Two very similar-sounding quotes have come to my ear, both supposedly said by Albert Einstein.

The first quote is:

“If you can't explain it to a six year old, you don't understand it yourself.” ― Albert Einstein

The second quote is:

“If you can't explain it simply, you don't understand it well enough.” ― Albert Einstein

The close similarity between them could point towards them being the very same quote in misquoted versions.

Which did Albert Einstein actually say? If any...

  • 3
    It was shown in the Skeptics SE that no, he did not state the first quote.
    – CGCampbell
    Jan 29, 2017 at 4:19
  • 1
    This is covered fairly well in the Skeptics question. Any answer here would just be unnecessarily repeating those answers.
    – justCal
    Jan 29, 2017 at 16:09
  • Rule of thumb: if a quotation lacks full attribution (place, date, occasion, name of book, names of correspondents etc) it is safest to treat it as a fake. Jan 31, 2017 at 15:17
  • 1
    Hello @MarkC.Wallace. No further research into this question has been done since it was posted a year ago... And there is no need; the answer is fulfilling.
    – Steeven
    Feb 8, 2018 at 15:09
  • 3
    No wonder so many six years old can understand special relativity.
    – Greg
    Feb 8, 2018 at 15:12

1 Answer 1


Looking over the various discussions of these and other similar quotes, leads to the conclusion that Einstein probably did not say any of these, exactly. I have found no direct attribution to Einstein of any of these quotes of 'six-year olds','barmaids' or 'grandmas' is mentioned. Of course you cant prove something doesn't exist.

The closest, earliest article I find that these modern quotes seem to be based on is in the 1962 book New Perspectives in Physics, where the author states that Einstein, when discussing theories,

...ought to lend themselves to so simple a description "that even a child could understand..."

This seems the closest to most of the modern 'quotes'

That these quotes are all paraphrasing Einstein I do not,however, doubt. A couple of earlier sources show this attitude towards trying to express his theories, and science in general, in a simple manner.

---From the 1938 book,The Evolution of Physics , published by Leopold Infeld, Albert Einstein :

Most of the fundamental ideas of science are essentially simple, and may, as a rule, be expressed in a language comprehensible to everyone.

---Another, earlier yet quote shows Einsteins concern with simplicity in science and his theory

... Its great value lies in the logical simplicity with which it explains apparently conflicting facts in the operation of natural law It provides a more simple method. Hitherto science has been burdened by many general assumptions of a complicated nature.

The above was published April 8, 1921 in an interview labeled "Prof. Einstein--The Poet in Science"

So, unless someone finds an actual, published quotation, my conclusion would be that these quotes are all modern paraphrasing of things Einstein did, at various times state. They just aren't his words.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.