is that which would really like to maintain you in animality. It gives you the forms of the whole animal kingdom; it would like animal kingdoms continually to arise. But by means of your trunk and your limbs you prevent a whole animal kingdom from arising through you in the course of your life: you transform this animal kingdom into your thoughts. Such is our relationship to the animal kingdom. We allow this animal kingdom to arise supersensibly within us, and then we do not allow it to come to sensible reality, but hold it back in the super-sensible. The trunk and the limbs do not allow these evolving animal forms to enter their sphere. If the head has too strong an inclination to produce something of this animal nature, the remaining organism struggles against accepting it, and then the head has to resort to migraine or to some similar head complaint in order to exterminate it again.
The trunk system is also related to our environment — not in this case, to the animal world but to the whole range of the plant kingdom. There is a mysterious connection between the trunk system of man, the chest system, and the plant world. The most important processes in the circulation of the blood, also in breathing and nourishment, all take place in the chest or trunk system. All these processes are in active interchange with what takes place outside in the physical sense-world of the plants, but in a very special way.
Let us first take the breathing. What does a man do in breathing? You know that he takes in oxygen, and through his life processes he changes oxygen into carbon dioxide by connecting it with carbon. Carbon is in the organism from the transformed foodstuffs. This carbon takes up the oxygen, and carbon dioxide gas arises through the union of the oxygen with the carbon. Now when man has the carbon dioxide within him it would be a splendid opportunity for him not to let it out, but to keep it there. And if he could free the carbon again from the oxygen, what would happen? Let us say that a man breathes in oxygen through his life processes, and allows it to form carbon dioxide by uniting with carbon; if now he were in a position to separate off the oxygen again within, and to work upon the carbon, what would then arise in the man? The plant world. The whole vegetable kingdom would suddenly grow up in man. It really could grow there.
For if you consider a plant, what does it do? Of course it does not breathe in oxygen in the same regular way as man, but it assimilates carbon dioxide. By day the plant is bent on getting carbon dioxide, it gives up oxygen. It would be bad if it did not do this; for then neither we nor the animals would have it. But the plant retains carbon, and out of this it forms starch and sugar and everything else it consists of. From this it builds up its whole organism. The plant world arises by building itself up from carbon which plants in their process of assimilation separate off from the carbon dioxide. When you look at the plant world, it is metamorphosed carbon, which is separated off by the process of assimilation, and this process corresponds to the human process of breathing. The plants also breathe to a certain extent, but it is different from the breathing process in man. The plant does breathe a little, especially in the night, but to say that plants can really breathe shows a superficial observation, and is like saying: “Here is a razor, I will cut meat with it.” The process of breathing in plants is different from the process of breathing in men and in animals, just as the razor is different from the table knife. The human process of breathing corresponds in the plants to the reverse process, that of assimilation.
From this you will understand that if you continued in yourself the process by which carbon dioxide has arisen, that is, if the oxygen could be given up again and the carbon dioxide could be transformed into carbon, as is done by nature in the world around you, then you could let the whole vegetable world grow up in you. You would have the materials for this within yourself and you could bring it about that you would suddenly blossom forth as plant world. You would disappear and the whole plant world would arise. This capacity of producing a plant world is indeed inherent in man, but he does not allow it to come to this point. His chest system has a strong inclination continually to produce the plant world. Head and limbs do not allow this to happen, they defend themselves against it. And so man drives out the carbon dioxide, and does not allow the plant kingdom to arise within himself. He allows the plant kingdom to arise out of the carbon dioxide in the outside world.
This is a remarkable interplay between the trunk-chest system and the sense physical world around us; for outside there is the kingdom of the vegetables, and the human being is continually having to prevent the process of vegetation from arising within him; if it does arise he must immediately send it out again so that he may not become a plant. Thus, in so far as the chest-trunk system is concerned, man is able to create the counter kingdom to the plant world. If you conceive the plant kingdom as positive, then man produces the negative of the plant kingdom. He produces, as it were, reversed plant kingdom.
What happens when the plant kingdom begins to behave badly in him, and head and limbs have not the power to nip it in the bud, to drive it out? Then the man becomes ill. The internal illnesses which come from the trunk system are ultimately due to this, that a man is too weak to check the plant-like growth as soon as it begins to arise within him. The moment there arises in us even a vestige of plant-like nature, the moment we fail to ensure that the plant kingdom which endeavours to grow in us shall be cast out to form its kingdom outside us — in that moment we become ill. And thus the essential nature of disease must be sought in this tendency towards plant growth in man. Naturally it is not true plants that grow, for after all the human interior is not a very pleasant surrounding for a lily. But through a weakening of the other systems of the trunk there can result a tendency towards the growth of the plant kingdom, and then man becomes ill.
Thus if we look at the whole plant world of man's environment we must say to ourselves: in a certain sense the plant kingdom presents pictures of all our illnesses. It is the wonderful secret in man's relationship to surrounding nature that not only (as we have shown on other occasions) do the plants represent pictures of his development up to adolescence, but in the plants around him, especially in so far as these plants are fruit bearing, he can see the pictures of his illnesses. This is a thing we may perhaps not like to hear, because it is natural to love the plant world aesthetically; and, when the plant unfolds in the world outside, this aesthetic attitude is justified. But the moment the plant seeks to unfold within man, the moment vegetation sets up within him, then what works outside in the many-coloured beautiful plant kingdom, works in man as the cause of illness. Medicine will become a science when it is able to show how each individual illness corresponds with some form in the plant world. Actually it is true that when man breathes out carbonic acid gas, he is, for the sake of his own existence, constantly breathing out the whole of the plant world which wants to arise in him. Hence it need not seem strange to you that when the plant begins to extend — beyond its ordinary plant nature, and produces poisons, these poisons are bound up with the processes of man's health and sickness. At the same time all this is bound up with the normal process of nourishment.
Indeed, nourishment, like the process of breathing, takes place in the chest-trunk system, at least in its initial stages, and must be considered in exactly the same way as breathing. In the processes of nourishment man also takes in substances from the world around him, but he does not leave them as they are; he changes them. He changes them with the help of the oxygen which he breathes in. As man transforms the substances taken up in nourishment, they combine with oxygen. This appears as a process of combustion, and it looks as though the human being were constantly burning within. This moreover is what natural science frequently says, that a process of combustion is going on in the human being. But it is not true. What takes place in the human being is no true process of combustion, but is a process of combustion (notice this carefully) — it is a process of combustion which lacks both beginning and end. It is merely the middle stage of the process of combustion; it lacks the beginning and end of it. The beginning and the end of the process of combustion must never take place in the human body, only the intervening part. It is destructive to the human being if the first stages of the process of combustion, such as take place in the forming of fruit, are carried on in the human organism; for instance when a man eats unripe fruit. The human being cannot carry out this initial process similar to combustion. The human being cannot endure this in himself, it makes him ill. And if he can eat a great deal of unripe fruit, like strong country people for instance, then he must be very closely related to the nature around him, for otherwise he would not be able to digest unripe apples and pears as he can the fruit which has been ripened by the sun. Thus it is only the middle process which he can carry out. In the processes of digestion the human being can only take part in the middle stage of all the combustion processes. Again, if the process is carried to its conclusion, to where, in the outer world, the ripe fruit would rot, the human being can have no part in it. Thus he cannot take part in the end stage either. He must excrete the food stuffs before this stage is reached. It is actually the case that the human being does not carry on the processes of nature as they take place around him, but he only goes through the middle part; within himself he cannot fulfil the beginning or the end.
Now we will look at something most remarkable. Consider breathing. It is the opposite to everything which takes place in the plant world around us. It is in a certain way the anti-plant kingdom. The breathing of man is the anti-plant kingdom, and it is inwardly connected with the process of nourishment which is the middle stage of the combustion process of the outer world. You see, there are two processes in our bodily chest-trunk system; this anti-plant process, which takes place through the breathing, is always at work in connection with the central portion of the other external processes. These two are constantly interrelated in their work. Here, you see, body and soul are combined. That which takes place through the breathing unites with the remaining nature processes, which however, as they take place in man, represent only the middle portion of Nature's processes. And this means that the soul life, which is the anti-plant process, unites with the humanised bodily life, namely the middle portion of the processes of Nature. Science may well search for a long time for the mutual relationship between body and soul unless it seeks it in the mysterious connection between the breath, which has become soul, and the middle part of the processes of Nature, which has become body. These processes of Nature neither arise nor decay in man. They take their rise outside him and only after he has excreted them should they decompose. Man unites himself in body with a central part only of the processes of Nature; and in the breathing processes he fills these Nature processes with soul.
Here there arises that delicate inter-weaving of processes to which the medicine and the hygiene of the future will have to devote very special attention. The hygiene of the future will have to ask: how are the different degrees of warmth interrelated in the world outside? How does warmth act when passing from a cooler place to a warmer, and vice versa? There are warmth processes at work in the external world; how does such a warmth process act in the human organism when this organism is placed into it? Man finds an interplay of air and water in the external process of vegetation. He will have to study how that works on the human being when he is placed in it, and so forth.
With regard to things of this kind the medicine of to-day has only made the very smallest beginning, scarcely even a beginning. When there is an illness the medicine of to-day sets the greatest value on finding the bacilli, the kind of bacteria which causes the illness. Then, when it has found that, it is satisfied. But it is much more important to know how it comes about that, at a particular moment of a man's life, he is prone to develop some suggestion of a vegetative process, so that the bacilli scent a comfortable place of sojourn. The important thing is to keep our bodily constitution in such a condition that it is not an agreeable hostelry for all vegetable pests; if we do this, these gentlemen will not be able to bring about too great a devastation in us.
Now there remains the question: in considering the human being physically in his relation to the outer world, what part do the bony skeleton and muscles really play in the human life process as a whole?
We now come to something which, in the science of today, is hardly regarded at all; but it is absolutely essential that you should grasp it if you want to understand the human being. Please notice what happens when you bend your arm. Through the contraction of the muscle which bends your forearm you are bringing into play a machine-like process. Imagine that it simply comes about in the following way. First of all, you have a position where upper and lower arm (or two corresponding laths or poles) lie in one and the same direction (drawing a).
Then this position (drawing b) represents the bent arm.
Suppose now you stretch a band (c) and then begin to roll it up. This lath here would carry out the movement indicated by the arrow in the drawing. It is a thoroughly machine-like movement. You also carry out mechanical movements of this kind when you bend your knee and when you walk. For in walking the whole mechanism of your body is brought into continuous movement, and forces are continuously at work. They are pre-eminently forces of leverage, but forces are actually at work. Imagine to yourselves that by some kind of photographic trick you could arrange that, when a man was walking, all the forces and nothing of the man, should be photographed; I mean the forces which he applies to raise his knee, to put it down again, to bring the other leg in front.
Nothing of the man would be photographed except the forces. If in the photograph you could see these forces developing, it would be a photograph of a shadow, and even in walking itself you would have a whole series of shadows. You make a great mistake if you believe that you live with your ego in your muscles and flesh. Even when you are awake you do not live with your ego in your muscles and flesh, you live with your ego principally in the shadow which you photograph in this way, in the forces used by your body when it moves. Grotesque though it may sound, when you sit down and press your back against the back of the chair, you live with your ego in the force which is developed in this pressure.
When you stand up you live in the force with which your feet press the ground. You live continually in forces. It is not in the least true that we live with our ego in our visible body. We live with our ego in forces. We only carry our visible body about with us; drag it along with us during our physical earth life until death. Even in the waking condition we live only in a force body. And what does this force body really do? It continually sets itself a peculiar task.
It is true, is it not, that when you are eating you take in all kinds of mineral substances? Even if you do not make your soup very salty, the salt is nevertheless in the food, and you are taking in mineral substance. It is necessary that you should take in mineral substance. What do you do with it? Your head cannot do much with it. Neither can your trunk-chest system. But your limb system prevents these mineral substances from taking on their own crystal forms in you. If you did not develop the forces of your limb system, then when you ate salt you would become a salt crystal. Your limb system, your skeleton and your muscular system have a constant tendency to work against the mineral formation of the earth, that is, to dissolve the minerals. The forces which dissolve the minerals in the human being come from the limb system. If a morbid disturbance goes beyond the merely vegetable process, that is, if the body has the tendency not only to allow plant life to appear, but also the process of mineral crystallisation, then a more severe, a more destructive form of illness is set up; for instance, diabetes. Then the body is not able to apply the force of the limbs which it receives from the universe to dissolve the mineral. In reality it should be constantly dissolving the mineral. If to-day men cannot master those forms of illness which arise from unhealthy mineralisation in the human body, it is largely because we cannot adequately apply the antidote which we must find in connection with the sense organs, the brain, the nerve fibres, etc. In order to overcome gout, diabetes and similar illnesses, we ought to be able to use in some form the apparent substances (* German: Scheinstoge) — I call them apparent substances advisedly — we ought to use this decaying matter, which is in the sense organs, in the brain and nerves. What is really healing for humanity in this sphere will only be reached when the relationship between man and nature has been thoroughly investigated from the point of view which I have given you to-day.
The human body is only to be explained when we know the processes that take place in it: when we know that the human being must dissolve within him the mineral, must reverse within him the plant kingdom, must raise above him, that is, must spiritualise, the animal kingdom. And all that a teacher ought to know about the evolution of the body has — as its foundation — what I have placed before you here in these anthropological, anthroposophical considerations.