The stream of physical matter as a whole, when it comes into an organ, runs against a resistance as it were. It cannot remain as it is. It must change itself. It is told by the organ, as we might say, "You cannot remain as you are. You must transform yourself." Let us suppose that such a substance goes into the liver. There it is told, "You must change yourself." A resistance is set up against it. To be further used it must become a different substance, and it must cast off certain portions. Thus it happens in our organism that resistance is perceived. Such resistances are perceived within the most diverse organs. It is only because secretion takes place at all in our organism, only because we have organs of secretion, that it is possible for our organism to be secluded within itself, to be a self-experiencing being. For only so can any being become conscious of its own inner life, through the fact that its own life meets with resistance. Thus we have in the processes of secretion processes important for human life—processes, in other words, by which the living organism secludes itself within itself. We would not be a being secluded within ourselves if such processes of secretion did not take place.

If air, water or food passed through us as though in a tube or hose, getting no resistance, we would have no consciousness of self as distinct from our surroundings—the situation that existed before the human being descended into material existence. What makes it possible to realize the inner life of the human organism are the processes of secretion.

Now let us look at the blood as one of the human organ systems. If it were to go through the human Ego unchanged, it could not be the instrument of the human Ego, what in the very highest sense enables us to be conscious of our own inner life. Only because the blood undergoes changes in its own inner life, and then goes back as something different—in other words, only because something is excreted from the changed blood—is it possible for us not only to have an Ego, but to experience it inwardly with the help of a physical-sensible instrument.

With the concept of excretion and its function in mind, Steiner then moves to the outermost boundary of our organism, its periphery, in order to carry the concept of self-awareness or self-enclosure to our outer extremity. It is necessary, confronting all the streams of our organism, that there should be one organ connected with this most extensive of all the processes of excretion—the skin. For it presents most directly to the view what we call essential in the human form. When we picture to ourselves that our organism can be inwardly conscious of its own life at its outermost periphery only because it has placed the organ of the skin where it confronts all its various streams, we are obliged to see the peculiar formation of our skin as an expression of the innermost force of our organism.

While Steiner does not mention it, there would seem to be in the phenomenon of perspiration an example of the evolutionary development of the earthbound Ego or self-consciousness (9 Brit 313, "perspiration"). While sweat glands are found in the majority of mammals (and apparently not in any lower animals), they constitute the primary means of heat dissipation only in certain hoofed animals and in primates, including humans. The nearer to the human being the animals got in their supersensible-world evolution before descending into materiality, the more they developed this essential tool of self-consciousness, sweat glands. Any dog owner in hot climates should know that a dog can suffer more from heat than a human if its panting is inadequate, because it loses little or no heat through perspiration. The ape is nearer to the human than the horse, but esotericism tells us that it was at the stage when the horse descended that the human, still in the spiritual world, gained by virtue of the horse's loss the possibility for intelligence—thus the human being's affinity for the horse even today. So the horse is about as low as significant perspiration occurs in the animal kingdom.

But in the fashioning of all of our organs of self-consciousness including the most visible, our skin, our own directly voluntary action is completely excluded. One can change the facial expression and, over time, have a certain influence within narrow limits upon the outer form of one's body through one's inner life between birth and death. But the most essential share in the forming of our body is not entrusted to our volition with the help of what reaches us through our consciousness. In this regard, Steiner compares the human being to a machine.

A machine is to be used for some intelligent activity, some activity that has a purpose. In order, however, for the machine to come into existence, it is necessary that activities be carried out which assemble the parts of the machine and give form to the whole. These activities must be similar to those later carried on by the machine itself. We must say, therefore, that when we observe a machine it is wholly and absolutely explicable on mechanical principles. But the fact that the machine is adapted to its purpose requires us to suppose that it came into existence through the activity of a mind which had thought out that purpose beforehand. This spiritual activity has withdrawn, to be sure, and does not need to be brought forward when we wish to explain the machine scientifically. Yet it is there, behind the machine, and first produced it.

So likewise can we say that, for the developing of our capacities and powers as human beings, we need above all those systems of forms lying within the molding of our organism. There must be behind this human form, however, forces that do the forming, which we can as little find in the already fashioned form as we find the builder of the machine in the machine itself. The human physical organism is, indeed, absolutely and entirely explainable out of its own physical laws, just as is the watch. Yet it does not follow from the fact that the watch can be explained by its own laws that the inventor was not behind it.

Therefore, when we think from the point of view of spiritual science, we have first to seek behind the form of the human being as a whole for the form-creative beings.

These beings are those of the hierarchies (see I-6), the Spirits of Will, Wisdom, Motion and Form, and their lower agencies (I-7). We may skip over Steiner's brief illustration of the activity of the Spirits of Form and Movement (Motion), which he concludes by stating the obvious, namely, that the activity of these spirits is not within the range of our normal consciousness. He poses the question, why is it not?

Our brain and spinal cord convey external impressions to the blood, thus inscribing them upon the instrument of the Ego so that the outer impressions are transferred to it. On the other side, the sympathetic nervous system stands guard over the inner cosmic system to keep its processes from approaching as far as the blood. The biblical version describing the hiding of cosmic processes is well stated in the recognition by the Elohim that the Cherubim and the "flaming sword" were positioned between the human being and "the garden" of paradise "to guard the way to the tree of life" (Gen 3,24). The connecting blood then makes its first appearance in the next chapter, Gen 4,10.

In Lect. 4 the contrast between the inner life and the outer is expressed in tensions that finally come to a climax, as we saw, in those organs of the brain called the pineal gland and the pituitary body. Everything that beats in upon us from outside, in order to stand in the closest possible contact with the circulation of the blood, strives to unite with its counterpart, with what is held back by the sympathetic nervous system. For this reason we have in the pineal gland the place where what has been brought to the blood by the brain and spinal cord unites with what approaches from the other direction; and the pituitary body is there as a last outpost to prevent the approach of what has to do with the life of the inner person. Everything that we live through in our inner organization remains below our consciousness and would be terribly disturbing if it were otherwise. It is kept back from our consciousness by the sympathetic nervous system. Only when this reciprocal relationship between the two nervous systems, as expressed in the state of tension between the pineal gland and the pituitary body, is not in order does something result that disturbs us on one side or the other. This takes place when some irregularity in the activity of our digestive organs expresses itself in our consciousness in feelings of discomfort. Or it takes place when we have a breaking through from the other direction into the organism, in special emotions such as anger and the like, which originate in our consciousness and have a particularly strong influence on us. It is thus possible for these two sides of human nature to act reciprocally upon each other, the human creature being the duality that it is.