Werner Heisenberg Quotes (1901-1976)

“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.”

“Art is always an idealization; the ideal is different from reality—at least from the reality of the shadows, as Plato would have put it—but idealization is necessary for understanding.”

“After these conversations with Tagore some of the ideas that had seemed so crazy suddenly made much more sense. That was a great help for me.”

“The theory of relativity... showed in a conclusive way that the concept of the ether as a substance, to which Maxwell's equations refer, had to be abandoned. ...the result was that the fields had to be considered as an independent reality.”

“[E]ven in the most precise part of sience, in mathematics, we cannot avoid using concepts that involve contradictions. ...[I]t is well known that the concept of infinity leads to contradictions that have been analyzed, but it would be practically impossible to construct the main parts of mathematics without this concept.”

“[W]ith Thales... Aristotle ascribes the statement: "Water is the material cause of all things." This... expresses, as Nietzsche... pointed out, three fundamental ideas of philosophy. First, ...the material cause of all things; second, ...that this ...be answered in conformity with reason, without ...myths or mysticism; third, ...that ...it must be possible to reduce everything to one principle.”

“The third closed system of concepts and axioms has its origin in the phenomena of electricity and magnetism and has reached its final form in the first decade of the twentieth century through the work of Lorentz, Einstein and Minkowski. It comprises electrodynamics, special relativity, optics, magnetism, and one may include the de Broglie theory of matter waves of all different sorts of elementary particles, but not the wave theory of Schrodinger.”

“[I]n the nineteenth century, even the theory of heat could be reduced to mechanics by the assumption that heat really consists of a complicated statistical motion of the smallest parts of matter. By combining the concepts of the mathematical theory of probability with the concepts of Newtonian mechanics Clausius, Gibbs and Boltzmann were able to show that the fundamental laws in the theory of heat could be interpreted as statistical laws following from Newton's mechanics when applied to very complicated mechanical systems.”

“[H]ow free are we in choosing the concepts for formulating our questions? Any scientific work can only be defined by formulating the questions... But in order to formulate the questions we need concepts by which we hope to get hold of the phenomena. These concepts are usually taken from the past history of science; they suggest already a possible picture of the phenomena. But if we are going to enter into a new realm of phenomena, these concepts may act as a collection of prejudices, which hamper progress... Even then we have to use concepts, and we can't help falling back on those given to us by tradition.”

“There is an enormous difference between modern science and Greek philosophy, and that is just the empiristic attitude... Since the time of Galileo and Newton, modern science has been based upon a detailed study of nature and upon the postulate that only such statements should be made, as have been verified or at least can be verified by experiment. The idea that one can single out some events from nature by an experiment... to find out what is the constant law in the continuous change, did not occur to the Greek philosophers. Therefore, modern science has from its beginning stood on a much more modest, but at the same time much firmer, basis than ancient philosophy. Therefore, the statements of modern physics are in some way meant much more seriously than the statements of Greek philosophy.”

“The way in which the convergent mathematical schemes did not fulfill the requirements of relativity and quantum theory was... interesting. ...[O]ne scheme ...interpreted in terms of actual events in space and time, led to a...time reversal... The physicists are convinced... that the processes... do not occur in nature... if... separated by measurable distance in space and time. ...If we assume that the laws of nature do contain a third universal constant... of the order of 10-13 cm, then... our usual concepts... apply only to regions in space and time that are large compared to the universal constant. We should... be prepared for phenomena of a qualitatively new character when we... approach regions... smaller than the nuclear radii. The phenomenon of time reversal... might therefore belong to these smallest regions.”

“Newton's system was for a long time considered as final and the task... seemed simply to be an expansion.... From the theory of the motion of mass points one could go over to the mechanics of solid bodies, to rotatory motions, and one could treat the continuous motion of fluid or the vibrating motion of an elastic body. All these... were gradually developed... with the evolution of mathematics, especially of the differential calculus... checked by experiments. Acoustics and hydrodynamics became a part of mechanics. Another science... was astronomy. Improvements... led to... more accurate determinations of the motions of the planets... When the phenomena of electricity and magnetism were discovered, the... forces were compared to the gravitational forces... Finally, in the nineteenth century, even the theory of heat could be reduced...”

“[W]ith Thales... Aristotle ascribes the statement: "Water is the material cause of all things." This... expresses, as Nietzsche... pointed out, three fundamental ideas of philosophy. First, ...the material cause of all things; second, ...that this ...be answered in conformity with reason, without ...myths or mysticism; third, ...that ...it must be possible to reduce everything to one principle.”

“[P]hysicists... try to find a fundamental law of motion for matter from which all elementary particles and their properties can be derived mathematically. This fundamental equation... may refer either to waves of a known type... or to waves... which have nothing to do with any of the known waves or elementary particles. In the first case it would mean that all other elementary particles can be reduced in some way to a few sorts of "fundamental" elementary particles... In the second case all different elementary particles could be reduced to some universal substance... energy or matter, but none of the... particles could be preferred... as... more fundamental. The latter... corresponds to... Anaximander, and... this view is the correct one.”

“After these conversations with Tagore some of the ideas that had seemed so crazy suddenly made much more sense. That was a great help for me.”

“With regard to this question modern physics takes a definite stand against the materialism of Democritus and for Plato and the Pythagoreans. The elementary particles are certainly not eternal and indestructible units of matter, they can actually be transformed into each other. … The elementary particles in Plato's Timaeus are finally not substance but mathematical forms.”

“Galileo argued that nature, God's second book, is written in mathematical letters... Kepler is even more explicit in his work on world harmony; he says: God created the world in accordance with his ideas of creation. These ideas are the pure archetypal forms which Plato termed Ideas, and they can be understood by man as mathematical constructs. They can be understood by Man, because Man was created in the spiritual image of God. Physics is reflection on the divine Ideas of Creation, therefore physics is divine service.”

“Greek philosophy returned for some time to the concept of the One in the teachings of Parmenides... His most important contribution... was, perhaps, that he introduced a purely logical argument into metaphysics. "One cannot know what is not—that is impossible—nor utter it; for it is the same thing that can be thought and that can be." Therefore, only the One is, and there is no becoming or passing away. Parmenides denied the existence of empty space for logical reasons. Since all change requires empty space... he dismissed change as an illusion.”

“[I]t looks in the first moment as though his central concept of the "synthetic judgements a priori" had been completely annihilated by the discoveries of our century. The theory of relativity has... revealed entirely new features of space and time, of which nothing is seen in Kant's a priori forms of pure intuition. The law of causality is no longer applied in quantum theory and the law of conservation of matter is no longer true for the elementary particles. Obviously Kant could not have foreseen the new discoveries, but since he was convinced that his concepts would be "the basis of any future metaphysics that can be called science" it is interesting to see where his arguments have been wrong.”

“[I]n the Copenhagen interpretation of quantum theory we can indeed proceed without mentioning ourselves as individuals, but we cannot disregard the fact that natural science is formed by men. Natural science does not simply describe and explain nature; it is part of the interplay between nature and ourselves; it describes nature as exposed to our nature of questioning. This was a possibility of which Descartes could not have thought, but it makes a sharp separation between the world and the I impossible. If one follows the great difficulty which even eminent scientists like Einstein had in understanding and accepting the Copenhagen interpretation... one can trace the roots... to the Cartesian partition....it will take a long time for it [this partition] to be replaced by a really different attitude toward the problem of reality.”

“Empedocles... changed... [Greek philosophy] from monism to a kind of pluralism. To avoid the difficulty that one primary substance cannot explain the variety of things and events, he assumed four basic elements, earth, water, air and fire.... mixed... and separated by... Love and Strife. Therefore, these latter two... are responsible for the imperishable change. Empedocles describes the formation of the world... First, ...the infinite Sphere of the One, as in the philosophy of Parmenides. But in the primary substance all the four "roots" are mixed... by Love. Then, when Love is passing out and Strife coming in, the elements are partially separated and partially combined. After that the elements are completely separated and Love is outside the World. Finally, Love is bringing the elements together again and Strife is passing out, so... we return to the original Sphere. This doctrine... represents... a more materialistic view... Here for the first time... a few [fundamentally different] substances... explains the infinite variety of things and events. Pluralism never appeals to those who are wont to think in fundamental principles. But it is a reasonable... compromise, which avoids the difficulty of monism and allows... some order.”

“In... Heraclitus... Becoming occupies the foremost place. He regarded that which moves, the fire, as the basic element. The difficulty, to reconcile the... one fundamental principle with the infinite variety of phenomena, is solved... by recognizing... strife of... opposites is... a kind of harmony. ...[T]he world is ...one and many ..."the opposite tension" of ...opposites ...constitutes the unity of the One. He says: "...war is common to all and strife is justice ...all things come into being and pass away through strife." ...[T]hat infinite and eternal undifferentiated Being ...cannot ...explain the infinite variety of things. This leads to the antithesis of Being and Becoming and ...to the solution of Heraclitus ...change ...is the fundamental principle; the "imperishable change, that renovates the world," as the poets have called it. But ...change ...is not a material cause and therefore is represented ...by the fire ...both matter and a moving force. ...[P]hysics is ...extremely near to ...Heraclitus ...[i]f we replace ..."fire" by ..."energy" ...Energy is a substance, since its total ...does not change, and ...elementary particles can ...be made from this ...Energy may be called the fundamental cause for all change in the world. ...Energy is ...that which moves; it may be called the primary cause of all change, and ...can be transformed into matter or heat or light. The strife between opposites in the philosophy of Heraclitus can be found in the strife between two different forms of energy.”

“Heisenberg's name will always be associated with his theory of quantum mechanics, published in 1925, when he was only 23 years old. For this theory and the applications of it which resulted especially in the discovery of allotropic forms of hydrogen, Heisenberg was awarded the Nobel Prize for Physics for 1932. His new theory was based only on what can be observed, that is to say, on the radiation emitted by the atom. We cannot, he said, always assign to an electron a position in space at a given time, nor follow it in its orbit, so that we cannot assume that the planetary orbits postulated by Niels Bohr actually exist. Mechanical quantities, such as position, velocity, etc. should be represented, not by ordinary numbers, but by abstract mathematical structures called "matrices" and he formulated his new theory in terms of matrix equations.”

“When he arrived he looked like a simple peasant boy, with short, fair hair, clear bright eyes and a charming expression. He took his duties as an assistant more seriously than Pauli and was a great help to me. His incredible quickness and acuteness of apprehension has always enabled him to do a colossal amount of work without much effort; he finished his hydrodynamic thesis, worked on atomic problems partly alone, partly in collaboration with me, and helped me to direct my research students.”

“In 1929, Heisenberg spent some time in India as the guest of the celebrated Indian poet Rabindranath Tagore, with whom he had long conversations about science and Indian philosophy. This introduction to Indian thought brought Heisenberg great comfort, he told me. He began to see that the recognition of relativity, interconnectedness, and impermanence as fundamental aspects of physical reality, which had been so difficult for himself and his fellow physicists, was the very basis of the Indian spiritual traditions. “After these conversations with Tagore,” he said, “some of the ideas that had seemed so crazy suddenly made much more sense. That was a great help for me.””

“We gaze continually at the world and it grows dull in our perceptions. Yet seen from the another's vantage point, as if new, it may still take our breath away. Come... dry your eyes, for you are life, rarer than a quark and unpredictable beyond the dreams of Heisenberg. Come, dry your eyes. And let's go home.”

“Heisenberg in cattedra / spiegava il Principio di indeterminazione / a una platea di eletti. / In un angolo Fermi e Dirac / si guardarono un attimo sbigottiti / poi si scambiarono brevi formule / scritte sui palmi delle mani”

“In 1925, the world view of physics was a model of a great machine composed of separable interacting material particles. During the next few years, Schrodinger and Heisenberg and their followers created a universe based on superimposed inseparable waves of probability amplitudes. This new view would be entirely consistent with the Vedantic concept of All in One.”

“From 1946 onward, as Germany's leading physicist, he had two disappointments. His efforts to bring scientists into government failed, and his scientific work, offering suggestions for a new unified field theory, was not generally accepted.”

“J. Robert Oppenheimer: You're talking about turning theory into a practical weapons system faster than the Nazis. Leslie Groves: Who have a twelve month head start. J. Robert Oppenheimer: Eighteen. Leslie Groves: How could you possibly know that? J. Robert Oppenheimer: Our fast neutron research took six months. The man they've undoubtedly put in charge will have made that leap instantly. Leslie Groves: Who do you think they put in charge? J. Robert Oppenheimer: Werner Heisenberg. He has the most intuitive understanding of atomic structure I've ever seen. Leslie Groves: You know his work? J. Robert Oppenheimer: I know him. Just like I know Walter Bothe, von Weizsäcker, Diebner... In a straight race, the Germans win. We've got one hope. Leslie Groves: Which is? J. Robert Oppenheimer: Antisemitism. Leslie Groves: What? J. Robert Oppenheimer: Hitler called quantum physics "Jewish science", said it right to Einstein's face. Our one hope is that Hitler is so, so blinded by hate that he's denied Heisenberg proper resources, because it'll take vast resources.”