Werner Heisenberg Quotes & Sayings

Even for the physicist the description in plain language will be a criterion of the degree of understanding that has been reached. — Werner Heisenberg

Many people will tell you that an expert is someone who knows a great deal about the subject. To this I would object that one can never know much about any subject. I would much prefer the following definition: an expert is someone who knows some of the worst mistakes that can be made in the subject, and how to avoid them. — Werner Heisenberg

Science no longer is in the position of observer of nature, but rather recognizes itself as part of the interplay between man and nature. The scientific method ... changes and transforms its object: the procedure can no longer keep its distance from the object. — Werner Heisenberg

Here the attention of the research workers is primarily directed to the problem of reconciling the claims of the special relativity theory with those of the quantum theory. The extraordinary advances made in this field by Dirac ... leave open the question whether it will be possible to satisfy the claims of the two theories without at the same time determining the Sommerfeld fine-structure constant. — Werner Heisenberg

My mind was formed by studying philosophy, Plato and that sort of thing. — Werner Heisenberg

The physicist may be satisfied when he has the mathematical scheme and knows how to use for the interpretation of the experiments. But he has to speak about his results also to non-physicists who will not be satisfied unless some explanation is given in plain language. Even for the physicist the description in plain language will be the criterion of the degree of understanding that has been reached.
Physics and Philosophy — Werner Heisenberg

Every experiment destroys some of the knowledge of the system which was obtained by previous experiments. — Werner Heisenberg

Can quantum mechanics represent the fact that an electron finds itself approximately in a given place and that it moves approximately with a given velocity, and can we make these approximations so close that they do not cause experimental difficulties? — Werner Heisenberg

The first gulp from the glass of natural sciences will turn you into an atheist, but at the bottom of the glass God is waiting for you. — Werner Heisenberg

After the conversations about Indian philosophy, some of the ideas of Quantum Physics that had seemed so crazy suddenly made much more sense. — Werner Heisenberg

The one who insists on never uttering an error must remain silent. — Werner Heisenberg

I think that the discovery of antimatter was perhaps the biggest jump of all the big jumps in physics in our century. — Werner Heisenberg

The reality we can put into words is never reality itself. — Werner Heisenberg

It seems sensible to discard all hope of observing hitherto unobservable quantities, such as the position and period of the electron ... Instead it seems more reasonable to try to establish a theoretical quantum mechanics, analogous to classical mechanics, but in which only relations between observable quantities occur. — Werner Heisenberg

Modern physics has changed nothing in the great classical disciplines of, for instance, mechanics, optics, and heat. Only the conception of hitherto unexplored regions, formed prematurely from a knowledge of only certain parts of the world, has undergone a decisive transformation. This conception, however, is always decisive for the future course of research. — Werner Heisenberg

If nature leads us to mathematical forms of great simplicity and beauty - by forms, I am referring to coherent systems of hypotheses, axioms, etc. - to forms that no one has previously encountered, we cannot help thinking that they are "true," that they reveal a genuine feature of nature ... . You must have felt this too: the almost frightening simplicity and wholeness of the relationships which nature suddenly spreads out before us and for which none of us was in the least prepared. — Werner Heisenberg

Separation of the observer from the phenomenon to be observed is no longer possible. — Werner Heisenberg

An expert is someone who knows some of the worst mistakes that can be made in his subject, and how to avoid them. — Werner Heisenberg

It is seen that both matter and radiation possess a remarkable duality of character, as they sometimes exhibit the properties of waves, at other times those of particles. Now, it is obvious that a thing cannot be a form of wave motion and composed of particles at the same time - the two concepts are too different. — Werner Heisenberg

Quantum theory provides us with a striking illustration of the fact that we can fully understand a connection though we can only speak of it in images and parables. — Werner Heisenberg

The 'path' comes into existence only when we observe it. — Werner Heisenberg

The very act of observing disturbs the system. — Werner Heisenberg

The existing scientific concepts cover always only a very limited part of reality, and the other part that has not yet been understood is infinite. — Werner Heisenberg

Natural science, does not simply describe and explain nature; it is part of the interplay between nature and ourselves. — Werner Heisenberg

There are things that are so serious that you can only joke about them. — Werner Heisenberg

In the history of science, ever since the famous trial of Galileo, it has repeatedly been claimed that scientific truth cannot be reconciled with the religious interpretation of the world. Although I an now convinced that scientific truth is unassailable in its own field, I have never found it possible to dismiss the content of religious thinking as simply part of an outmoded phase in the consciousness of mankind, a part we shall have to give up from now on, Thus in the course of my life I have repeatedly been compelled to ponder on the relationship of these two regions of though, for I have never been able to doubt the reality of that to which they point. — Werner Heisenberg

Nature allows only experimental situations to occur which can be described within the framework of the formalism of quantum mechanics — Werner Heisenberg

I think that modern physics has definitely decided in favor of Plato. In fact the smallest units of matter are not physical objects in the ordinary sense; they are forms, ideas which can be expressed unambiguously only in mathematical language. — Werner Heisenberg

We will have to abandon the philosophy of Democritus and the concept of elementary particles. We should accept instead the concept of elementary symmetries. — Werner Heisenberg

"Uncertainty" is NOT "I don't know." It is "I can't know." "I am uncertain" does not mean "I could be certain." — Werner Heisenberg

Whether we electrons, light quanta, benzol molecules, or stones, we shall always come up against these two characteristics, the corpuscular and the undular. — Werner Heisenberg

You may object that by speaking of simplicity and beauty I am introducing aesthetic criteria of truth, and I frankly admit that I am strongly attracted by the simplicity and beauty of mathematical schemes which nature presents us. You must have felt this too: the almost frightening simplicity and wholeness of the relationship, which nature suddenly spreads out before us. — Werner Heisenberg

The uncertainty relation does not refer to the past; if the velocity of the electron is at first known and the position then exactly measured, the position for times previous to the measurement may be calculated. — Werner Heisenberg

The problems of language here are really serious. We wish to speak in some way about the structure of the atoms. But we cannot speak about atoms in ordinary language. — Werner Heisenberg

The basic idea is to shove all fundamental difficulties onto the neutron and to do quantum mechanics in the nucleus. — Werner Heisenberg

Whether we like it or not, modern ways are going to alter and in part destroy traditional customs and values. — Werner Heisenberg

The more closely you look at one thing, the less closely can you see something else. — Werner Heisenberg

In my paper the fact the XY was not equal to YX was very disagreeable to me. I felt this was the only point of difficulty in the whole scheme ... and I was not able to solve it. — Werner Heisenberg

Every tool carries with it the spirit by which it has been created. — Werner Heisenberg

The German physicists knew at least so much about the manufacture and construction of atomic bombs that it was clear to them that the manufacture of bombs in Germany could not succeed during the war. For this reason, they were spared the moral decision whether they should make an atomic bomb, and they had only worked on the uranium engine. — Werner Heisenberg

If we wanted to construct a basic philosophical attitude from these scientific utterances of Pauli's, at first we would be inclined to infer from them an extreme rationalism and a fundamentally skeptical point of view. In reality however, behind this outward display of criticism and skepticism lay concealed a deep philosophical interest even in those dark areas of reality of the human mind which elude the grasp of reason. And while the power of fascination emanating from Pauli's analyses of physical problems was admittedly due in some measure to the detailed and penetrating clarity of his formulations, the rest was derived from a constant contact with the field of creative processes, for which no rational formulation as yet exists. — Werner Heisenberg

The exact sciences also start from the assumption that in the end it will always be possible to understand nature, even in every new field of experience, but that we may make no a priori assumptions about the meaning of the word understand. — Werner Heisenberg

Revere those things beyond science which really matter and about which it is so difficult to speak. — Werner Heisenberg

One may say that in a state of science where fundamental concepts have to be changed, tradition is both the condition for progress and a hindrance. Hence, it usually takes a long time before the new concepts are generally accepted. — Werner Heisenberg

The conception of objective reality ... has thus evaporated ... into the transparent clarity of mathematics that represents no longer the behavior of particles but rather our knowledge of this behavior. — Werner Heisenberg

Whenever we proceed from the known into the unknown we may hope to understand, but we may have to learn at the same time a new meaning of the word 'understanding. — Werner Heisenberg

A consistent pursuit of classical physics forces a transformation in the very heart of that physics. — Werner Heisenberg

Although the theory of relativity makes the greatest of demands on the ability for abstract thought, still it fulfills the traditional requirements of science insofar as it permits a division of the world into subject and object (observer and observed) and, hence, a clear formulation of the law of causality. — Werner Heisenberg

Where no guiding ideals are left to point the way, the scale of values disappears and with it the meaning of our deeds and sufferings, and at the end can lie only negation and despair. Religion is therefore the foundation of ethics, and ethics the presupposition of life. — Werner Heisenberg

It is true that in quantum theory we cannot rely on strict causality. But by repeating the experiments many times, we can finally derive from the observations statistical distributions, and by repeating such series of experiments, we can arrive at objective statements concerning these distributions. — Werner Heisenberg

It is generally believed that our science is empirical and that we draw our concepts and our mathematical constructs from the empirical data. If this were the whole truth, we should, when entering into a new field, introduce only such quantities as can directly be observed, and formulate natural laws only by means of these quantities. — Werner Heisenberg

The discontinuous 'reduction of the wave packets' which cannot be derived from Schroedinger's equation is ... a consequence of the transition from the possible to the actual. — Werner Heisenberg

By getting to smaller and smaller units, we do not come to fundamental or indivisible units. But we do come to a point where further division has no meaning. — Werner Heisenberg

When I meet God, I am going to ask him two questions: Why relativity ? And why turbulence ? I really believe he will have an answer for the first. — Werner Heisenberg

Unless you stake your life, life will not be won. — Werner Heisenberg

What we observe is not nature itself but nature exposed to our method of questioning. Our scientific work in physics consists in asking questions about nature in the language that we possess and trying to get an answer from experiment by the means that are at our disposal. — Werner Heisenberg

The incomplete knowledge of a system must be an essential part of every formulation in quantum theory. Quantum theoretical laws must be of a statistical kind. To give an example: we know that the radium atom emits alpha-radiation. Quantum theory can give us an indication of the probability that the alpha-particle will leave the nucleus in unit time, but it cannot predict at what precise point in time the emission will occur, for this is uncertain in principle. — Werner Heisenberg

The solution of the difficulty is that the two mental pictures which experiment lead us to form - the one of the particles, the other of the waves - are both incomplete and have only the validity of analogies which are accurate only in limiting cases. — Werner Heisenberg

Therefore, the two processes, that of science and that of art, are not very different. Both science and art form in the course of the centuries a human language by which we can speak about the more remote parts of reality, and the coherent sets of concepts as well as the different styles of art are different words or groups of words in this language. — Werner Heisenberg

It will never be possible by pure reason to arrive at some absolute truth. — Werner Heisenberg

The ontology of materialism rested upon the illusion that the kind of existence, the direct "actuality" of the world around us, can be extrapolated into the atomic range. This extrapolation is impossible, however. — Werner Heisenberg

In general, scientific progress calls for no more than the absorption and elaboration of new ideas- and this is a call most scientists are happy to heed. — Werner Heisenberg

Science clears the fields on which technology can build. — Werner Heisenberg

The violent reaction on the recent development of modern physics can only be understood when one realises that here the foundations of physics have started moving; and that this motion has caused the feeling that the ground would be cut from science. — Werner Heisenberg

Not only is the Universe stranger than we think, it is stranger than we can think. — Werner Heisenberg

The world thus appears as a complicated tissue of events, in which connections of different kinds alternate or overlap or combine and thereby determine the texture of the whole. — Werner Heisenberg

The more precise the measurement of position, the more imprecise the measurement of momentum, and vice versa. — Werner Heisenberg

[T]he atoms or elementary particles themselves are not real; they form a world of potentialities or possibilities rather than one of things or facts. — Werner Heisenberg

The structure underlying the phenomena is not given by material objects like the atoms of Democritus but by the form that determines the material objects. The Ideas are more fundamental than the objects. — Werner Heisenberg

I remember discussions with Bohr which went through many hours till very late at night and ended almost in despair; and when at the end of the discussion I went alone for a walk in the neighbouring park I repeated to myself again and again the question: Can nature possibly be so absurd as it seemed to us in these atomic experiments? — Werner Heisenberg

The uncertainty principle refers to the degree of indeterminateness in the possible present knowledge of the simultaneous values of various quantities with which the quantum theory deals; it does not restrict, for example, the exactness of a position measurement alone or a velocity measurement alone. — Werner Heisenberg

Every word or concept, clear as it may seem to be, has only a limited range of applicability. — Werner Heisenberg

Only a few know, how much one must know to know how little one knows. — Werner Heisenberg

The Same organizing forces that have shaped nature in all her forms are also responsible for the structure of our minds. — Werner Heisenberg

The positivists have a simple solution: the world must be divided into that which we can say clearly and the rest, which we had better pass over in silence. But can anyone conceive of a more pointless philosophy, seeing that what we can say clearly amounts to next to nothing? If we omitted all that is unclear, we would probably be left completely uninteresting and trivial tautologies. — Werner Heisenberg

There is a fundamental error in separating the parts from the whole, the mistake of atomizing what should not be atomized. Unity and complementarity constitute reality. — Werner Heisenberg

In America, it was decided to attempt the production of atomic bombs with an effort that would constitute a large part of the collective American war effort. In Germany, an effort one thousandth the scale of the American was applied to the problem of producing atomic energy that would drive engines. — Werner Heisenberg

Reports in Washington show that our reasoning was just like that of your physicists. With all this information available, at least to privileged persons, I cannot understand why it is generally held in the United States that we completely missed the basic principle of the bomb until after Hiroshima. — Werner Heisenberg

It is probably true quite generally that in the history of human thinking the most fruitful developments frequently take place at those points where two different lines of thought meet. These lines may have their roots in quite different parts of human nature, in different times or different cultural environments or different religious traditions: hence if they actually meet, that is, if they are at least so much related to each other that a real interaction can take place, then one may hope that new and interesting developments may follow. — Werner Heisenberg

Nature is made in such a way as to be able to be understood. Or perhaps I should put it-more correctly-the other way around, and say that we are made in such a way as to be able to understand Nature. — Werner Heisenberg

I would like to mention astrophysics; in this field, the strange properties of the pulsars and quasars, and perhaps also the gravitational waves, can be considered as a challenge. — Werner Heisenberg

It was about three o'clock at night when the final result of the calculation [which gave birth to quantum mechanics] lay before me ... At first I was deeply shaken ... I was so excited that I could not think of sleep. So I left the house ... and awaited the sunrise on top of a rock. — Werner Heisenberg

Thus, the more precisely the position is determined, the less precisely the momentum is known, and conversely. — Werner Heisenberg