Quotation
Last reviewed:
“If it disagrees with experiment it is wrong.”
Richard Feynman · Thinkers beyond philosophy · Modern · 1965
What does it mean?
A guess, however elegant and whoever made it, is wrong if it disagrees with experiment. The usual reading takes the sentence as the blunt end of a three-step method, not as a cult of the laboratory for its own sake. A competing reading hears that only physics counts as knowledge, which the lecture does not claim. He is telling an audience how a new law in that science is sought. The sentence is chapter 7 of The Character of Physical Law. Compute, then compare. Beauty does not get a vote after the comparison fails.
Did Richard Feynman really say this?
The library’s label is Well attested. His English in the Messenger Lectures, chapter 7. He has just described the method: guess a law, compute the consequences, compare them with experiment or experience. Page 156 in the commonly cited MIT Press edition. The rule does not depend on that page number.
Where it comes from
The Character of Physical Law (1965), chapter 7, Seeking New Laws
Approximate date: 1965.
How to use it
A model in a Manchester office that is admired, and that misses the figures you already have, is in the position he calls wrong. The sentence does not tell you which measurement to trust when the measurements conflict. It tells you not to keep the guess out of loyalty.
A mindset reading
Wrong here means the guess failed the comparison, not that the person who guessed is a fool. He expects guesses. He does not expect them to outrank the result.
Understand the philosophy
Chapter 7 is 'Seeking New Laws'. The key sentence is the one on this card, after the guess and the computation. Chapter 6, the quantum remark, is a different claim about understanding, not a cancellation of this rule. The 1974 address is what he thinks you must not do while you are comparing.
- knowledge
- mind
FAQ
What does it mean?
A guess, however elegant and whoever made it, is wrong if it disagrees with experiment. The usual reading takes the sentence as the blunt end of a three-step method, not as a cult of the laboratory for its own sake. A competing reading hears that only physics counts as knowledge, which the lecture does not claim. He is telling an audience how a new law in that science is sought. The sentence is chapter 7 of The Character of Physical Law. Compute, then compare. Beauty does not get a vote after the comparison fails.
Did Richard Feynman really say this?
Well attested. His English in the Messenger Lectures, chapter 7. He has just described the method: guess a law, compute the consequences, compare them with experiment or experience. Page 156 in the commonly cited MIT Press edition. The rule does not depend on that page number.
Which work is it in?
The Character of Physical Law (1965), chapter 7, Seeking New Laws Approximate date: 1965.