I've never really been that impressed with Feynman's responses in that interview. He seems to be uncomfortable with just saying that physicists don't really know on a fundamental level why magnets repel each other. Obviously, explanations can be more or less fundamental.
He's trying to get the point across that "X don't really know on a fundamental level why X" for any group of people X and observation Y, if by "on a fundamental level" you mean "is not based on something assumed to be true". He's not uncomfortable with it, anyone with a scientific or engineering background knows that (or at least should know that). That doesn't stop predictions obtained from well-tested models from being useful.
Well, maybe that's what he's trying to get across, but it seems largely irrelevant to the interviewer's question. He could just have given a physics textbook level explanation of how magnets work. I'm not convinced that there's some kind of profound misunderstanding evident in the interviewer's question that needs addressing in long and rambling terms.
There is actually a subtle point on why the question of "physicists don't really know on a fundamental level why magnets repel each other" is nonsense ultimately which doesn't stop physics from producing useful or interesting in some other way models.
Those who think that a textbook explanation could have been the answer are missing the point: it is not about magnets—it is about what it means to know anything in terms of anything else.
There is no need for useful models to form a nested hierarchy converging to a single "reality" i.e., it is not necessary for a model to be more fundamental than another model even if they relate to what we observe as the same phenomenon.
What physics textbooks say about magnetic attraction is very far from being "trivially" true. It's a wealth of utterly non-obvious information resulting from centuries of scientific research.
Also, "cucumbers" is not an answer to the question you posed.
So you are telling me, you know the answer to my own question better then its author :)
I'm curious why do you think magnets repel? What terms would you use to describe it? How these terms are defined? What terms in turn are used in these definitions? How these terms are defined in turn? etc.
I love this interview it’s typical of Feynman; what do you mean by how magnet works is a fair question but it’s also a multi form one. We don’t really know we just know up to a certain level he had a lecture about how Mayans predicted astronomical events with beans, were the bean the answer to why?. I’ve learned a lot from this interview on how to look at science. Why is indeed a profound concept
"Interviewer: If you get hold of two magnets, and you push them, you can feel this pushing between them. Turn them around the other way, and they slam together. <q1> Now, what is it, the feeling between those two magnets? </q1>
Feynman: What do you mean, "What's the feeling between the two magnets?"
Interviewer: <q2> There's something there, isn't there? </q2> The sensation is that there's something there when you push these two magnets together.
Feynman: Listen to my question. What is the meaning when you say that there's a feeling? Of course you feel it. Now what do you want to know?
Interviewer: What I want to know is <q3>what's going on between these two bits of metal </q3>?
Feynman: They repel each other.
Interviewer: <q4> What does that mean, or why are they doing that, or how are they doing that? </q4> I think that's a perfectly reasonable question.
Feynman: Of course, it's an excellent question. But the problem, you see, when you ask why something happens, how does a person answer why something happens? For example, Aunt Minnie is in the hospital. Why? Because she went out, slipped on the ice, and broke her hip. That satisfies people. It satisfies, but it wouldn't satisfy someone who came from another planet and who knew nothing about why when you break your hip do you go to the hospital. How do you get to the hospital when the hip is broken? Well, because her husband, seeing that her hip was broken, called the hospital up and sent somebody to get her. All that is understood by people. And when you explain a why, you have to be in some framework that you allow something to be true. Otherwise, you're perpetually asking why."
I think Feynman properly responded to the questions asked -- people do thing that they have to "find a meaning" and "why" and talk about "the feeling."
Feynman properly answers there "of course you feel it!"
Follow very carefully his whole response (I link the transcript) -- it's deeply thought through and applicable to much more than just "feeling -- meaning -- why -- magnets." It's about the "why questions" and "meaning" questions in general, from the view of physics.
>But "how" was not a starting question of the interviewer
As your transcript shows, the interviewer asks "why are they doing that, or how are they doing that?".
That seems like it would have been a good point to respond with an explanation of why magnets repel each other.
I don't buy all this stuff about 'how' vs. 'why' questions anyway. Lots of 'why' questions are perfectly sensible scientific questions. E.g., 'Why don't magnets stick to aluminum?'
Exactly, and that "why" is answered thoroughly, see the transcript.
The part of "how" is also there:
"If you're somebody who doesn't know anything at all about it, all I can say is the magnetic force makes them repel, and that you're feeling that force.
You say, "That's very strange, because I don't feel kind of force like that in other circumstances." When you turn them the other way, they attract. There's a very analogous force, electrical force, which is the same kind of a question, that's also very weird. But you're not at all disturbed by the fact that when you put your hand on a chair, it pushes you back. But we found out by looking at it that that's the same force, as a matter of fact (an electrical force, not magnetic exactly, in that case). But it's the same electric repulsions that are involved in keeping your finger away from the chair because it's electrical forces in minor and microscopic details. There's other forces involved, connected to electrical forces. It turns out that the magnetic and electrical force with which I wish to explain this repulsion in the first place is what ultimately is the deeper thing that we have to start with to explain many other things that everybody would just accept. You know you can't put your hand through the chair; that's taken for granted. But that you can't put your hand through the chair, when looked at more closely, why, involves the same repulsive forces that appear in magnets. The situation you then have to explain is why, in magnets, it goes over a bigger distance than ordinarily. There it has to do with the fact that in iron all the electrons are spinning in the same direction, they all get lined up, and they magnify the effect of the force 'til it's large enough, at a distance, that you can feel it. But it's a force which is present all the time and very common and is a basic force of almost - I mean, I could go a little further back if I went more technical - but on an early level I've just got to tell you that's going to be one of the things you'll just have to take as an element of the world: the existence of magnetic repulsion, or electrical attraction, magnetic attraction.
I can't explain that attraction in terms of anything else that's familiar to you. For example, if we said the magnets attract like if rubber bands, I would be cheating you. Because they're not connected by rubber bands. I'd soon be in trouble. And secondly, if you were curious enough, you'd ask me why rubber bands tend to pull back together again, and I would end up explaining that in terms of electrical forces, which are the very things that I'm trying to use the rubber bands to explain. So I have cheated very badly, you see. So I am not going to be able to give you an answer to why magnets attract each other except to tell you that they do. And to tell you that that's one of the elements in the world - there are electrical forces, magnetic forces, gravitational forces, and others, and those are some of the parts. If you were a student, I could go further. I could tell you that the magnetic forces are related to the electrical forces very intimately, that the relationship between the gravity forces and electrical forces remains unknown, and so on. But I really can't do a good job, any job, of explaining magnetic force in terms of something else you're more familiar with, because I don't understand it in terms of anything else that you're more familiar with."
Yeah, he answers the question. I just think people are giving Feynman too much credit here. He seems to have been in a grumpy gramps mood that day and taken some time to actually get round to answering the question.
No -- he used the question to demonstrate the basic premises of physics -- that the "whys" can never end, as long as somebody is not "satisfied" with the answer, and that to even understand "how" needs some precondition to be useful in any way to the one who asked, and that otherwise it's just "cheating" or practically giving somebody false sense that he'll know something because the analogies popularly used are just wrong.
Like he said, the bigger marvel is that, that the same electromagnetic forces are what keeps us from falling through the floor. Or what keeps the apple hanging on the tree.
Or, only specific to the human uses, how the movement of water is transformed to supply remotely the electrical machines with the power.
But that's what nobody asks, because they don't "feel" it unusual. The magnets are just a small manifestation of the same forces that "feels" unusual to the people.
It's his answers to "philosophers" who earn the points asking "whys" which, from his point of view, are too wrong to ask, having a false context.
Everyone understands that you can keep asking "why?". Four year old kids understand this.
What the interviewer obviously wanted was an explanation of a particular physical phenomenon targeted at the level of someone without any background in physics. Everyone, Feynman included, has been in that position.
> What the interviewer obviously wanted was an explanation of a particular physical phenomenon targeted at the level of someone without any background in physics.
How do you know that? I would claim that it's what you expected and even if you received that (as quoted before!) you double down on showing the dissatisfaction in what preceded that explanation, namely, Feynman explaining that the "satisfaction" impression of every answer depends on the already existing knowledge of the person who asks.
But the answer was completely honest: there aren't any intuitions about electromagnetic fields present in someone "without any background in physics" which would allow the decent (non-cheating) answer.
I actually think his explanation is right on. Physicists are practical. They make model to quantitatively describe their experiments. Understanding fundamental truth is kind of a by-product.
They generally follows a reductionist approach, so a simpler model that can explain a wider set of experiments is a better model. But there's no guarantee that a simpler explanation is the "truth". All we can say is this approach "makes sense".
> Obviously, explanations can be more or less fundamental.
That's not obvious, in fact, it's not even true. Feynman's point is that people bring context to a question. People will accept different things as 'fundamental'; different assumptions and axioms. Can you sometimes explain things using fewer axioms? Sometimes; but is it more fundamental? Is it better to build a theory on fewer axioms, even if they can't be directly validated? Would you prefer a theory based on 4 axioms, none of which can be directly validated, over one with 6, but you can measure all six directly? What if the four can't be re-derived from the 6, but all observable statements can? What if either set can be re-derived from the other?
Feynman isn't saying that "physicists don't really know on a fundamental level why magnets repel each other". He's alluding to the idea that that question isn't well defined. He's encouraging the questioner to figure out what sort of answer would satisfy them, and why.
I think it's obviously true that some explanations are more fundamental than others. We have, e.g. a more fundamental explanation of tides than anyone did in 500AD. That is not to deny that it is difficult to make precise what exactly it is that makes one explanation more 'fundamental' than another. As always, individual cases are clear; the general principle is elusive.
>He's alluding to the idea that that question isn't well defined.
It's well-defined enough to answer. Hundreds of millions of school children learn a perfectly sensible answer to the question every year. (Would this answer satisfy someone with a PhD in physics? Obviously not. But that's not the point.)
It's in any case bizarre to insist that a layperson ask a question that's well-defined according to the standards of a particular field.
The odd thing is, we physicists actually have a pretty solid understanding of why magnets repel each other. It's a fun story, one that I try to include every time I teach the subject, and I'm pretty sure that Feynman knew it! So it's curious to me to see Feynman basically dodging this question. (His point that "I can't explain it in terms of anything else you're already familiar with" is entirely valid! But I kinda feel like that's what questions are for: learning new things, that we may not already be familiar with.)
With that in mind, I probably would have answered in a different way, though the questioner might get bored and regret asking if I didn't find a way to be unusually efficient about it: this answer relies on a lot of knowledge that seems at best tangentially related. :) I'd try to give some rough description of the way that moving currents generate magnetic fields (especially the field generated by a current loop), and the way that moving currents feel a force due to magnetic fields (especially the force on a current loop). That's enough to argue that current loops will interact with each other in just the same ways that magnets do. And then I could tell at least a sketch of the story of how regions of aligned spins in magnetic materials act on average like current loops. (But that's quite a long story to answer a simple question, so again, I can sympathize with Feynman for saying, "There isn't a straightforward answer that a non-expert would understand.")
Didn’t his answer boil down to “The math is the physics. That’s the explanation. That’s how it works. You can’t just make up an analogy because the math is the analogy”
That seems a bit extreme and not really consistent with the attitude he took in his public lectures and in Surely You're Joking. It amounts to giving up and saying that you can't explain basic physical phenomena to laypeople on any level.
