Moritz Schlick

“ We must acknowledge the great magic of art, but we must not attribute it to the wrong causes. The merit of poetry does not lie in its wonderful capacity of expression, it is to be found in the great effects it produces in our souls by that which it expresses. While the ultimate purpose of science is knowledge, perfect expression of real facts the purpose of art is to evoke in us certain emotions, and expression is but a means to this end. Emotions are content (possessing, of course, a certain structure) , they are not communicated by poetry, but produced by it. ”

“ But no fact can prove or disprove the validity of logical principles, simply because they do not assert any fact, and are, therefore, compatible with any observation.
Usually our astronomical predictions are very accurately confirmed by observations, and we may justly be proud of this mastery of the human mind over nature — but we shall be speaking nonsense if we try to express our joy and our wonder by saying : "how marvellously logical is the universe! how astonishing is the corresspondence between our reasoning and the ways of nature! ”

“ In reality there is no problem that would raise any difficulties for Logic. Our answer to those sceptical doubts is simply this: If during the short process of thinking we should forget the signification of the words (perhaps without knowing it) the consequence would be that we are unable to understand the meaning of the sentence. We have no proposition at all, but just an empty series of falsity. There is a proposition only after we have understood the sentence, and if we have understood it we have understood it as a tautology and know that it is true. ”

“ In reality of course, there are no two such fields of form and content, there is no wall between them, and there is no gate. There is just the one old world which we are "enjoying" all the time; but which we know only in so far as we express its structure or order (be it for its own sake, as in pure science, or for practical or aesthetic purposes as in ordinary life) , because what we call knowing is the expression of this order. ”

“ All this confirms our statement that knowledge does not require a real intimacy between the knower and the known and that the most perfect knowledge does not consist in a union of both. On the contrary, all knowledge seems to become more and more complete the farther we move away from the object. Think of how perfect our knowledge of the nature of matter is at the present time — at least compared with former times — and how utterly remote it is from what people thought they knew about matter by intuition ! ”

“ No one can feel more strongly than I do that the greatest miracles on earth are wrought by the poet and that no revelations and values can compare with those given to us by art, and I have the greatest admiration for the expressive power of poetry, but at the same time I know that the poet cannot express anything that could not be expressed by science, and that most certainly a volume of poetry does not communicate content any more than a scientific book. ”

“ As soon as you try to say anything more, as soon as you think that there is anything more to be said, namely about the "content" of the qualities, your assertions will not become less probable or more hypothetical, but they will cease to be assertions at all, the word "quality" will simply have become meaningless, you will not be making an intelligible use of it. The reason for this lies in the fact that no series of words will actually form a proposition, will have actual meaning, unless we can indicate a way of testing its truth, at least in principle. ”

“ Content does not enter into science. Not on account of some imperfection of scientific knowledge, not on account of some weakness of our cognitive capacity, but simply on account of the nature of all knowledge : it is essentially a matter of structure ; he who is hungry for content is hungry for something that is utterly different from knowledge — that is all. Science is a logical structure common to all who are able to study it. ”

“ Intuition, identification of mind with an object is not knowledge of the object and does not help towards it, because it does not fulfil the purpose by which knowledge is defined: this purpose is to find our way among the objects, to predict their behaviour, and that is done by discovering their order, by assigning to every object its proper place within the structure of the world. Identification with a thing does not help us to find its order, but prevents us from it. Intuition is enjoyment, enjoyment is life, not knowledge. ”

“ The process of acquiring knowledge, at first nothing but an indispensable means of mastering things and situations for the purposes of life, has had the same fate as other useful activities: as walking developed into dancing, speaking into singing, so the pursuit of knowledge developed into science. The human mind takes a delight in reducing things to one another, man enjoys this game, no matter whether he can derive any practical advantage from it or not. ”

“ When I look at the blue sky and lose myself in the contemplation of it without thinking that I am enjoying the blue, I am in a state of pure intuition, the blue fills my mind completely, they have become one, it is the kind of union of which the mystic dreams. Bergsonian intuition is the mystical conception of knowledge. ”

“ What has been done in the case of geometry can be done for any other science in so far as it is really scientific, i.e. consists of logically connected propositions: by disregarding the meaning of the symbols we can change the concepts into variables, and the result is a system of propositional functions which represents the pure structure of science, leaving out its content, separating it altogether from reality. When we speak of science, we shall, for the reasons given above, always have in mind theoretical physics, at least for the time being. ”

“ Philosophy is most certainly not a science not even the Science of the sciences, and it has been one of its greatest misfortunes that it has been mistaken for one, and that philosophers have, in outward appearance adopted scientific methods and language. It often makes them a little ridiculous, and there is a good deal of truth in the way in which Schopenhauer describes the contrast between the genuine philosopher and the academic scholar who regards philosophy as a sort of scientific pursuit. ”

“ We know exactly what would have to happen if we wanted to know about the birth of Socrates: we would have to find some old papyrus or inscription in which a reliable and accurate account of the event was given, and it is just an unfortunate chance that such a document, as far as we know, does not exist. But it might exist; we can easily imagine it, and that means that our knowledge of the fact just happens to be impossible, the impossibility is a consequence of accidental circumstances, not of the nature of knowledge itself. ”

“ If any philosopher should be disappointed by an analysis because we had to deny the possibility of real a priori knowledge, he will find enough compensation when we go on to examine the scope of knowledge instead of the validity. Most philosophers have stated with regret that human understanding, however efficiant it may be in some fields, is entirely incompetent in other fields, that the scope of knowledge is restricted to certain parts and aspects of the world, while other parts and aspects must forever remain beyond its reach. ”

“ In reality there is a science of psychology and a very necessary one if we really want to know about the working of "consciousness", but it is also one of the most imperfect sciences, for it appears to be very difficult to know one's self and the laws of consciousness. It seems to require the scientific methods of experiment, observation and comparison, while mere intuition, if it does anything, just furnishes the data which are to be known, but not their knowledge. ”

“ It was this pure geometry, obviously, that Bertrand Russell was thinking about when he gave his famous definition of Mathematics as the Science in which we don't know what we are talking about nor whether what we say is true. As a matter of fact, if the meaning of our symbols is disregarded, we are evidently not speaking of anything particular, and before a meaning is given to them, the question whether we are speaking truly or falsely cannot be asked. ”

“ Can anyone still think that when the poet speaks of a green meadow, the word "green" stands for the content while when the scientist speaks of a green leaf the same word will stand for the structure of green? I think we must be convinced by this time that the word, wherever it occurs in a sentence can never express content, no matter who utters the sentence and for what purpose. ”

“ A theory is a set of hypotheses which may be either true or false and have to be tested by experience. It is not necessary to make hypotheses about meaning, and they would come too late, because we must presuppose meaning in order to formulate any hypothesis. We have not made any assumptions, we have done nothing but formulate the rules which everybody always follows whenever he tries to explain his own meaning and whenever he wants to understand other people's meaning, and which he never actually violates — except when he begins to philosophize. ”

“ If I observe a man using his eyes in a similar way in which I use my own I am justified in believing that he experiences in his consciousness exactly the same kind of sensations as I do when the same objects are presented to my eyes, so that he will be able to fill a given structure with the same content which I have in mind when I try to communicate to him what I have seen. ”

“ We must inform him that, if this is the case there is no meaning in his propositions about a metaphysical external world and that we must continue to use this phrase in the good old innocent sense in which it stands for stars, mountains, and trees, as contrasted with dreams, feelings and wishes which form the "internal" world. We must inform the philosopher that it is not his business to tell us what is real and what is unreal — this must be left to experience and science — but it is his business to tell us what we mean when we judge of a certain thing or event that it is "real". ”

“ Now it is time to remember what we had to say about language and Expression: it embodied the possibility of representing and communicating a fact by a new combination of old symbols. So we conclude: all genuine knowledge is Expression. This is, of course, not a mere coincidence, not just an interesting fact, but it constitutes the very essence of scientific as well as everyday knowledge. ”

“ We know this to be nonsense, and therefore impossible for the language of every day life, art, religion just as well as for science. So science is not inferior to anything else in this respect; on the contrary, it avails itself to the fullest extent of all the possibilities of the one kind of knowledge which is the only kind. Life and art are centered around "enjoyment" of content, for them expression is not the ultimate end, but only a means, and is, accordingly, valued only in so far as it leads to the production (not communication) of certain contents. ”

“ These philosophers might object to my view by asking: How do you know that everything has a logical structure? is it not possible that the world or part of it may be entirely without order? I answer that this question is the result of a misunderstanding. The order of which I speak is of such a general nature that it would be meaningless to speak of anything as not possessing it. To say that a fact has a structure is to assert nothing of it; it is a mere tautological statement. ”

“ The description of a coloured object does not communicate content to any one, whether blind or seeing, but leaves it to him to provide it from his own stock. You will probably say that only the seeing person will really provide "colour", whereas a blind man will provide some other content, and you will assert that the latter, although he will think that he understands the description perfectly well, is in reality very far from it, because the "true" interpretation must be given in terms of "colours", and nothing else can take their place. ”

“ Thus we see that in the case of poetry and art — just as well as in all other cases of human interest and action — we deal only with structure. Ineffable content remains beyond forever. We must not make the mistake (which is really the source of all difficulties here) to think that art would be more wonderful or more perfect if it could express content, and that its inexpressibility must always remain a matter of regret. ”

“ It is of the highest importance to see that in maintaining that all facts must have a structure we are not making any presuppositions about the facts at all, we are saying only that facts are facts, which is, as will probably be admitted, saying nothing about them. Some philosophers have discussed the possibility of the world’s being “irrational”, which probably means that we could have no knowledge of it, form no true propositions about it. ”

“ It is nonsense to contrast with each other the knowledge of the thing and the knowledge of its description. We have seen that genuine knowledge of things consists in their description (in terms of other things) consequently, the highest degree of knowledge of a thing is the most complete, most perfect description of it, and not the thing itself (The thing is not the most perfect of its own descriptions, but something entirely different) . He who wants to know an object as completely as possible, wants an explanation of it, he does not want the object itself. ”

“ It is impossible to discover the truth of a proposition without being acquainted with its meaning. No one can essentially contribute to the progress of science without having before his mind the genuine and final sense of the Truths he is investigating. That is why all great scientists have also been Philosophers. They have been inspired by the philosophic spirit. Nevertheless the distinction must be made, and it has the advantage of giving a satisfactory answer to the endless questions concerning the nature and task of philosophy. ”

“ We can never understand science and knowledge if we do not realise that the question concerning the real nature of a thing is completely and exhaustively answered by giving the structure of the thing, and there is nothing left which ought to be expressed. If you inquire into the nature of gravitations, for instance, Einstein's equations (supposing them to be correct) will give you the answer to any question you can possibly ask about gravitation - you certainly cannot expect more than this, you cannot expect answers to impossible, senseless questions. ”

“ But as soon as we are able to ask questions there is the possibility of expression, and there is logic. It is even misleading, although I have done it myself for the sake of argument, to speak of the "validity of logic", for an invalid logic would not be logic, it would be nonsense.
Once more : the world cannot be logical or irrational — such phrases are nothing but excuses for bad philosophy. Whatever the universe is like — we can describe it by true propositions. ”

“ It will then no longer be a physical science — (for in a physical science all symbols must stand for physical things, or events, they must mean something) — it has become "pure" geometry, something that is of interest to the pure mathematician only, who enjoys transforming expressions into one another without caring what they express; it does not tell us anything about space any more, even if the word "space" should occur in it continually; it has lost all contact with reality; it is a frame, that frames nothing; it is mere structure without content. ”