Niels Bohr Quotes

Niels Bohr shares poetic, paradox-loving musings about science, physics and truth.

50 quotes

1. We must be clear that when it comes to atoms, language can be used only as in poetry. The poet, too, is not nearly so concerned with describing facts as with creating images and establishing mental connections.

2. The great extension of our experience in recent years has brought light to the insufficiency of our simple mechanical conceptions and, as a consequence, has shaken the foundation on which the customary interpretation of observation was based.

3. Isolated material particles are abstractions, their properties being definable and observable only through their interaction with other systems.

4. What is it that we humans depend on? We depend on our words... Our task is to communicate experience and ideas to others. We must strive continually to extend the scope of our description, but in such a way that our messages do not thereby lose their objective or unambiguous character ... We are suspended in language in such a way that we cannot say what is up and what is down. The word 'reality' is also a word, a word which we must learn to use correctly.

5. For a parallel to the lesson of atomic theory regarding the limited applicability of such customary idealisations, we must in fact turn to quite other branches of science, such as psychology, or even to that kind of epistemological problems with which already thinkers like Buddha and Lao Tzu have been confronted, when trying to harmonize our position as spectators and actors in the great drama of existence.

6. We are all agreed that your theory is crazy. The question that divides us is whether it is crazy enough to have a chance of being correct.

7. Physics is to be regarded not so much as the study of something a priori given, but rather as the development of methods of ordering and surveying human experience. In this respect our task must be to account for such experience in a manner independent of individual subjective judgement and therefor objective in the sense that it can be unambiguously communicated in ordinary human language.

8. There is no quantum world. There is only an abstract physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature...

9. Every valuable human being must be a radical and a rebel, for what he must aim at is to make things better than they are.

10. How wonderful that we have met with a paradox. Now we have some hope of making progress.

11. Two sorts of truth: trivialities, where opposites are obviously absurd, and profound truths, recognised by the fact that the opposite is also a profound truth.

12. An expert is a man who has made all the mistakes which can be made in a very narrow field.

13. Every sentence I utter must be understood not as an affirmation, but as a question.

14. Anyone who is not shocked by quantum theory has not understood it.

15. Some subjects are so serious that one can only joke about them.

16. Truth and clarity are complementary.

17. It is not enough to be wrong, one must also be polite.

18. Never express yourself more clearly than you are able to think.

19. It is better to don't understand something true, than to understand something false.

20. Prediction is very difficult, especially about the future.

21. Stop telling God what to do with his dice.

22. Of course not ... but I am told it works even if you don't believe in it.

23. I am a very Bohring man.

24. I go into the Upanishads to ask questions.

25. It is a great pity that human beings cannot find all of their satisfaction in scientific contemplativeness.

26. Not often in life has a human being caused me such joy by his mere presence as you did.

27. I remember discussions with Bohr which went through many hours till very late at night an 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?

28. One of the favorite maxims of my father was the distinction between the two sorts of truths, profound truths recognized by the fact that the opposite is also a profound truth, in contrast to trivialities where opposites are obviously absurd.

29. An expert is a man who has made all the mistakes which can be made, in a narrow field.

30. An expert is someone who knows some of the worst mistakes, which can be made, in a very narrow field.

31. The opposite of every great idea is another great idea.

32. The meaning of life consists in the fact that it makes no sense to say that life has no meaning.

33. Technology has advanced more in the last thirty years than in the previous two thousand. The exponential increase in advancement will only continue.

34. Anybody who is not shocked by this subject has failed to understand it. [of quantum mechanics]

35. When it comes to atoms, language can be used only as in poetry. The poet, too, is not nearly so concerned with describing facts as with creating images.

36. Every description of natural processes must be based on ideas which have been introduced and defined by the classical theory.

37. It is, indeed, perhaps the greatest prospect of humanistic studies to contribute through an increasing knowledge of the history of cultural development to that gradual removal of prejudices which is the common aim of all science.

38. One thought spectra are marvellous, but it is not possible to make progress there. Just as if you have the wing of a butterfly then certainly it is very regular with the colors and so on, but nobody thought one could get the basis of biology from the coloring of the wing of a butterfly.

39. If you think you understand it, that only shows that you don't know the first thing about it.

40. The very nature of the quantum theory ... forces us to regard the space-time coordination and the claim of causality, the union of which characterizes the classical theories, as complementary but exclusive features of the description, symbolizing the idealization of observation and description, respectively.

41. Address to Albert Einstein: You are not thinking. You are merely being logical.

42. If an idea does not appear bizarre, there is no hope for it.

43. Those who are not shocked when they first come across quantum theory cannot possibly have understood it.

44. Physics is the belief that a simple and consistent description of nature is possible.

45. A physicist is just an atom's way of looking at itself.

46. If quantum mechanics hasn't profoundly shocked you, you haven't understood it yet.

47. If anybody says he can think about quantum physics without getting giddy, that only shows he has not understood the first thing about them.

48. There are trivial truths and the great truths. The opposite of a trivial truth is plainly false. The opposite of a great truth is also true.

49. Predictions are hard, especially abot the future.

50. The old saying of the two kinds of truth. To the one kind belongs statements so simple and clear that the opposite assertion obviously could not be defended. The other kind, the so-called 'deep truths', are statements in which the opposite also contains deep truth.