Niels Bohr Quotes
Niels Henrik David Bohr was a Danish physicist who made foundational contributions to atomic theory and quantum mechanics. His 1913 model of the hydrogen atom introduced quantization into atomic structure, and his later principles of complementarity and correspondence helped to articulate the philosophical foundations of the new physics. The quotes below are attributed to Niels Bohr, organized by topic.
Browse Niels Bohr by topic
Niels Bohr on Knowledge
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“An expert is a person who has made all the mistakes that can be made in a very narrow field.”
As quoted by Edward Teller , in Dr. Edward Teller's Magnificent Obsession by Robert Coughlan, in LIFE magazine (6 September 1954), p. 62 | Variant: An expert is a man who has made all the mistakes which can be made in a very narrow field. As quoted by Edward Teller (10 October 1972), and A Dictionary of Scientific Quotations (1991) by Alan L. Mackay, p. 35 -
Attributed to Niels Bohr:
“Prediction is very difficult, especially about the future.”
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“Those who are not shocked when they first come across quantum theory cannot possibly have understood it.”
In a 1952 conversation with Heisenberg and Pauli in Copenhagen; quoted in Heisenberg, Werner, Physics and Beyond . (New York: Harper & Row, 1971) p. 206. -
“In a 1952 conversation with Heisenberg and Pauli in Copenhagen; quoted in Heisenberg, Werner, Physics and Beyond . (New York: Harper & Row, 1971) p. 206.”
Those who are not shocked when they first come across quantum theory cannot possibly have understood it. -
“Niels Bohr's speech at the Nobel Banquet in Stockholm (December 10, 1922)”
The grand discoveries which scientific experiment yielded at and about the turn of the century, in which investigators in many countries took an eminent part and which were destined all unexpectedly to give us a fresh insight into the structure of atoms, were due in the first instance, as all are aware, to the work of the great investigators of the English school, Sir Joseph Thomson and Sir Ernest -
“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.”
Niels Bohr , "Atomic Physics and the Description of Nature" (1934) -
“Isolated material particles are abstractions , their properties being definable and observable only through their interaction with other systems .”
Atomic Physics and the Description of Nature" (1934)
Niels Bohr on Nature
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“Anyone who is not shocked by quantum theory has not understood it.”
As quoted in Meeting the Universe Halfway (2007) by Karen Michelle Barad, p. 254, with a footnote citing The Philosophical Writings of Niels Bohr (1998). | Variants: Those who are not shocked when they first come across quantum mechanics cannot possibly have understood it. Those who are not shocked when they first come across quantum theory cannot possibly have understood it. Anyone who is not sho -
“In his first meeting with Werner Heisenberg in early summer 1920, in response to questions on the nature of language, as reported in Discussions about Language (1933); quoted in Defense Implications of International Indeterminacy (1972) by Robert J. Pranger, p. 11, and Theorizing Modernism : Essays in Critical Theory (1993) by Steve Giles, p. 28”
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. -
“Even the mathematical framework helps nothing, I would first like to understand how Nature avoids the contradictions. (1927)”
Quoted in Werner Heisenberg: Die Sprache der Atome (2010) by H. Rechenberg, p. 564. -
“Niels Bohr , "Atomic Physics and the Description of Nature" (1934)”
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. -
“Atomic Physics and the Description of Nature" (1934)”
Isolated material particles are abstractions , their properties being definable and observable only through their interaction with other systems .
Niels Bohr on Truth
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“The opposite of a profound truth may well be another profound truth.”
Two sorts of truth: profound truths recognized by the fact that the opposite is also a profound truth, in contrast to trivialities where opposites are obviously absurd. -
“We must be clear that when it comes to atoms, language can be used only as in poetry.”
In his first meeting with Werner Heisenberg in early summer 1920, in response to questions on the nature of language, as reported in Discussions about Language (1933); quoted in Defense Implications of International Indeterminacy (1972) by Robert J. Pranger, p. 11, and Theorizing Modernism : Essays in Critical Theory (1993) by Steve Giles, p. 28
Things actually not said by Niels Bohr
A number of widely-shared lines are circulated as Niels Bohr but are in fact from someone else. Did Niels Bohr say these? No. Each entry below pairs the line with the person who actually wrote it.
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Did Niels Bohr say this? No.
“Everything we call real is made of things that cannot be regarded as real.”
This quote is commonly attributed to philosophers but its actual source is uncertain or unverified in the standard reference works. Wikiquote's note on this attribution: Often attributed to Bohr online, and in some books like Our Mathematical Universe by Max Tegmark ( p. 157 ) and The Great Unknown: Seven Journeys to the Frontiers of Science by Marcus du Sautoy ( p. 99 ), the quote is actually from John Gribbin's book In Search of Schrodinger's Cat: Quantum Physics
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Did Niels Bohr say this? No.
“Stop telling God what to do with his dice.”
A response to Einstein 's assertion that " God doesn't play dice "; a similar statement is attributed to Enrico Fermi Variant: Einstein, don't tell God what to do. Variant: Don't tell God what to do with his dice. Variant: You ought not to speak for what Providence can or can not do. – As described in The Physicists: A generation that changed the world (1981) by C. P. Snow, p. 84 In his chapter on the fifth Solvay Conference (1927), biographer Konrad Kleinknecht writes: 'To his [Einsteins] credo "God does not play dice," Bohr countered, "but it cannot be our task to dictate to God how he should govern the world."' Einstein and Heisenberg: The Controversy Over Quantum Physics , Springer… (Disputed.)
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Did Niels Bohr say this? No.
“Of course not ... but I am told it works even if you don't believe in it.”
Reply to a visitor to his home in Tisvilde who asked him if he really believed a horseshoe above his door brought him luck, as quoted in Inward Bound : Of Matter and Forces in the Physical World (1986) by Abraham Pais, p. 210 In most published accounts of this anecdote such was Bohr's reply to his friend, but in one early account, in The Interaction Between Science and Philosophy (1974) by Samuel Sambursky, p. 357, Bohr was at a friend's house and asked "Do you really believe in this?" to which his friend replied "Oh, I don't believe in it. But I am told it works even if you don't believe in it." In his book Physics and Beyond , Werner Heisenberg presented the anecdote as one that Bohr had… (Disputed.)