TENTH AND LAST LECTURE
Stuttgart, 3rd January 1920.
I will now
bring these few improvised hours of scientific study to a
provisional conclusion. I want to give you a few guiding lines
which may help you in developing such thoughts about Nature for
yourselves, taking your start from characteristic facts which you
can always make visible by experiment. In Science today — and
this applies above all to the teacher — it is most important
to develop a right way of thinking upon the facts and phenomena
presented to us by Nature. You will remember what I was trying to
shew yesterday in this connection. I shewed how since the 1890's
physical science has so developed that materialism is being lifted
right out of its bearings, so to speak, even by Physics itself.
This is the point to remember above all in this connection.
The period
when Science thought that it had golden proofs of the universality
of waves and undulations was followed, as we say, by a new time. It
was no longer possible to hold fast to the old wave-theories. The
last three decades have in fact been revolutionary. One can imagine
nothing more revolutionary in any realm than this most recent
period has been in Physics. Impelled by the very facts that have
not emerged, Physics has suffered no less a loss than the concept
of matter itself in its old form. Out of the old ways of thinking,
as we have seen, the phenomena of light had been brought into a
very near relation to those of electricity and magnetism. Now the
phenomena produced by the passage of electricity through tubes in
which the air or gas was highly rarefied, led scientists to see in
the raying light itself something like radiating electricity. I do
not say that they were right, but this idea arose. It came about in
this way:— The electric current until then had always been
hidden as it were in wires, and one had little more to go on than
Ohm's Law. Now one was able, so to speak, to get a glimpse of the
electricity itself, for here it leaves the wire, jumps to the
distant pole, and is no longer able as it were to conceal its
content in the matter through which it passes.
The phenomena
proved complicated. As we say yesterday, manifold types of
radiation emerged. The first to be discovered were the so-called
cathode rays, issuing from the negative pole of the Hittorf tube
and making their way through the partial vacuum. In that they can
be deflected by magnetic forces, they prove akin to what we should
ordinarily feel to be material. Yet they are also evidently akin to
what we see where radiations are at work. This kinship comes out
most vividly when we catch the rays (or whatsoever it is that is
issuing from the negative electric pole) upon a screen or other
object, as we should do with light. Light throws a shadow. So do
these radiations. Yet in this very experiment we are again
establishing the near relation of these rays to the ordinary
element of matter. For you can imagine that a bombardment is taking
place from here (as we say yesterday, this is how Crookes thinks of
the cathode rays). The “bombs” do not get through the
screen which you put in the way; the space behind the screen is
protected. This can be shewn by Crookes's experiment, interposing a
screen in the way of the cathode rays.
We will here
generate the electric current; we pass it through this tube in
which the air is rarefied. It has its cathode or negative pole
here, its anode or positive pole here. Sending the electricity
through the tube, we are now getting the so-called cathode rays. We
catch them on a screen shaped like a St. Andrew's cross. We let the
cathode rays impinge on it, and on the other side you will see
something like a shadow of the St. Andrew's cross, from which you
may gather that the cross stops the rays. Observe it clearly,
please. Inside the tube is the St. Andrew's cross. The cathode rays
go along here; here they are stopped by the cross; the shadow of
the cross becomes visible upon the wall of the vessel behind it. I
will now bring the shadow which is thus made visible into the field
of a magnet. I beg you to observe it now. You will find the shadow
influenced by the magnetic field. You see then, just as I might
attract a simple bit of iron with a magnet, so too, what here
emerges like a kind of shadow behaves like external matter. It
behaves materially.
Here then we
have a type of rays which Crookes regards as “radiant
matter” — as a form of matter neither solid, liquid or
gaseous but even more attenuated, — revealing also that
electricity itself, the current of electricity, behaves like simple
matter. We have, as it were, been trying to look at the current of
flowing electricity as such, and what we see seems very like the
kind of effects we are accustomed to see in matter.
I will now
shew you, what was not possible yesterday, the rays that issue from
the other pole and that are called “canal rays”. You
can distinguish the rays from the cathode, going in this direction,
shimmering in a violet shade of colour, and the canal rays coming
to meet them, giving a greenish light. The velocity of the canal
rays is much smaller.
Finally I will
shew you the kind of rays produced by this apparatus: they are
revealed in that the glass becomes fluorescent when we send the
current through. This is the kind of rays usually made visible by
letting them fall upon a screen of barium platinocyanide. They have
the property of making the glass intensely fluorescent. Please
observe the glass. You see it shining with a very strong,
greenish-yellow, fluorescent light. The rays that shew themselves
in this way are the Roentgen rays or X-rays, mentioned
yesterday. We observe this kind too, therefore.
Now I was
telling you how in the further study of these things it appeared
that certain entities, regarded as material substances, emit
sheaves of rays — rays of three kinds, to begin with. We
distinguished them as α-, ß-, and
γ-rays (cf. the
Figure IXc). They shew distinct properties. Moreover, yet
another thing emerges from these materials, known as radium etc. It
is the chemical element itself which as it were gives itself up
completely. In sending out its radiation, it is transmuted. It
changes into helium, for example; so it becomes something quite
different from what it was before. We have to do no longer with
stable and enduring matter but with a complete metamorphosis of
phenomena.
Taking my
start from these facts, I now want to unfold a point of view which
may become for you an essential way, not only into these phenomena
but into those of Nature generally. The Physics of the 19th century
chiefly suffered from the fact that the inner activity, with which
man sought to follow up the phenomena of Nature, was not
sufficiently mobile in the human being himself. Above all, it was
not able really to enter the facts of the outer world. In the realm
of light, colours could be seen arising, but man had not enough
inner activity to receive the world of colour into his forming of
ideas, into his very thinking. Unable any longer to think the
colours, scientists replaced the colours, which they could not
think, by what they could, — namely by what was purely
geometrical and kinematical — calculable waves in an unknown
ether. This “ether” however, as you must see, proved a
tricky fellow. Whenever you are on the point of catching it, it
evades you. It will not answer the roll-call. In these experiments
for instance, revealing all these different kinds of rays, the
flowing electricity has become manifest to some extent, as a form
of phenomenon in the outer world, — but the
“ether” refuses to turn up. In fact it was not given to
the 19th-century thinking to penetrate into the phenomena. But this
is just what Physics will require from now on. We have to enter the
phenomena themselves with human thinking. Now to this end certain
ways will have to be opened up — most of all for the realm of
Physics.
You see, the
objective powers of the World, if I may put it so, — those
that come to the human being rather than from him —
have been obliging human thought to become rather more mobile
(albeit, in a certain sense, from the wrong angle). What men
regarded as most certain and secure, that they could most rely on,
was that they could explain the phenomena so beautifully by means
of arithmetic and geometry — by the arrangement of lines,
surfaces and bodily forms in space. But the phenomena in these
Hittorf tubes are compelling us to go more into the facts. Mere
calculations begin to fail us here, if we still try to apply them
in the same abstract way as in the old wave-theory.
Let me say
something of the direction from which it first began, that we were
somehow compelled to bring more movement into our geometrical and
arithmetical thinking. Geometry, you know, was a very ancient
science. The regularities and laws in line and triangle and
quadrilateral etc., — the way of thinking all these forms in
pure Geometry — was a thing handed down from ancient time.
This way of thinking was now applied to the external phenomena
presented by Nature. Meanwhile however, for the thinkers of the
19th century, the Geometry itself began to grow uncertain. It
happened in this way. Put yourselves back into your school days:
you will remember how you were taught (and our good friends, the
Waldorf teachers, will teach it too, needless to say; they cannot
but do so), — you were undoubtedly taught that the three
angles of a triangle (Figure
Xa) together make a straight angle — an angle of
180°. Of course you know this. Now then we have to give our
pupils some kind of proof, some demonstration of the fact. We do it
by drawing a parallel to the base of the triangle through the
vertex. We then say: the angle α, which we have here,
shews itself here again as α'. α and
α' are alternate angles and therefore equal. I can
transfer this angle over here, then. Likewise this angle
ß, over here; again it remains the same.
Figure Xa
The angle
γ stays where it is. If then I have γ =
γ', α = α' and ß = ß',
while α' + ß' + γ' taken together give an
angle of 180° as they obviously do, α + ß +
γ will do the same. Thus I can prove it so that you
actually see it. A clearer or more graphic proof can scarcely be
imagined.
However, what
we are taking for granted is that this upper line A'B' is truly
parallel to the lower line AB, — for this alone enables me to
carry out the proof. Now in the whole of Euclid's Geometry there is
no way of proving that two lines are really parallel, i.e. that
they only meet at an infinite distance, or do not meet at all. They
only look parallel so long as I hold fast to a space that is merely
conceived in thought. I have no guarantee that it is so in any real
space. I need only assume that the two lines meet, in reality,
short of an infinite distance; then my whole proof, that the three
angles together make 180°, breaks down. For I should then
discover: whilst in the space which I myself construct in thought
— the space of ordinary Geometry — the three angles of
a triangle add up to 180° exactly, it is no longer so when I
envisage another and perhaps more real space. The sum of the angles
will no longer be 180°, but may be larger. That is to say,
besides the ordinary geometry handed down to us from Euclid other
geometries are possible, for which the sum of the three angles of a
triangle is by no means 180°.
Nineteenth
century thinking went a long way in this direction, especially
since Lobachevsky, and from this starting-point the question could
not but arise: Are then the processes of the real world — the
world we see and examine with our senses — ever to be taken
hold of in a fully valid way with geometrical ideas derived from a
space of our own conceiving? We must admit: the space which we
conceive in thought is only thought. Nice as it is to cherish the
idea that what takes place outside us partly accords with what we
figure-out about it, there is no guarantee that it really is so.
There is no guarantee that what is going on in the outer world does
really work in such a way that we can fully grasp it with the
Euclidean Geometry which we ourselves think out. Might it not be
— the facts alone can tell — might it not be that the
processes outside are governed by quite another geometry, and it is
only we who by our own way of thinking first translate this into
Euclidean geometry and all the formulae thereof?
In a word, if
we only go by the resources of Natural Science as it is today, we
have at first no means whatever of deciding, how our own
geometrical or kinematical ideas are related to what appears to us
in outer Nature. We calculate Nature's phenomena in the realm of
Physics — we calculate and draw them in geometrical figures.
Yet, are we only drawing on the surface after all, or are we
penetrating to what is real in Nature when we do so? What is there
to tell? If people once begin to reflect deeply enough in modern
Science — above all in Physics — they will then see
that they are getting no further. They will only emerge from the
blind alley if they first take the trouble to find out what is the
origin of all our phoronomical — arithmetical, geometrical
and kinematical — ideas. What is the origin of these, up to
and including our ideas of movement purely as movement, but not
including the forces? Whence do we get these ideas? We may commonly
believe that we get them on the same basis as the ideas we gain
when we go into the outer facts of Nature and work upon them with
our reason. We see with our eyes and hear with our ears. All that
our senses thus perceive, — we work upon it with our
intellect in a more primitive way to begin with, without
calculating, or drawing it geometrically, or analyzing the forms of
movement. We have quite other categories of thought to go on when
our intellect is thus at work on the phenomena seen by the senses.
But if we now go further and begin applying to what goes on in the
outer world the ideas of “scientific” arithmetic and
algebra, geometry and kinematics, then we are doing far more
— and something radically different. For we have certainly
not gained these ideas from the outer world. We are applying ideas
which we have spun out of our own inner life. Where then do these
ideas come from? That is the cardinal question. Where do they come
from? The truth is, these ideas come not from our intelligence
— not from the intelligence which we apply when working up
the ideas derived from sense-perception. They come in fact from the
intelligent part of our Will. We make them with our Will-system
— with the volitional part of our soul.
The difference
is indeed immense between all the other ideas in which we live as
intelligent beings and on the other hand the geometrical,
arithmetical and kinematical ideas. The former we derive from our
experience with the outer world; these on the other hand —
the geometrical, the arithmetical ideas — rise up from the
unconscious part of us, from the Will-part which has its outer
organ in the metabolism. Our geometrical ideas above all spring
from this realm; they come from the unconscious in the human being.
And if you now apply these geometrical ideas (I will say
“geometrical” henceforth to represent the arithmetical
and algebraic too) to the phenomena of light or sound, then in your
process of knowledge you are connecting, what arises from within
you, with what you are perceiving from without. In doing so you
remain utterly unconscious of the origin of the geometry you use.
You unite it with the external phenomena, but you are quite
unconscious of its source. So doing, you develop theories such as
the wave-theory of light, or Newton's corpuscular theory, —
it matters not which one it is. You develop theories by uniting
what springs from the unconscious part of your being with what
presents itself to you in conscious day-waking life. Yet the two
things do not directly belong to one-another. They belong as
little, my dear Friends, as the idea-forming faculty which you
unfold when half-asleep belongs directly to the outer things which
in your dreaming, half-asleep condition you perceive. In
anthroposophical lectures I have often given instances of how the
dream is wont to symbolize. An undergraduate dreams that at the
door of the lecture-theatre he gets involved in a quarrel. The
quarrel grows in violence; at last they challenge one-another to a
duel. He goes on dreaming: the duel is arranged, they go out into
the forest, he sees himself firing the shot, — and at the
moment he wakes up. A chair has fallen over. This was the impact
which projected itself forward into the dream. The idea-forming
faculty has indeed somehow linked up with the outer phenomenon, but
in a merely symbolizing way, — in no way consistent with the
real object. So too, what in your geometrical and phoronomical
thinking you fetch up from the subconscious part of your being,
when you connect it with the phenomena of light. What you then do
has no other value for reality than what finds expression in the
dream when symbolizing an objective fact such as the fall and
impact of the chair. All this elaboration of the outer world
— optical, acoustic and even thermal to some extent (the
phenomena of warmth) — by means of geometrical, arithmetical
and kinematical thought-forms, is in point of fact a dreaming about
Nature. Cool and sober as it may seem, it is a dream — a
dreaming while awake. Moreover, until we recognize it for what it
is, we shall not know where we are in our Natural Science, so that
our Science gives us reality. What people fondly believe to be the
most exact of Sciences, is modern mankind's dream of Nature.
But it is
different when we go down from the phenomena of light and sound,
via the phenomena of warmth, into the realm we are coming into with
these rays and radiations, belonging as they do to the science of
electricity. For we then come into connection with what in outer
Nature is truly equivalent to the Will in Man. The realm of Will in
Man is equivalent to this whole realm of action of the cathode
rays, canal rays, Roentgen rays. α-, ß- and
γ-rays and so on. It is from this very realm —
which, once again, is in the human being the realm of Will, —
it is from this that there arises what we possess in our
mathematics, in our geometry, in our ideas of movement. These
therefore are the realms, in Nature and in Man, which we may truly
think of as akin to one-another. However, human thinking has in our
time not yet gone far enough, really to think its way into these
realms. Man of today can dream quite nicely, thinking out
wave-theories and the like, but he is not yet able to enter with
real mathematical perception into that realm of phenomena which is
akin to the realm of human Will, in which geometry and arithmetic
originate. For this, our arithmetical, algebraical and geometrical
thinking must in themselves become more saturated with reality. It
is along these lines that physical science should now seek to
go.
Nowadays, if
you converse with physicists who were brought up in the golden age
of the old wave-theory, you will find many of them feeling a little
uncanny about these new phenomena, in regard to which ordinary
methods of calculation seem to break down in so many places. In
recent times the physicists have had recourse to a new device.
Plain-sailing arithmetical and geometrical methods proving
inadequate, they now introduce a kind of statistical method. Taking
their start more from the outer empirical data, they have developed
numerical relations also empirical in kind. They then use the
calculus of probabilities. Along these lines it is permissible to
say: By all means let us calculate some law of Nature; it will hold
good throughout a certain series, but then there comes a point
where it no longer works.
There are
indeed many things like this in modern Physics, — very
significant moments where they lose hold of the thought, yet in the
very act of losing it get more into reality. Conceivably for
instance, starting from certain rigid ideas about the nature of a
gas or air under the influence of warmth and in relation to its
surroundings, a scientist of the past might have proved with
mathematical certainty that air could not be liquefied. Yet air was
liquefied, for at a certain point it emerged that the ideas which
did indeed embrace the prevailing laws of a whole series of facts,
ceased to hold good at the end of this series. Many examples might
be cited. Reality today — especially in Physics — often
compels the human being to admit this to himself: “You with
your thinking, with your forming of ideas, no longer fully
penetrate into reality; you must begin again from another
angle.”
We must
indeed; and to do this, my dear Friends, we must become aware of
the kinship between all that comes from the human Will —
whence come geometry and kinematics — and on the other hand
what meets us outwardly in this domain that is somehow separated
from us and only makes its presence known to us in the phenomena of
the other pole. For in effect, all that goes on in these vacuum
tubes makes itself known to us in phenomena of light, etc. Whatever
is the electricity itself, flowing through there, is imperceptible
in the last resort. Hence people say: If only we had a sixth sense
— a sense for electricity — we should perceive it too,
directly. That is of course wide of the mark. For it is only when
you rise to Intuition, which has its ground in the Will, it is only
then that you come into that region — even of the outer world
— where electricity lives and moves. Moreover when you do so
you perceive that in these latter phenomena you are in a way
confronted by the very opposite than in the phenomena of sound or
tone for instance. In sound or in musical tone, the very way man is
placed into this world of sound and tone — as I explained in
a former lecture — means that he enters into the sound or
tone with his soul and only with his soul. What he then
enters into with his body, is no more than what sucks-in the
real essence of the sound or tone. I explained this some days ago;
you will recall the analogy of the bell-jar from which the air has
been pumped out. In sound or tone I am within what is most
spiritual, while what the physicist observes (who of course cannot
observe the spiritual nor the soul) is but the outer, so-called
material concomitant, the movement of the wave. Not so in the
phenomena of the realm we are now considering, my dear Friends. For
as I enter into these, I have outside me not only the objective,
so-called material element, but also what in the case of sound and
tone is living in me — in the soul and spirit. The
essence of the sound or tone is of course there in the outer world
as well, but so am I. With these phenomena on the other hand, what
in the case of sound could only be perceived in soul, is there in
the same sphere in which — for sound — I should have no
more than the material waves. I must now perceive physically, what
in the case of sound or tone I can only perceive in the soul.
Thus in
respect of the relation of man to the external world the
perceptions of sound, and the perceptions of electrical phenomena
for instance, are at the very opposite poles. When you perceive a
sound you are dividing yourself as it were into a human duality.
You swim in the elements of wave and undulation, the real existence
of which can of course be demonstrated by quite external methods.
Yet as you do so you become aware; herein is something far more
than the mere material element. You are obliged to kindle your own
inner life — your life of soul — to apprehend the tone
itself. With your ordinary body — I draw it diagrammatically
(the oval in
Figure Xb) — you become aware of the undulations. You
draw your ether— and astral body together, so that they
occupy only a portion of your space. You then enjoy, what you are
to experience of the sound or tone as such, in the thus inwarded
and concentrated etheric-astral part of your being. It is quite
different when you as human being meet the phenomena of this other
domain, my dear Friends. In the first place there is no wave or
undulation or anything like that for you to dive into; but you now
feel impelled to expand what in the other case you concentrated
(Figure
Xc). In all directions, you drive your ether— and astral
body out beyond your normal surface; you make them bigger, and in
so doing you perceive these electrical phenomena.
Figure Xb |
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Figure Xc |
Without
including the soul and spirit of the human being, it will be quite
impossible to gain a true or realistic conception of the phenomena
of Physics. Ever-increasingly we shall be obliged to think in this
way. The phenomena of sound and tone and light are akin to the
conscious element of Thought and Ideation in ourselves, while those
of electricity and magnetism are akin to the sub-conscious element
of Will. Warmth is between the two. Even as Feeling is intermediate
between Thought and Will, so is the outer warmth in Nature
intermediate between light and sound on the one hand, electricity
and magnetism on the other. Increasingly therefore, this must
become the inner structure of our understanding of the phenomena of
Nature. It can indeed become so if we follow up all that is latent
in Goethe's Theory of Colour. We shall be studying the element of
light and tone on the one hand, and of the very opposite of these
— electricity and magnetism — on the other. As in the
spiritual realm we differentiate between the Luciferic, that is
akin to the quality of light, and the Ahrimanic, akin to
electricity and magnetism, so also must we understand the structure
of the phenomena of Nature. Between the two lies what we meet with
in the phenomena of Warmth.
I have thus
indicated a kind of pathway for this scientific realm, — a
guiding line with which I wished provisionally to sum up the little
that could be given in these few improvised hours. It had to be
arranged so quickly that we have scarcely got beyond the good
intentions we set before us. All I could give were a few hints and
indications; I hope we shall soon be able to pursue them further.
Yet, little as it is, I think what has been given may be of help to
you — and notably to the Waldorf School teachers among you
when imparting scientific notions to the children. You will of
course not go about it in a fanatical way, for in such matters it
is most essential to give the realities a chance to unfold. We must
not get our children into difficulties. But this at least we can
do: we can refrain from bringing into our teaching too many
untenable ideas — ideas derived from the belief that the
dream-picture which has been made of Nature represents actual
reality. If you yourselves are imbued with the kind of scientific
spirit with which these lectures — if we may take them as a
fair example — have been pervaded, it will assuredly be of
service to you in the whole way you speak with the children about
natural phenomena.
Methodically
too, you may derive some benefit. I am sorry it was necessary to go
through the phenomena at such breakneck speed. Yet even so, you
will have seen that there is a way of uniting what we see outwardly
in our experiments with a true method of evoking thoughts and
ideas, so that the human being does not merely stare at the
phenomena but really thinks about them. If you arrange your lessons
so as to get the children to think in connection with the
experiments — discussing the experiments with them
intelligently — you will develop a method, notably in the
Science lessons, whereby these lessons will be very fruitful for
the children who are entrusted to you.
Thus by the
practical example of this course, I think I may have contributed to
what was said in the educational lectures at the inception of the
Waldorf School. I believe therefore that in arranging these
scientific courses we shall also have done something for the good
progress of our Waldorf School, which ought really to prosper after
the good and very praiseworthy start which it has made. The School
was meant as a beginning in a real work for the evolution of our
humanity — a work that has its fount in new resources of the
Spirit. This is the feeling we must have. So much is crumbling, of
all that has developed hitherto in human evolution. Other and new
developments must come in place of what is breaking down. This
realization in our hearts and minds will give the consciousness we
need for the Waldorf School. In Physics especially it becomes
evident, how many of the prevailing ideas are in decay. More than
one thinks, this is connected with the whole misery of our time.
When people think sociologically, you quickly see where their
thinking goes astray. Admittedly, here too most people fail to see
it, but you can at least take notice of it; you know that
sociological ways of thought will find their way into the social
order of mankind. On the other hand, people fail to realize how
deeply the ideas of Physics penetrate into the life of mankind.
They do not know what havoc has in fact been wrought by the
conceptions of modern Physics, terrible as these conceptions often
are. In public lectures I have often quoted Hermann Grimm.
Admittedly, he saw the scientific ideas of his time rather as one
who looked upon them from outside. Yet he spoke not untruly when he
said, future generations would find it difficult to understand that
there was once a world so crazy as to explain the evolution of the
Earth and Solar System by the theory of Kant and Laplace. To
understand such scientific madness would not be easy for a future
age, thought Hermann Grimm. Yet in our modern conceptions of
inorganic Nature there are many features like the theory of Kant
and Laplace. And you must realize how much is yet to do for the
human beings of our time to get free of the ways of Kant and
Konigsberg and all their kindred. How much will be to do in this
respect, before they can advance to healthy, penetrating ways of
thought!
Strange things
one witnesses indeed from time to time, shewing how what is wrong
on one side joins up with what is wrong on another. What of a thing
like this? Some days ago — as one would say, by chance
— I was presented with a reprint of a lecture by a German
University professor. (He prides himself in this very lecture that
there is in him something of Kant and Konigsberg!) It was a lecture
in a Baltic University, on the relation of Physics and Technics,
held on the 1st of May 1918, — please mark the date! This
learned physicist of our time in peroration voices his ideal,
saying in effect: The War has clearly shewn that we have not yet
made the bond between Militarism and the scientific laboratory work
of our Universities nearly close enough. For human progress to go
on in the proper way, a far closer link must in future be forged
between the military authorities and what is being done at our
Universities. Questions of mobilization in future must include all
that Science can contribute, to make the mobilization still more
effective. At the beginning of the War we suffered greatly because
the link was not yet close enough — the link which we must
have in future, leading directly from the scientific places of
research into the General Staffs of our armies.
Mankind, my
dear Friends, must learn anew, and that in many fields. Once human
beings make up their minds to learn anew in such a realm as
Physics, they will be better prepared to learn anew in other fields
as well. Those physicists who go on thinking in the old way, will
never be so very far removed from the delightful coalition between
the scientific laboratories and the General Staffs. How many things
will have to alter! So may the Waldorf School be and remain a place
where the new things which mankind needs can spring to life. In the
expression of this hope, I will conclude our studies for the
moment.
End of the
Scientific Lecture-Course
given by Rudolf Steiner at Stuttgart
23rd December 1919 to 3rd January 1920.
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