“We are trying to prove ourselves wrong as quickly as possible”: did Feynman say it?

What Feynman said

“But experimenters search most diligently, and with the greatest effort, in exactly those places where it seems most likely that we can prove our theories wrong. In other words we are trying to prove ourselves wrong as quickly as possible, because only in that way can we find progress.”

Source: Richard Feynman, The Character of Physical Law (the 1964 Messenger Lectures at Cornell; BBC 1965, MIT Press paperback 1967), chapter 7, “Seeking New Laws”, p. 158.

Key findings

The sentence is Feynman’s, word for word, from the last of his 1964 Messenger Lectures at Cornell, printed in The Character of Physical Law, chapter 7, page 158 of the MIT Press paperback.

In context he is describing experimenters: they look hardest “in exactly those places where it seems most likely that we can prove our theories wrong”.

A few lines earlier he gives the reason: a theory can be proved wrong but never proved right. “We never are definitely right, we can only be sure we are wrong.”

It’s the same lecture, two pages on, as the famous “if it disagrees with experiment it is wrong”.

Where it comes from

In November 1964 Feynman gave the Messenger Lectures at Cornell, seven lectures that the BBC broadcast on BBC-2 and printed as a transcript, The Character of Physical Law. The last lecture, “Seeking New Laws”, is his description of how physics actually finds things out. It’s the lecture that gave us “if it disagrees with experiment it is wrong”, which we checked here.

Two pages later, on page 158 of the MIT Press paperback, comes this one. We read it in a full-text scan of the book.

What he was talking about

First he explains why science can never be sure it’s right. You guess a law, compute its consequences, and compare them with experiment. If they agree, “The theory is then right? No, it is simply not proved wrong.” Newton’s gravity survived for centuries, he says, until “the slight error of the motion of Mercury was observed.” And then: “We never are definitely right, we can only be sure we are wrong.”

That sets up the sentence. One way to stop science, he says, would be to do experiments only where you already know the law works. “But experimenters search most diligently, and with the greatest effort, in exactly those places where it seems most likely that we can prove our theories wrong. In other words we are trying to prove ourselves wrong as quickly as possible, because only in that way can we find progress.”

A detail the quote leaves out

The “we” is mostly experimenters, and he’s talking about fundamental laws. He goes on to say that in 1964 nobody knew where to look for trouble in low-energy physics, so “all the experiments today in this field of finding out a new law, are of high energy.” High energy was where the known laws were least tested, so that was where they were most likely to break.

Our take

Real, word for word. It works as a general motto, and Feynman would probably have liked it used that way, but in the original it’s a precise description of a strategy: aim your effort at the spot where you’re most likely to be wrong. If you quote it, cite The Character of Physical Law, chapter 7.

How we check a quote

We look for the original: the book and page, the lecture, the letter, the recording or the report. Real means we found the words in Feynman’s own work. Paraphrased means he said something close, but not those words. Misattributed means someone else said it, or it first appears somewhere that isn’t Feynman. No reliable source found means we couldn’t trace it to any original. Quotations are kept short and come with our own commentary. If you have a source we missed, write to us via the imprint and we’ll update the page.

“We are trying to prove ourselves wrong as quickly as possible”: did Feynman say it?

Verdict: Real