I saw a sig line one time that said:
“If you can’t explain it to a 6 year old then you really don’t understand it yourself” - A. Einstein
I’ve always liked that quote and have found it to be true more times then not. But I also seem to remember someone (here on SD in fact) saying that it wasn’t Einstein with a 6 year old, it was Feynman and his grandma.
Can any one shed some light and maybe a reference on this?
Thanks!
I can’t find it on the SDMB, but I found this searching Google groups:
A bit more searching turned up this reference to Gleick’s book about Feynman, “Genius”:
Well, if it stumps the SD then regardless of the etymology I’d be willing to accept not only its message, but its source.
Its has a certain feeling of truth and honesty. Like most of things he said.
“If you can’t explain it to your dog, you don’t really understand it yourself.” --Oliver Faltz
The fact that something can’t be explained to freshmen, or 6-year-olds, or dogs does not mean you don’t understand it. It just means they’re not as smart as you are.
I fully realize that either of these statements can be used to defend a variety of bulldung positions. I started to list some of them, but my sticky cynicism bagan to gum up my keyboard. I’m trying to avoid getting that angry these days. If you want to take that bone in your own teeth, well, fine. Run with it. I’m tired, and I’ve had a bad day.
AskNott:
Do you have a cite for your quote?
If you do, perhaps it can shed some light on the question.
If not, then it, and the rest of your diatribe, only show your ignorance.
If you want to complain about your day and how angry you are please help yourself to any of the numerous “blogger” sites availible. There are plenty of people willing to let you spill your guts to no one who cares.
Oliver Faltz is my pseudonym. Ollie will cheerfully say anything I tell him to say. The name comes from the concept of “I love my wife in spite of all-of-her-faults.”
The fact that James Carroll did not understand what I wrote does not, as he suggested, show my ignorance. It shows only that I could not “explain it to a” James Carroll. That doesn’t make me a bad fellow. I’m sure there’s one or two things James Carroll understands that he could not explain to me, or to a college freshman, or to me when was a college freshman long ago.
Now, I think that is being a bit literal with it. 
The Feynman/Einstein story is just a variation on an old Math story which goes like this:
Once [insert name of famous mathematician here] was explaining part of [insert name of famous theorem here] and he said, “The proof of this part is, of course, obvious.”
To which a poor, lost student asked, “But I don’t understand. Why is it obvious, sir?”
[famous mathematician] thinks for a minute.
Then he paces a bit.
Then he leaves the room for fifteen minutes.
Finally, he bursts back into the room saying, “It is obvious! And I’ll tell you why …”
(This is usually told about G.H. Hardy, who is best known to the general public as the mentor to the Indian prodigy Ramanujan.)
JamesCarroll
Its has a certain feeling of truth and honesty. Like most of things he said.
But then it’s such a neat epigram that perhaps you’re letting “it ought to have been said” over-ride a lack of fact. A Google search finds many different versions of what both Einstein and Feynman are claimed to have said. “If you can’t explain it to an 8-year-old … 9-year-old … 6-year-old … your grandmother … a high school student … simply … etc”. The attribution is very murky. And, as AskNott says, it isn’t even true.
This reminds me of an experience my son had in grad school at Temple.
After being in class for several weeks, he took his girlfriend to class (it was encouraged by the professor). Afterwards, he asked her what she thought. She said “I could hardly understand a word they said.” He laughed and told her he was glad to hear her say that since he felt the same way. He made a B in the course.