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Eliezer_Yudkowsky comments on No One Knows What Science Doesn't Know - Less Wrong

38 Post author: Eliezer_Yudkowsky 25 October 2007 11:47PM

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Comment author: Eliezer_Yudkowsky 11 February 2010 09:07:50PM 8 points [-]

Apparently the full quote from Richard Feynman is:

"I think I can safely say that nobody understands quantum mechanics."

This was in 1965. Everett's first paper was in 1957 IIRC. So not only was Feynman mistaken about nobody at that time understanding quantum mechanics, but he thought this could be said safely? When there are billions of people in the world, and all ignorance and confusion is a property of the map rather than the territory?

Feynman was one of the great Traditional Rationalists, but sometimes he really does manage to get it completely wrong. Einstein was much worse in the same department: "You do not really understand something unless you can explain it to your grandmother"!?

Comment author: Douglas_Knight 12 February 2010 05:37:42AM 8 points [-]

This was in 1965. Everett's first paper was in 1957 IIRC. So not only was Feynman mistaken about nobody at that time understanding quantum mechanics, but he thought this could be said safely?

Why are you so sure Feynman is ignorant of Everett, rather than talking about him?

I'd expect that Wheeler, who liked Everett's work enough to write a companion piece, would have told his other students about it. Steve Hsu points to a 1957 conference where Wheeler talked about Everett and Feynman made it clear he was interested in this stuff.

Comment author: Kutta 12 February 2010 12:23:09PM *  2 points [-]

I think it's likely that both quotes were unrepresentative passages or insignificant slips of tongue that only got magnified and entrenched in people's minds after years of memetic selection. It's obvious that Einstein couldn't have meant the grandmother quote seriously, also, Einstein is known to be very prone to rampant misquotation. The grandmother quote is quite comforting to the layman, even if untrue, and sounds "deep" enough, likewise the Feynman quote raises the status of confused non-physicists and physicists alike, because "not even the pros get it, and it's allowed to not get it."

Comment author: Tyrrell_McAllister 12 February 2010 08:52:45PM *  6 points [-]

"I think I can safely say that nobody understands quantum mechanics."

This was in 1965. Everett's first paper was in 1957 IIRC. So not only was Feynman mistaken about nobody at that time understanding quantum mechanics

So long as the key link between the QM formalism and empirical observations is a mystery, I think it's fair to say that no one understands QM completely. In context, is it too charitable to read Feynman as referring to still-outstanding mysteries such as that?

Comment author: ata 07 May 2010 05:31:56AM *  10 points [-]

Einstein was much worse in the same department: "You do not really understand something unless you can explain it to your grandmother"!?

That's probably a misquote, it turns out. I can't find any source for it and Wikiquote agrees. The closest they could find was Ronald W. Clark claiming that Louis de Broglie claimed that Einstein believed "that all physical theories, their mathematical expressions apart, ought to lend themselves to so simple a description 'that even a child could understand them.'" (I'm interpreting this to mean that Clark attributed the outer quote to de Broglie, who attributed the inner quote to Einstein while giving his own explanation of the context.) Could be true, but our knowledge of it is a few degrees away from the primary source, so there's room for it to get corrupted or taken out of context along the way. And even if it is correctly attributed and interpreted, the "their mathematical expressions apart" bit redeems it somewhat (not completely). Though that does dilute the meaning of "understand[ing]" as used, or it identifies it with (as you've termed them) verbal understanding rather than technical understanding.

I'm going to tentatively reject the belief that the "...unless you can explain it to your grandmother"/"that even a child could understand them" quotes accurately describe Einstein's belief. He may have been a Traditional Rationalist, but he wasn't stupid, and I imagine he had a great deal of experience explaining things as well as he could but not having everyone (let alone children or stereotypical grandmothers) understand him.

(And I'm going to give myself a rationalist experience point for finding the original "grandmother" quote surprising enough that I thought to look it up.)

Comment author: JoshuaZ 07 May 2010 05:46:03AM 0 points [-]

Hmm, so how many xp do you get per a level?

Comment author: byrnema 07 May 2010 12:57:31PM *  1 point [-]

"You do not really understand something unless you can explain it to your grandmother"!?

This was probably said by Feynman. I'm pretty sure because I have an auditory memory of him saying it in a video ... but I can't remember which one, and wonder if perhaps I read it after all in his Lectures.

Comment author: [deleted] 19 November 2011 08:18:52PM 2 points [-]

IIRC, in the Lectures he says “to a freshman” not “to your grandmother”. It allegedly was Einstein who said “to your grandmother” (and Rutherford said “to a bartender”, and [someone else] said “to [someone else]” and so on).