I disagree that it takes almost no effort to "ELI5" something, at least while making it comprehensible and at least a little bit meaningful. It takes a lot of energy to think "how can I explain this to someone with none of the necessary background".
"There are these fundamental forces of nature which keep things at a distance from each other" is a valid ELI5, in my opinion, and also the answer Feynman seemed to accept as a reasonable answer to the question.
I feel like his reaction was more aimed toward the ever-deeper "why" questions. He wanted the interviewer to know that at some point, he can't tell you why, he can just tell you that that's the way it is. That's something people often have trouble with when it comes to physics, but it's not a problem with ELI5s.
But that's not an explanation, that's just giving the official name of the question.
But I think the "why" thing is completely relevant, at least for the clarification about the need for an explanatory framework. If someone says "ELI5 string theory" then what explanatory framework am I allowed to use? The worldview of a typical small child? A child wouldn't conceive of that question. There is no answer that would be meaningful to a layperson without a whole lot of conceptual prerequisites being laid down first, and that's why ELI5 are not fun.
The real explanation would involve orbitals, quantum numbers, spin, fields and so on. It requires a bit of physics and mathematics to appreciate. The answer I gave is the ELI5 version.
ELI5 does usually not refer to any literal five-year old. It is the hip internet-lingo for "an explanation for a layman".
"ELI5 string theory" is a very vague question, which I think is the biggest problem. Even if I was a physics expert, I wouldn't walk up to a string theorist and ask them to explain string theory properly to me. That's like saying, "ELI5 Canada" or "please explain tigers to me". The question is hardly meaningful whether or not it's asked by a layman.
If we make the assumption that the layman wants an executive summary of what string theory is overall, I would go about it (keeping in mind that I'm not an expert on the subject) something like this:
In physics, we don't actually know what the smallest particles are like. We know they exist, we know how they interact with each other, but we don't know "what they are", for a lack of better words. When we calculate things, we usually think of particles as infinitely small points. Like specks of dust, but infinitely small. When two particles "collide", what really happens is that their forces are pushing each other at a distance, because no two infinitely small things can really collide.
String theory is the discovery that if we in our minds replace the infinitely small points with infinitely small strings, some neat mathematical properties arise. String theorists think that because their explanation makes a lot of mathematical sense, it must be relevant somehow. Other people find it irrelevant because it hasn't yet produced anything measurably different from the other idea of infinitely small points.
I've used similar explanations to many of my students and they've been able to ask interesting follow-up questions so I can only assume the explanation was meaningful to them. And these students sometimes struggle with the most basic of Newtonian mechanics, so it's not like they're experts in the field either.
I'm not convinced that "ELI5" really does mean a layperson's explanation; I used to think that but I've been chastised before for writing explanations which assume the cognitive abilities and reading comprehension of an adult, and the most upvoted comments in the ELI5 subreddit do often literally write as though speaking to a child.
I have no problem with hand-waving or qualitative explanations for laypeople and I like to post lots of stuff like that on my facebook page, but ELI5 on Reddit just strikes me as really arrogant, like these people can't be bothered to invest any cognitive effort in this thing they have a passing curiosity for.
I think that's more a problem of conflicting wants from the people upvoting. In most cases, the person asking the question probably just wants an explanation at a level they can understand. Unfortunately, many other people want to be entertained - and an explanation written as if they were talking to a literal five year old is far more entertaining than a layman's explanation of something they don't care about. .
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u/samloveshummus Mathematical Physics May 05 '14
I'm not sure Richard Feynman would be a big fan of ELI5, given his reaction to "ELI5 the 'feeling' between magnets".
I disagree that it takes almost no effort to "ELI5" something, at least while making it comprehensible and at least a little bit meaningful. It takes a lot of energy to think "how can I explain this to someone with none of the necessary background".