Quotation
Last reviewed:
“I think I can safely say that nobody understands quantum mechanics.”
Richard Feynman · Thinkers beyond philosophy · Modern · 1965
What does it mean?
He is saying that quantum mechanics is not understood in the way a person wants a picture to be understood, even by people who use it successfully. The usual reading keeps the modesty: calculation is not the same as a comfortable story. A competing reading hears that the theory is optional or empty, which a working physicist was not saying. The sentence is chapter 6 of The Character of Physical Law. Safely say is a joke with a point. The point is the limit of pictorial understanding, not a holiday from the mathematics.
Did Richard Feynman really say this?
The library’s label is Well attested. His English in the Messenger Lectures, in the chapter on the quantum mechanical view of nature. It is a remark about understanding, not a claim that the theory makes no predictions.
Where it comes from
The Character of Physical Law (1965), chapter 6, Probability and Uncertainty
Approximate date: 1965.
How to use it
When a popular book tells a Manchester reading group that nobody understands this, so any picture will do, the sentence has been turned around. He could use the theory. He would not sell a muddle as the same achievement. Ask what the person can calculate, not how mysterious they feel.
A mindset reading
Ignorance of a picture is not ignorance of a result. He distinguishes them. The line is a poor excuse for refusing a calculation you could check.
Understand the philosophy
Chapter 6 is the lecture on probability and uncertainty. The key word is understands, and he means a grasp that feels like a classical picture. Chapter 7 still says a law that disagrees with experiment is wrong. The two chapters are not in a fight. One limits intuition. The other keeps the test.
- knowledge
- mind
FAQ
What does it mean?
He is saying that quantum mechanics is not understood in the way a person wants a picture to be understood, even by people who use it successfully. The usual reading keeps the modesty: calculation is not the same as a comfortable story. A competing reading hears that the theory is optional or empty, which a working physicist was not saying. The sentence is chapter 6 of The Character of Physical Law. Safely say is a joke with a point. The point is the limit of pictorial understanding, not a holiday from the mathematics.
Did Richard Feynman really say this?
Well attested. His English in the Messenger Lectures, in the chapter on the quantum mechanical view of nature. It is a remark about understanding, not a claim that the theory makes no predictions.
Which work is it in?
The Character of Physical Law (1965), chapter 6, Probability and Uncertainty Approximate date: 1965.