The Light Course
2 January 1920, Stuttgart
My dear Friends,
I am sorry these explanations have had to be so improvised and brief, so that they scarcely go beyond mere aphorisms. It is inevitable. All I can do during these days is to give you a few points of view, with the intention of continuing when I am here again, so that in time these explanations may be rounded off, to give you something more complete. Tomorrow I will give a few concluding aspects, also enabling us to throw some light on the educational use of scientific knowledge. Now to prepare for tomorrow, I must today draw your attention to the development of electrical discoveries, beginning no doubt with things that are well-known to you from your school days. This will enable us, in tomorrow's lecture, to gain a more comprehensive view of Physics as a whole.
You know the elementary phenomena of electricity. A rod of glass, or it may be of resin, is made to develop a certain force by rubbing it with some material. The rod becomes, as we say, electrified; it will attract small bodies such as bits of paper. You know too what emerged from a more detailed observation of these phenomena. The forces proceeding from the glass rod, and from the rod of resin or sealing-wax, prove to be diverse. We can rub either rod, so that it gets electrified and will attract bits of paper. If the electrical permeation, brought about with the use of the glass rod, is of one kind, with the resinous rod it proves to be opposite in kind. Using the qualitative descriptions which these phenomena suggest, one speaks of vitreous and resinous electricities respectively; speaking more generally one calls them “positive” and “negative”. The vitreous is then the positive, the resinous the negative.
Now the peculiar thing is that positive electricity always induces and brings negative toward itself in some way. You know the phenomenon from the so-called Leyden Jar. This is a vessel with an electrifiable coating on the outside. Then comes an insulating layer (the substance of the vessel). Inside, there is another coating, connected with a metal rod, ending perhaps in a metallic knob (Figure IXa). If you electrify a metal rod and impart the electricity to the one coating, so that this coating will then evince the characteristic phenomena, say, of positive electricity, the other coating thereby becomes electrified negatively. Then, as you know, you can connect the one coating, imbued with positive, and the other, imbued with negative electricity, so as to bring about a connection of the electrical forces, positive and negative, with one another. You have to make connection so that the one electricity can be conducted out here, where it confronts the other. They confront each other with a certain tension, which they seek to balance out. A spark leaps across from the one to the other. We see how the electrical forces, when thus confronting one another, are in a certain tension, striving to resolve it. No doubt you have often witnessed the experiment.
Here is the Leyden Jar, — but we shall also need a two-pronged conductor to discharge it with. I will now charge it. The charge is not yet strong enough. You see the leaves repelling one another just a little. If we charged this sufficiently, the positive electricity would so induce the negative that if we brought them near enough together with a metallic discharger we should cause a spark to fly across the gap. Now you are also aware that this kind of electrification is called frictional electricity, since the force, whatever it may be, is brought about by friction. And — here again, I am presumably still recalling what you already know — it was only at the turn of the 18th and 19th centuries that they discovered, in addition to this “frictional electricity”, what is called “contact electricity”, thus opening up to modern Physics a domain which has become notably fruitful in the materialistic evolution of this science.
I need only remind you of the main principles. Galvani observed the leg of a frog which was in touch with metal plates and began twitching. He had discovered something of very great significance. He had found two things at once, truth to tell, — two things that should really be distinguished from one-another and are not yet quite properly distinguished, unhappily for Science, to this day. Galvani had discovered what Volta, a little later, was able to describe simply as “contact electricity”, namely the fact that when diverse metals are in contact, and their contact is also mediated by the proper liquids, an interaction arises — an interaction which can find expression in the form of an electric current from the one metal to the other. We have then the electric current, taking place to all appearances purely within the inorganic realm. But we have something else as well, if once again we turn attention to the discovery made by Galvani. We have what may in some sense be described as “physiological electricity”. It is a force of tension which is really always there between muscle and nerve and which can be awakened when electric currents are passed through them. So that in fact, that which Galvani had observed contained two things. One of them can be reproduced by purely inorganic methods, making electric currents by means of different metals with the help of liquids. The other thing which he observed is there in every organism and appears prominently in the electric fishes and certain other creatures. It is a state of tension between muscle and nerve, which, when it finds release, becomes to all appearances very like flowing electricity and its effects. It was then these discoveries which led upon the one hand to the great triumphs in materialistic science, and on the other hand provided the foundations for the immense and epoch-making technical developments which followed.
Now the fact is, the 19th century was chiefly filled with the idea that we must somehow find a single, abstract, unitary principle at the foundation of all the so-called “forces of Nature”. It was in this direction, as I said before that they interpreted what Julius Robert Mayer, the brilliant Heilbronn doctor had discovered. You will remember how we demonstrated it the other day. By mechanical force we turned a flywheel; this was attached to an apparatus whereby a mass of water was brought into inner mechanical activity. The water thereby became warmer, as we were able to shew. The effect produced — the development of warmth — may truly be attributed to the mechanical work that was done. All this was so developed and interpreted in course of time that they applied it to the most manifold phenomena of Nature, — nor was it difficult to do so within certain limits. One could release chemical forces and see how warmth arose in the process. Again, reversing the experiment which we have just described, warmth could be used in such a way as to evoke mechanical work, — as in the steam-engine and in a multitude of variations.
It was especially this so-called transformation of Nature's forces on which they riveted attention. They were encouraged to do this by what began in Julius Robert Mayer's work and then developed ever further. For it proves possible to calculate, down to the actual figures, how much warmth is needed to produce a given, measurable amount of work; and vice-versa, how much mechanical work is needed to produce a given, measurable amount of warmth or heat. So doing, they imagined — though to begin with surely there is no cause to think of it in this way — that the mechanical work, which we expended for example in making these vanes rotate in the water, has actually been transformed into the warmth. Again, they assumed that when warmth is applied in the steam-engine, this warmth is actually transformed into the mechanical work that emerges. The meditations of physicists during the 19th century kept taking this direction: they were always looking for the kinship between the diverse forces of Nature so-called, — trying to discover kinships which were to prove at last that some abstract, everywhere equal principle is at the bottom of them all, diverse and manifold as they appear. These tendencies were crowned to some extent when near the end of the century Heinrich Hertz, a physicist of some genius, discovered the so-called electric waves — here once again it was waves! It certainly seemed to justify the idea that the electricity that spreads through space is in some way akin to the light that spreads through space, — the latter too being already conceived at that time as a wave-movement in the ether.
That “electricity” — notably in the form of current electricity — cannot be grasped so simply with the help of primitive mechanical ideas, but makes it necessary to give our Physics a somewhat wider and more qualitative aspect, — this might already have been gathered from the existence of induction currents as they are called. Only to indicate it roughly: the flow of an electric current along a wire will cause a current to arise in a neighbouring wire, by the mere proximity of the one wire to the other. Electricity is thus able to take effect across space, — so we may somehow express it. Now Hertz made this very interesting discovery:— he found that the electrical influences or agencies do in fact spread out in space in a way quite akin to the spreading of waves, or to what could be imagined as such. He found for instance that if you generate an electric spark, much in the way we should be doing here, developing the necessary tension, you can produce the following result. Suppose we had a spark jumping across this gap. Then at some other point in space we could put two such “inductors”, as we may call them, opposite and at a suitable distance from one-another, and a spark would jump across here too.
This, after all, is a phenomenon not unlike what you would have if here for instance — Figure IXb — were a source of light and here a mirror. A cylinder of light is reflected, this is then gathered up again by a second mirror, and an image arises here. We may then say, the light spreads out in space and takes effect at a distance. In like manner. Hertz could now say that electricity spreads out and the effect of it is perceptible at a distance. Thus in his own conception and that of other scientists he had achieved pretty fair proof that with electricity something like a wave-movement is spreading out through space, — analogous to the way one generally imagines wave-movements to spread out. Even as light spreads out through space and takes effect at a distance, unfolding as it were, becoming manifest where it encounters other bodies, so too can the electric waves spread out, becoming manifest — taking effect once more — at a distance. You know how wireless telegraphy is based on this.
The favourite idea of 19th century physicists was once again fulfilled to some extent. For sound and light, they were imagining wave-trains, sequences of waves. Also for warmth as it spreads outward into space, they had begun to imagine wave-movements, since the phenomena of warmth are in fact similar in some respects. Now they could think the same of electricity; the waves had only to be imagined long by comparison. It seemed like incontrovertible proof that the way of thinking of 19th century Physics had been right.
Nevertheless, Hertz's experiments proved to be more like a closing chapter of the old. What happens in any sphere of life, can only properly be judged within that sphere. We have been undergoing social revolutions. They seem like great and shattering events in social life since we are looking rather intently in their direction. Look then at what has happened in Physics during the 1890's and the first fifteen years, say, of our century; you must admit that a revolution has here been going on, far greater in its domain than the external revolution in the social realm. It is no more nor less than that in Physics the old concepts are undergoing complete dissolution; only the physicists are still reluctant to admit it. Hertz's discoveries were still the twilight of the old, tending as they did to establish the old wave-theories even more firmly. What afterwards ensued, and was to some extent already on the way in his time, was to be revolutionary.
I refer now to those experiments where an electric current, which you can generate of course and lead to where you want it, is conducted through a glass tube from which the air has to a certain extent been pumped out, evacuated. The electric current, therefore, is made to pass through air of very high dilution. High tension is engendered in the tubes which you here see. In effect, the terminals from which the electricity will discharge into the tube are put far apart — as far as the length of the tube will allow. There is a pointed terminal at either end, one where the positive electricity will discharge (i.e. the positive pole) at the one end, so too the negative at the other. Between these points the electricity discharges; the coloured line which you are seeing is the path taken by the electricity. Thus we may say: What otherwise goes through the wires, appears in the form in which you see it here when it goes through the highly attenuated air. It becomes even more intense when the vacuum is higher. Look how a kind of movement is taking place from the one side and the other, — how the phenomenon gets modified. The electricity which otherwise flows through the wire: along a portion of its path we have been able, as it were, so to treat it that in its interplay with other factors it does at last reveal, to some extent, its inner essence. It shews itself, such as it is; it can no longer hide in the wire! Observe the green light on the glass; that is fluorescent light. I am sorry I cannot go into these phenomena in greater detail, but I should not get where I want to in this course if I did not go through them thus quickly. You see what is there going through the tube, — you see it in a highly dispersed condition in the highly attenuated air inside the tube.
Now the phenomena which thus appeared in tubes containing highly attenuated air or gas, called for more detailed study, in which many scientists engaged, — and among these was Crookes. Further experiments had to be made on the phenomena in these evacuated tubes, to get to know their conditions and reactions. Certain experiments, due among others to Crookes, bore witness to a very interesting fact. Now that they had at last exposed it — if I may so express myself — the inner character of electricity, which here revealed itself, proved to be very different from what they thought of light for instance being propagated in the form of wave-movements through the ether. What here revealed itself was clearly not propagated in that way. Whatever it is that is shooting through these tubes is in fact endowed with remarkable properties, strangely reminiscent of the properties of downright matter. Suppose you have a magnet or electromagnet. (I must again presume your knowledge of these things; I cannot go into them all from the beginning.) You can attract material objects with the magnet. Now the body of light that is going through this tube — this modified form, therefore, of electricity — has the same property. It too can be attracted by the electromagnet. Thus it behaves, in relation to a magnet, just as matter would behave. The magnetic field will modify what is here shooting through the tube.
Experiments of this kind led Crookes and others to the idea that what is there in the tube is not to be described as a wave-movement, propagated after the manner of the old wave-theories. Instead, they now imagined material particles to be shooting through the space inside the tube; these, as material particles, are then attracted by the magnetic force. Crookes therefore called that which is shot across there from pole to pole, (or howsoever we may describe it; something is there, demanding our consideration),— Crookes called it “radiant matter”. As a result of the extreme attenuation, he imagined, the matter that is left inside the tube has reached a state no longer merely gaseous but beyond the gaseous condition. He thinks of it as radiant matter — matter, the several particles of which are raying through space like the minutest specks of dust or spray, the single particles of which, when charged electrically, will shoot through space in this way. These particles themselves are then attracted by the electromagnetic force. Such was his line of thought: the very fact that they can thus be attracted shews that we have before us a last attenuated remnant of real matter, not a mere movement like the old-fashioned ether-movements.
It was the radiations (or what appeared as such) from the negative electric pole, known as the cathode, which lent themselves especially to these experiments. They called them “cathode rays”. Herewith the first breach had, so to speak, been made in the old physical conceptions. The process in these Hittorf tubes (Hittorf had been the first to make them, then came Geissler) was evidently due to something of a material kind — though in a very finely-divided condition — shooting through space. Not that they thereby knew what it was; in any case they did not pretend to know what so-called “matter” is. But the phenomena indicated that this was something somehow identifiable with matter, — of a material nature.
Crookes therefore was convinced that this was a kind of material spray, showering through space. The old wave-theory was shaken. However, fresh experiments now came to light, which in their turn seemed inconsistent with Crookes's theory. Lenard in 1893 succeeded in diverting the so-called rays that issue from this pole and carrying them outward. He inserted a thin wall of aluminium and led the rays out through this. The question arose: can material particles go through a material wall without more ado? So then the question had to be raised all over again:
Is it really material particles showering through space, — or is it something quite different after all? In course of time the physicists began to realize that it was neither the one nor the other: neither of the old conceptions — that of ether-waves, or that of matter — would suffice us here. The Hittorf tubes were enabling them, as it were, to pursue the electricity itself along its hidden paths. They had naturally hoped to find waves, but they found none. So they consoled themselves with the idea that it was matter shooting through space. This too now proved untenable.
At last they came to the conclusion which was in fact emerging from many and varied experiments, only a few characteristic examples of which I have been able to pick out. In effect, they said: It isn't waves, nor is it simply a fine spray of matter. It is flowing electricity itself; electricity as such is on the move. Electricity itself is flowing along here, but in its movement and in relation to other things — say, to a magnet — it shews some properties like those of matter. Shoot a material cannonball through the air and let it pass a magnet, — it will naturally be diverted So too is electricity. This is in favour of its being of a material nature. On the other hand, in going through a plate of aluminium without more ado, it shews that it isn't just matter. Matter would surely make a hole in going through other matter. So then they said: This is a stream of electricity as such. And now this flowing electricity shewed very strange phenomena. A clear direction was indeed laid out for further study, but in pursuing this direction they had the strangest experiences. Presently they found that streams were also going out from the other pole, — coming to meet the cathode rays. The other pole is called the anode; from it they now obtained the rays known as “canal rays”. In such a tube, they now imagined there to be two different kinds of ray, going in opposite directions.
One of the most interesting things was discovered in the 1890's by Roentgen ... From the cathode rays he produced a modified form of rays, now known as Roentgen rays or X-rays. They have the effect of electrifying certain bodies, and also shew characteristic reactions with magnetic and electric forces. Other discoveries followed. You know the Roentgen rays have the property of going through bodies without producing a perceptible disturbance; they go through flesh and bone in different ways and have thus proved of great importance to Anatomy and Physiology.
Now a phenomenon arose, making it necessary to think still further. The cathode rays or their modifications, when they impinge on glass or other bodies, call forth a kind of fluorescence; the materials become luminous under their influence. Evidently, said the scientists, the rays must here be undergoing further modification. So they were dealing already with many different kinds of rays. Those that first issued directly from the negative pole, proved to be modifiable by a number of other factors. They now looked round for bodies that should call forth such modifications in a very high degree — bodies that should especially transform the rays into some other form, e.g. into fluorescent rays. In pursuit of these researches it was presently discovered that there are bodies — uranium salts for example — which do not have to be irradiated at all, but under certain conditions will emit rays in their turn, quite of their own accord. It is their own inherent property to emit such rays. Prominent among these bodies were the kind that contain radium, as it is called.
Very strange properties these bodies have. They ray-out certain lines of force — so to describe it — which can be dealt with in a remarkable way. Say that we have a radium-containing body here, in a little vessel made of lead; we can examine the radiation with a magnet. We then find one part of the radiation separating off, being deflected pretty strongly in this direction by the magnet, so that it takes this form (Figure IXc). Another part stays unmoved, going straight on in this direction, while yet another is deflected in the opposite direction. The radiation, then, contains three elements. They no longer had names enough for all the different kinds! They therefore called the rays that will here be deflected towards the right, ß-rays; those that go straight on, γ-rays; and those are deflected in the opposite direction, α-rays.
Bringing a magnet near to the radiating body, studying these deflections and making certain computations, from the deflection one may now deduce the velocity of the radiation. The interesting fact emerges that the ß-rays have a velocity, say about nine-tenths the velocity of light, while the velocity of the α-rays is about one-tenth the velocity of light. We have therefore these explosions of force, if we may so describe them, which can be separated-out and analyzed and then reveal very striking differences of velocity.
Now I remind you how at the outset of these lectures we endeavoured in a purely spiritual way to understand the formula, v = s/t. We said that the real thing in space is the velocity; it is velocity which justifies us in saying that a thing is real. Here now you see what is exploding as it were, forth from the radiating body, characterized above all by the varying intensity and interplay of the velocities which it contains. Think what it signifies: in the same cylinder of force which is here raying forth, there is one element that wants to move nine times as fast as the other. One shooting force, tending to remain behind, makes itself felt as against the other that tends to go nine times as quickly. Now please pay heed a little to what the anthroposophists alone, we must suppose, have hitherto the right not to regard as sheer madness! Often and often, when speaking of the greatest activities in the Universe which we can comprehend, we had to speak of differences in velocity as the most essential thing. What is it brings about the most important things that play into the life of present time? It is the different velocities with which the normal, the Luciferic and the Ahrimanic spiritual activities work into one-another. It is that differences of velocity are there in the great spiritual streams to which the web and woof of the world is subjected. The scientific pathway which has opened out in the most recent times is compelling even Physics — though, to begin with, unconsciously — to go into differences of velocity in a way very similar to the way Spiritual Science had to do for the great all-embracing agencies of Cosmic Evolution.
Now we have not yet exhausted all that rays forth from this radium-body. The effects shew that there is also a raying-forth of the material itself. But the material thus emanated proves to be radium no longer. It presently reveals itself to be helium for instance — an altogether different substance. Thus we no longer have the conservation, — we have the metamorphosis of matter.
The phenomena to which I have been introducing you, all of them take their course in what may be described as the electrical domain. Moreover, all of them have one property in common. Their relation to ourselves is fundamentally different from that of the phenomena of sound or light for example, or even the phenomena of warmth. In light and sound and warmth we ourselves are swimming, so to speak, as was described in former lectures. The same cannot be said so simply of our relation to the electrical phenomena. We do not perceive electricity as a specific quality in the way we perceive light, for instance. Even when electricity is at last obliged to reveal itself, we perceive it by means of a phenomenon of light. This led to people's saying, what they have kept repeating: “There is no sense-organ for electricity in man.” The light has built for itself in man the eye — a sense-organ with which to see it. So has the sound, the ear. For warmth too, a kind of warmth-organ is built into man. For electricity, they say, there is nothing analogous. We perceive electricity indirectly.
We do, no doubt; but that is all that can be said of it till you go forward to the more penetrating form of Science which we are here at least inaugurating. In effect, when we expose ourselves to light, we swim in the element of light in such a way that we ourselves partake in it with our conscious life, or at least partially so. So do we in the case of warmth and in that of sound or tone. The same cannot be said of electricity. But now I ask you to remember what I have very often explained: as human beings we are in fact dual beings. That is however to put it crudely, for we are really threefold beings: beings of Thought, of Feeling and of Will. Moreover, as I have shewn again and again, it is only in our Thinking that we are really awake, whilst in our feelings we are dreaming and in our processes of will we are asleep — asleep even in the midst of waking life. We do not experience our processes of will directly. Where the essential Will is living, we are fast asleep. And now remember too, what has been pointed out during these lectures. Wherever in the formulae of Physics we write m for mass, we are in fact going beyond mere arithmetic — mere movement, space and time. We are including what is no longer purely geometrical or kinematical, and as I pointed out, this also corresponds to the transition of our consciousness into the state of sleep. We must be fully clear that this is so. Consider then this memberment of the human being; consider it with fully open mind, and you will then admit: Our experience of light, sound and warmth belongs — to a high degree at least, if not entirely — to the field which we comprise and comprehend with our sensory and thinking life. Above all is this true of the phenomena of light. An open-minded study of the human being shews that all these things are akin to our conscious faculties of soul. On the other hand, the moment we go on to the essential qualities of mass and matter, we are approaching what is akin to those forces which develop in us when we are sleeping. And we are going in precisely the same direction when we descend from the realm of light and sound and warmth into the realm of the electrical phenomena.
We have no direct experience of the phenomena of our own Will; all we are able to experience in consciousness is our thoughts about them. Likewise we have no direct experience of the electrical phenomena of Nature. We only experience what they deliver, what they send upward, to speak, into the realms of light and sound and warmth etc. For we are here crossing the same boundary as to the outer world, which we are crossing in ourselves when we descend from our thinking and idea-forming, conscious life into our life of Will. All that is light, and sound, and warmth, is then akin to our conscious life, while all that goes on in the realms of electricity and magnetism is akin — intimately akin — to our unconscious life of Will. Moreover the occurrence of physiological electricity in certain lower animals is but the symptom — becoming manifest somewhere in Nature — of a quite universal phenomenon which remains elsewhere unnoticed. Namely, wherever Will is working through the metabolism, there is working something very similar to the external phenomena of electricity and magnetism.
When in the many complicated ways — which we have only gone through in the barest outline in today's lecture — when in these complicated ways we go down into the realm of electrical phenomena, we are in fact descending into the very same realm into which we must descend whenever we come up against the simple element of mass. What are we doing then when we study electricity and magnetism? We are then studying matter, in all reality. It is into matter itself that you are descending when you study electricity and magnetism. And what an English philosopher has recently been saying is quite true — very true indeed. Formerly, he says, we tried to imagine in all kinds of ways, how electricity is based on matter. Now on the contrary we must assume, what we believe to be matter, to be in fact no more than flowing electricity. We used to think of matter as composed of atoms; now we must think of the electrons, moving through space and having properties like those we formerly attributed to matter.
In fact our scientists have taken the first step — they only do not yet admit it — towards the overcoming of matter. Moreover they have taken the first step towards the recognition of the fact that when in Nature we pass on from the phenomena of light, sound and warmth of those of electricity, we are descending — in the realm of Nature — into phenomena which are related to the former ones as is the Will in us to the life of Thought. This is the gist and conclusion of our studies for today, which I would fain impress upon your minds. After all, my main purpose in these lectures is to tell you what you will not find in the text-books. The text-book knowledge I may none the less bring forward, is only given as a foundation for the other.