Moritz Schlick

“ No rule of expression presupposes any law or regularity in the world (which is the condition of ‘experience’ as Hume and Kant use the word) , but it does presuppose data and situations, to which names can be attached. The rules of language are rules of the application of language; so there must be something to which it can be applied. Expressibility and verifiability are one and the same thing. There is no antagonism between logic and experience. Not only can the logician be an empiricist at the same time; he must be one if he wants to understand what he himself is doing. ”

“ Nobody wants to know all the facts, and it is not important to know them : the really essential principles of the universe reveal themselves at any time and any place. I do not suggest, of course, that they lie open at first glance, but they can always be discovered by the careful and penetrating methods of science.
How can I prove my point ? What assures us that the impossibility of answering questions never belongs to the question as such, is never a matter of principle, but is always due to accidental empirical circumstances, which may some day change ? ”

“ The position of this philosophy is unassailable, because it rests on the acknowledgment of the hardest facts and the study of the strictest logic. On these foundations our Philosophy of Experience stands very securely as on a firm rock amidst a wild sea of various philosophical opinions. It is neither skeptical nor dogmatic, it cannot interfere with science or with human values; its only object is understanding. Only in this way can it attain that serene attitude which belongs to all genuine philosophy: the attitude of Wisdom. ”

“ There has never been any other way, and it would be a grave error to suppose that we believe we have discovered a new conception of meaning which is contrary to common opinion and which we want to introduce into philosophy. On the contrary, our conception is not only entirely in agreement with, but even derived from, common sense and scientific procedure. Although our criterion of meaning has always been employed in practice, it has very rarely been formulated in the past, and this is perhaps the only excuse for the attempts of so many philosophers to deny its feasibility. ”

“ They will each approach the study of the history of philosophy with different feelings. The historian will be excited to the greatest enthusiasm by the great works of the thinkers of all times, by the spectacle of the immense mental energy and imagination, zeal and unselfishness which they have devoted to their creations, and the historian will derive the highest enjoyment from all of these achievements. The philosopher, of course, when he studies the history of philosophy will also be delighted, and he cannot help being inspired by the wonderful display of genius throughout all the ages. ”

“ It is a truly fundamental issue. Kant spoke of this question as one of the three great questions which metaphysics has to answer. No other problem causes such a sharp division between the various schools of philosophy and the answer given to this question characterizes the philosophical systems and mental attitudes better than anything else. We find within ourselves a thirst for knowledge, a desire to explain, a craving for answers to endless questions; and every one who thinks has some moments in his life when he asks himself. ”

“ 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. ”

“ All great philosophical issues that have been discussed since the time of Parmenides to our present day are of one of two kinds; we can either give them a definite meaning by careful and accurate explanations and definitions, and then we are sure that they are soluble in principle, although they may give the scientist the greatest trouble and may even never be solved on account of unfavourable empirical circumstances, or we fail to give them any meaning, and then they are no questions at all. Neither case need cause uneasiness for the philosopher. ”

“ If I have myself used the phrase that knowledge deals only with form, the "only" must not be understood as having a restrictive meaning, it is just meant to indicate a contrast with certain other current views. Not for one moment must we allow ourselves to think, or even to speak as if there were two realms in the world, a realm of form and a realm of content and that only the former could be known, whereas unfortunately our powers of knowledge were too weak to penetrate into the realm of content, so that we were forever condemned to stand longingly at its gate. ”

“ But he will not be able to rejoice at the sight that philosophy presents to him with exactly the same feelings as the historian. He will not be able to enjoy the thoughts of ancient and modern times without being disturbed by feelings of an entirely different nature.
The philosopher cannot be satisfied to ask, as the historian would ask of all the systems of thought - are they beautiful, are they brilliant, are they historically important? ”

“ Why should we suppose that there would be any difference if all living beings on our planet, or indeed everywhere in the universe, were extinguished? There can be no doubt that on the strength of empirical evidence the existence of living beings is no necessary condition for the existence of the rest of the world.
The question 'Will the world go on existing after I am dead?' has no meaning unless it is interpreted as asking 'Does the existence of the stars etc.
depend upon the life or death of a human being?', and this question is answered in the negative by experience. ”

“ 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. ”

“ He sits in his library, he consults innumerable books, he works at his desk and studies various opinions of many philosophers as a historian would compare his different sources, or as a scientist would do while engaged in some particular pursuit in any special domain of knowledge; he has all the bearing of a scientist and really believes that he is using in some way the scientific method, only doing so on a more general scale. He regards philosophy as a more distinguished and much nobler science than the others, but not as essentially different from them. ”

“ To regret the impossibility of metaphysics becomes impossible; it would be the same as regretting the impossibility of a round square.
All real questions (i. e. those combinations of words to which we can possibly give the meaning of a question) can in principle be answered (“There is no ‘Riddle of the Universe’,” as Ludwig Wittgenstein has put it) , and they can be answered by experience only, by the methods of science. A heavy burden is taken from Philosophy, and it cannot quarrel any more with science. ”

“ I propose to call ‘empirically possible’ anything that does not contradict the laws of nature. This is, I think, the largest sense in which we may speak of empirical possibility; we do not restrict the term to happenings which are not only in accordance with the laws of nature but also with the actual state of the universe (where ‘actual’ might refer to the present moment of our own lives, or to the condition of human beings on this planet, and so forth) . ”

“ 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 ! ”

“ But this hope is in vain, for we can find reasons why philosophy has failed, and must fail, to produce lasting scientific results as science has done. If these reasons are good then we shall be justified in not trusting in any system of philosophy, and in believing that no such system will come forward in the future.
Let me say at once that these reasons do not lie in the difficulty of the problems with which philosophy deals; neither are they to be found in the weakness and incapacity of human understanding. ”

“ 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. ”