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Can Supersensible Facts Be Proven?

by Hermann Poppelbaum, published in
Journal for Anthroposophy, Spring, 1970, #11.

Special thanks to The Journal for Anthroposophy for allowing us to reprint this article.

The remarkable success that our century has witnessed in all fields of science, theoretical and applied, has often betrayed us into optimistic dreams of progress. Recently, however, the use of the atom bomb, deadly pesticides, etc., has raised such moral questions that many of those who previously believed in an automatic improvement of culture through science have been seized by a profound scepticism and now put their hopes in a return to a pre-scientific past. Whether we share such hopes or not, we must admit that the reputation of science, even of human knowledge itself, is at stake. We have come to a crisis of confidence in scientific pursuits.

Even those who do not doubt must realize that the road forward will be blocked if human knowledge is curtailed and hemmed in as it has been in recent centuries. Unfortunately, they do not see how one could try to extend its limits without inviting disaster. Only a small minority venture to speak of an extension of knowledge beyond its traditional limits. They regard this possibility as having been opened up by Rudolf Steiner in the development of Spiritual Science or Anthroposophy and they are therefore necessarily interested in finding what justification there is for the claim of Anthroposophy to be a legitimate and safe extension of knowledge into the realm of supersensible facts. They realize, of course, that any description of alleged supersensible facts must meet the rigorous standards for knowledge that have been set up for our age. This leads at once to the problem of proof.

The mere claim that anyone has “experienced” supersensible facts cannot satisfy a conscientious seeker. Are not, he will say, hallucinations experienced, too? What guarantee is there that the so-called spiritual investigator is not under a constant illusion that has grown in him into an elaborate and coherent system? Nor can the intensity with which a supersensible impression “comes” be called upon as a support. It speaks against rather than in favor of its validity, since everybody knows that the danger with all illusions is that they are so obviously “there” — for those who have them.

Can, then, supersensible facts be proven? For the sake of fairness to the seeker this question must find a straightforward answer.


Let us first find out what is regarded as a proof in the common sense of the word. The man in the street calls proof any evidence that is brought before the bodily senses and recognized as an integral part of the thing to be proven, as a broken safe and its missing contents are “proof” of an act of burglary. It is usually not realized, however, that the evidence itself can only be assessed by thinking. A broken safe found in the morning in an office is not seen as evidence of burglary with the eyes of the body but only as a result of piecing together a whole situation. Even in common things the conclusiveness of a proof appears only to one who is ready to do some thinking.

It is similar with scientific proofs. They never lie in an object or process perceived, but in the context in which the object or process has its place. This must by no means be overlooked.

A long road must be traversed before an experimental contrivance for a proof in natural science can be built and put to use. After the apparatus is set up, we tend to overlook the fact that its parts reflect the thought-operations that have led to its construction. Yet only thinking can tell us how far such an apparatus can serve for producing evidence. Take the following example.

A twisted tapering tube of newspaper, with a short piece of glass tubing tied to it at the narrow end, is inserted obliquely into the clamp of a laboratory stand. For those who know a little chemistry, it is reasonable to say that this modest apparatus duplicates the essentials of a gas factory. Ignite the lower end of the paper tube, and the rising vapors escape from the glass tube above, where they can be kindled. It all seems very clear for those who understand it. But mere looking at the apparatus does not tell us that this is a gas factory on a small and simplified scale. It certainly looks totally unlike a factory. Only an analysis of the conditions obtaining in both can reveal what they have in common and why the one is a duplication of the other in spite of the lack of any resemblance. The apparatus can “prove” that the dry distillation of wood-substance produces combustible gas, but no simpleton can ever see it. Thinking is required.

Take an example from modern chemistry. The investigations of Henry Moseley about the kinship of chemical elements and their arrangement in an ascending scale of atomic numbers (the so-called periodic system) were carried out with an instrument enabling one to measure the defraction of cathode rays. One can hardly overlook the enormous work that had to be done, long before Moseley, to make this method possible. When the instrument is used, however, the only thing to which attention is paid is the angle at which rays are bent; various angles correspond to various elements. All the rest is inference drawn from the logic already incorporated in the setting. It is only in the context of this setting that the reading of a given angle of defraction makes sense and allows one to arrive at far-reaching conclusions. No person who has not understood the complicated thoughts embodied in the visible set-up and its applications can have any idea of how the conclusions are arrived at, and he remains literally unable to subscribe to these conclusions. By no art of persuasion can he be convinced. The conclusions are for him just so many words, and the whole enterprise may even appear to him as a fake.

There is no such thing as “sensory evidence” for scientific truth. The proof never becomes visible to outer eyes. It remains an operation in the sanctum of the scientific mind.

To take an example from modern biology, let us consider how Mendel's law of segregation is arrived at. True, there are visible objects involved in the experiment, namely the individual plants with their different characteristics such as red or white flowers. The procedure consists in counting the individuals that bear one of the two traits through several generations produced by crossbreeding. The results are expressed as percentages of the progeny. A number of assumptions have to be made as part of the argument. The outcome of the experiments is recorded through several seasons. The conclusions are drawn from the interpretation of the records. Thus they are “proven.” Everybody who can follow the argument can also see how far the proof is conclusive. This is frankly admitted, but the reverse is often overlooked: namely, that nobody who does not see the argument through to its end can possibly regard the proof as actually established.

The obviousness of the proof, to say it once more, is to be found in the connecting thought-operations, which must not contain any gap or jump and must be invulnerable to various lurking fallacies. Otherwise the proof does not “stand” criticism. It must lead also to further inferences to be tested by similar mental operations. In short, the findings, although they can and must be cross-checked, are found by thinking and not by sense-observation.

This does not in the least belittle the validity of scientific proofs. On the contrary it points out the region in which their conclusiveness must necessarily be sought. For in popular ideas about science the region of confirmation is very often clouded, and semi-scientific, so-called popular presentations are often especially guilty of vagueness in this respect. They have nourished the common fallacy that sense-evidence “underlies” statements of science.

In passing from the accepted sciences to the science of supersensible findings, it will be well to keep in mind the character of the evidence that is justly considered as proof. The claim of this science of supersensible facts (Anthroposophy) is that it makes spiritual facts available in the same sense that the accepted sciences make their facts available. We can easily see that, whatever the content of supersensible observations may be, conclusions can be based upon them only if they are checked by the logical thought-operations that connect one observation with the other. We must pass from one observation to the next by thinking, just as we do in common science. The evidence is contained in the obviousness of the transitions we make as — while the process of linking-up goes on — a wealth of observations (supersensible perceptions) is brought into a closely-knit web of logical links. Be it understood, however, that logic alone could never bring about the perceptions; there must be no speculation, no mere guessing. The perceptions stand on their own feet just as sensible perceptions do.

Observations, for instance, of the experience that the soul goes through in sleep may stand before the seeker just as abruptly and challengingly to begin with as do the outer characteristics of a chemical process. They demand to be understood just as well as the latter. Unless they are penetrated by thinking they do not yet tell their story, just as little as do disconnected observations concerning the melting point and boiling point of a substance. It is left to our thinking to find the concept that connects them and to seek the relationship to other facts independently observed. Thus, it appears to spiritual research that the “sleep experience” consists in a review of the deeds and omissions of the previous day, and further that this review anticipates an experience of the soul after death. The latter experience must, however, first be independently found before it can be tied up with the sleeping experience, which was observed by itself without as yet casting about for resemblances. The resemblance, its quality and degree, and also the differences, appear to the thinker only after surveying his observational results. Just like an ordinary thinking observer, the spiritual investigator has to find how far this resemblance goes. He is “struck” by the resemblance, no matter whether he or another person has made the observation. This is why Rudolf Steiner stressed that a supersensible investigator, besides using his clairvoyant faculties, must always have his own thinking self as a judge of truth beside him. Only as a thinker can he ascertain how far his various observations make sense.

He can not accept any supersensible observation on its face value. He must try to make this observation repeatedly, under varying circumstances, from different starting points. He must “cross-check” it with others in order to validate it. The beginner in the study of such facts, attracted by their novelty and surprising character, may care little what trouble it took the first discoverer to make them safe against fallacies, which beset this way of research no less than they endanger ordinary scientific results. But in progressing with his study, the pupil will grow conscious of the infinite care that had to be taken before the results were brought before him as definite statements. His own thought is challenged just as was the judgement of the original discoverer. He needs no belief because his own thinking is called upon. [Footnote here: Compare the article on “The Will to Believe and the Duty to Know” in the author's Man's Eternal Biography — Adonis Press. New York.]

The following-up of supersensible data recorded and presented in the context given in anthroposophic publications requires the thinking cooperation of the student. He is not only allowed, but factually required, to see whether the describer “talks sense.” What he could never do were he faced with an isolated observation, he can and even must do when he examines the context of the multiple data arrayed before him. He must get an independent and genuine impression of how they support one another.

This does not mean that he will find no contradictions among the facts recorded. If it were so, if he found them merely agreeing with one another, he would have cause for suspicion. Every student of philosophy knows that the most unsound systems have boasted of their inner coherence. It was the error of Rationalism that mere coherence was taken to be proof of the validity of a thought-out system. The crystal clarity of a rationalistic thought-web is no proof of its real value, but only of the cleverness of him who has woven it.

Anthroposophical facts, on the contrary, may often appear to contradict each other when first found. They are not made up from “principles” but independently observed, and thus it remains to be seen how they can tie up. It is with them as it is with observations of the same object in physical space from various angles. Rudolf Steiner often warns his readers of apparent inconsistencies, which at first sight shock them and raise doubts as to whether two statements are both true. Entering into the statements more carefully, the student, can find them to be supplementary just as are two photographs of the same tree taken from opposite directions. And just as two photographs, when compared and attributed to their respective points of direction, give a fuller picture than one, so two anthroposophic descriptions, by means of their seemingly contradictory nature, evoke in the student a fuller impression of supersensible reality as soon as he “puts them together.” Complete descriptions are “all-around” descriptions in the supersensible as in the sensible field.

Having thus gained an insight into the role of thinking in the coordination of supersensible facts, the student may feel ready to take another step, namely to realize that in supersensible research the polarity of observation and thinking is modified in a peculiar way. Their contrast is not as sharp as we might theoretically expect. When describing the way in which the perceptual organs for spirit-observations grow and mature, Rudolf Steiner found himself compelled to say that it is from the faculty of thinking that they draw their powers. The first state of supersensible vision at least may be called a transformed thought activity. Thinking, which in ordinary conditions is only applied to observations made by the senses, becomes, as it develops, an organ of sight quite by itself. Ordinary thinking is used to link and separate sensible observations; abstract thinking grasps their relationships, and even links up several relationships with each other. As the independent (body-free) ability of thinking further matures (through exercises designed for the purpose [Footnote here: Knowledge of the Higher Worlds and its Attainment. Rudolf Steiner. Anthroposophic Press, New York.]) it becomes of itself able to behold facts of a supersensible nature. The sound judgement must nevertheless, as we mentioned before, remain unimpaired and therefore able to manipulate and coordinate the facts that the transformed thinking begins to supply. In this sense, observation and thinking still remain as two separate faculties applied in closest cooperation. Thinking itself, on the way to higher development, provides the light that makes facts visible as it is directed on them. The seer, after perception, does with the object grasped just as does the thinker with a sense-object: he judges it and places it into a reasonable context.

In this context, the supersensible facts can be made understandable to anyone who is interested in them. He needs no seership to make them his own. He can make them his convictions and, within reasonable limits, expound them to others just as every student can with facts of the usual scientific order.

In this ability to “convey” spiritual facts to the listener or reader in such a manner that he can convince himself of their reasonability lies the difference between a mere clairvoyant and spiritual investigator. It is evident that only the latter has an orderly scientific method that lays his findings open to later corroboration, correction, or replacement by better ones. The mere clairvoyant must demand belief because he cannot convince.


There is, however, also an indirect way in which spiritual findings can be put to the test. This is especially the case where they bear upon a field in which there are also findings gained by the standard methods of natural science. Rudolf Steiner provided innumerable opportunities for verification by deliberately bringing his results to such concreteness that they come within reach of current experimental procedures. He welcomed such a critical approach as wholesome, for it is a step beyond barren theoretical scepticism. It is clear that theoretical objections vanish as soon as the practical experiment has positive results. In this case the tables are turned; the one who undertakes to experiment scientifically with spiritual data and finds that they “work” is at once himself tested for his readiness to give up previous opposition. This kind of testing cuts both ways.

The scientific, medical and agricultural lectures of Rudolf Steiner teem with concrete data, that may so challenge a conscientious investigator that he will want to test their possibilities. Not always does he need complicated apparatus; in some cases he can go to work as soon as he can get the objects together in a suitable arrangement. Let us take an example from the field of agriculture and gardening. The suggestions of Rudolf Steiner concerning improved and refined fertilizing methods (summarized now under the name of “Biodynamics”) have earned a good reputation since they were first made in 1924. A number of preparations of extremely high dilution can be manufactured from certain common plants, which were studied by Rudolf Steiner by means of spiritual scientific methods. He indicated which of them, when sprayed on the soil or on certain fodder plants, would further the growth of roots or improve the foliage or seeds. He made his statements without himself trying them out, but right from the first these sprays proved singularly effective. The predicted effects appeared and could be established beyond doubt by careful comparison with untreated plants under identical conditions, and by weighing and analysing the ashes. The plants had undergone definite changes under the impact of the sprays in spite of the minute amounts applied. The procedures that produced the sprays were devised entirely out of direct spiritual insight into the plants' formative secrets. No speculation could ever have yielded suggestions of such concreteness, nor could any person unfamiliar with the spiritual aspects of plant-chemistry have anticipated that such odd and novel methods would produce any results at all.

The tests were made on a small scale and then on larger plots, with all the necessary precautions; they were counter-tested in control-experiments and repeated under varied conditions; in short, they were conducted in the same way as any scientists would test a “working hypothesis.” The results bore out the expectations and yielded a wealth of findings not contained in the original suggestion. So the testing experiments did not only prove what the spiritual investigator had said about the forces working in plant and soil, but added useful knowledge about dosage, time of application, influence of climate, and the like. A substantial contribution was thus made to the practical handling of soil and plants.

We remind the reader that this was only one example chosen to show how spiritual-scientific data, besides being dealt with in their own proper sphere, can also be put to test where their consequences extend into the sphere of accepted experimental methods. This is what we called above the indirect proof of the validity of data that have been gained in a way that often meets with stubborn scepticism today. The broadening experience of courageous practical workers must gradually wear down the resistance of habitual prejudice; and it has already gone a long way towards doing this.

The fact that a whole school of medical knowledge and practice developed from the lectures of Rudolf Steiner to physicians [Footnote here: Rudolf Steiner, Spiritual Science and Medicine. Twenty Lectures to Doctors, 1920: Geisteswissenschaftliche Gesichtspunkte zur Therapie (Anthroposophical Spiritual Science and Medical Therapy), Nine Lectures, 1921: Anthroposophical Approach to Medicine, 1922.] is another example of how spiritual facts can be put to a practical test. Such testing, needless to say, is independent of the physician's knowledge, or even approval, of the way in which the original spiritual discoveries were made. If, for instance, he finds a description of a relationship between processes in the kidney system and in the brain (as can be found in one of the lectures), he can set to work with it as a hypothesis. The image of the counterpart-character of both processes is in his mind, but the physiological details pointing toward it are found independently of this image. As he finds ever more single facts and adds to these still others as he proceeds to therapeutic measures in accordance with them, his own picture of the polarity in question grows richer. By and by he can say that he now has a sensible-supersensible picture of a basic spiritual fact. The same will happen with other facts, all of which can thus be “substantiated” and are no longer to be called hypothetical. Gradually, through a deliberate empirical attitude, the status of these facts is so altered that they make part of the physician's knowledge. They are now really his own. This is a striking example of how Anthroposophy brings about a transformation of our rigid traditional conceptions. Even the concept of a proof is affected. It is no longer a merely logical operation applied to perceptions in a neutral fashion. The proof is no longer super-added to the facts, but it is already implicit in the way by which the facts are sought. [Footnote here: Rudolf Steiner, Occult Science, an Outline.] The old type of super added proof can still be applied to propositions in the inorganic realm. The new type of proof is suited to all problems of an organic nature.

A proof of this kind does not lose in conclusiveness. It is in fact the only way to do justice to living interrelations such as are studied in biology, physiology, and psychology and handled practically in agriculture and medicine.

Let there be no misunderstanding. We have not given here an introduction to a spiritual-scientific medicine and agriculture. The reader will have to find his own way into both fields if he is interested in them. We have only taken our examples from these fields, examples intended to show what kind of proof can be called adequate in them. We realize that by sheer force of habit the demands for the “super-added proofs” to spiritual-scientific statements will continue to be raised. Nevertheless it is time to show that it is mere habit and not the innate necessity of the subjects which raises these demands.

It must also be understood that the step from the “super-added proof” to the “proof embodied in the search for facts” is not a retreat from a rigorous standard of testing to something less demanding. It would be most unfortunate if we felt we had to apologize for not living up to accepted standards. We are not failing to comply with a justified demand, but are asserting that the new type of proof here described is the one that does justice to the peculiar field for which it is designed. The step does not yield ground, but proceeds from a questionable adequacy to a more obvious one. The proving procedure, to repeat it once more, is transferred from outside to within, since it works already in the search for facts. It operates in conjunction with the perceptual activity. In the accepted sciences, thinking must control research or else the findings may be wrong; in supersensible science thinking must become itself an organ of search or else nothing valuable will be discovered at all. But anything that is discovered in this way bears clues indicating to which other facts it belongs. Indeed, facts of the supersensible order need not be tied artificially to others but join them quite spontaneously like letters magically arranging themselves to form words. The phenomena, by their natural relationships, begin to express themselves as to the underlying more general fact (law) almost without the interference of the seeker, who merely observes how they strive towards each other. He attends, as it were, a meeting of the single phenomena; they communicate their law to him. And he can put this into human language. It was this that Goethe experienced many times and that enabled him to find the famous formula: “Do not see anything hidden behind the phenomena; they in themselves are the theory.” One could, with little change, adapt this sentence so that it expresses the new form of spiritual validation: “Do not add any proof to the phenomena from outside; your path of search for their context contains in itself the proof.”


It remains to be said that the most comprehensive testing of spiritual truth lies in its insertion into the course of actual human life. To carry a spiritual truth with us and to find how it progressively validates itself in experience is the most realistic corroboration. “Truth is what works” — this sentence must not be understood in a short-sighted manner, as if it meant that each contention is true that produces cheap success or gives a merely personal satisfaction. Nothing can be farther than such narrow pragmatism from the self-validation that is a gradual and even painful process for which the human soul is the state of action. Not the subjective approval of a statement is here the point, because this would only lead to self-satisfaction; and such self-satisfaction is only a “shabby indulgence”, as Nietzsche said. Man loses his dignity by thus trivialising his standard. “The proof of the pudding is in the eating” — this may hold good on the pudding-level, but Truth requires another measure than that of “feeling good” after accepting a part of it. We cannot judge it by whether or not it “agrees” with us. [Footnote here: “The Will to Believe and the Duty to Know” in the author's Man's Eternal Biography.]

A final possibility for verifying a spiritual-scientific description is one that must be left entirely to the free decision of the seeker. It is the possibility of traveling the path of supersensible knowledge. We have shown above that the student has a number of other criteria from which to judge. So the contention, often made, that he who wants to convince himself of spirit-facts must become a spiritual investigator himself, is obviously at variance with the true situation. Indeed, if every seeker had to become an investigator, we would not need a spiritual science at all. For, just as in ordinary science, the benefit of its existence is for the many, while the original work of discovery has to be carried out by a minority.

But for those who want to try for themselves, detailed advice as to how to proceed is given in spiritual-scientific writings and lectures. In fact, each of the major works of Rudolf Steiner contains a chapter on the “Path of Knowledge.” Furthermore, the ‘School for Spiritual Science’ in Dornach, Switzerland, provides an objective course of training under conditions similar to those used in current science for the purpose of avoiding amateurish dabbling. We need not here point out the stages of education for such spiritual-scientific research because these are described sufficiently in anthroposophic literature. [Footnote here: Particularly in Theosophy, Occult Science, an Outline, and Knowledge of the Higher Worlds and its Attainment.] What matters here is that the mere examination of the methods — without using them — leads to an insight into their reasonability. And thus again Anthroposophy has something in common with the accepted practice of ordinary science, namely that the publicity of the methods used permits the critic to see “how it is done”, even if he is not ready or able to “do it” himself. Everybody who studies science can see how a telescope or a microscope is built and used, and thus without doing any research work himself he can gain a justified confidence in the reasonableness of using such instruments. What would become of astronomy if every student wanted, or was expected, to postpone the learning until he could do research work himself? And would not all the labors of astronomers throughout the centuries have been in vain if every one had to begin at the beginning? It is no different with the spiritual facts presented by Anthroposophy. They are there to work with, no matter whether the student ever reaches the point where he can add to them.

That he does not require belief has been pointed out above. And the safeguard will always be present if he is ready to put his thinking into operation and allows his intelligent experience to broaden and deepen. Anthroposophical truths appeal to a healthy unprejudiced judgment. They have nothing to fear from such a court of appeal. They are handed to mankind in full confidence, which is the basis of Rudolf Steiner's memorable words: “Let people scrutinize what we do and test what we say. The more carefully they examine, the more confident shall we feel.”

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