A good question
In the seventh Century BCE, Thales of Miletus was mystified by the mineral lodestone; capable of attracting iron from a distance and repelling other lodestones depending on orientation. Three centuries later, Shaggy 2 Dope of Insane Clown Posse highlighted Thales’ quandry in the song Miracles with the inspirational lyrics:
“Water, fire, air and dirt;
F***in magnets, how do they work?
And I don’t wanna talk to a Scientist,
Y’all motherf****rs lyin’ getting me p***ed.”
If you’ve not come across the horror-core, hip-hop band Insane Clown Posse I can save you a lot of trouble. This is them:
This isn’t the first time I’ve made jokes at the expense of ICP on my website and when they released Miracles the internet exploded with derision. One interviewer handed them a children’s Science book, while Saturday Night Live did a sketch where the Posse ask increasingly dumb and obvious questions. But, as it happens, I see their point.
Not only are magnets wierd, when Scientists try to explain them the answers never seem complete or clear. How does a magnet know when another magnet is close? How do they know which way the other magnet is facing and why does this alignment cause attraction or repulsion? How can a magnet “reach out” through empty space, sometimes through other objects, and influence another magnet at a distance?
These are good questions and consequently (this is a sentence I never thought I’d type as a self-respecting adult) I understand where Insane Clown Posse are coming from. How do magnets work and why does it seem like Scientists always lie about them?
As a teacher, I can probably explain the phenomenon of magnetism half a dozen ways but I have to be honest, Shaggy 2 Dope is correct: all of the explanations are cheating. They are pedagogical slight-of-hand tricks which don’t answer the question honestly. This can be frustrating for anyone wanting to learn and it’s just as frustrating for Science teachers.
We aren’t lying though, I promise you that Mr Dope. The problem with magnets is that there is no satisfactory explanation for how they work and I’m going to explain why. This question is going to take us right to the heart of what Scientific explanations really are. It’s going to get quite philosophical but hopefully it will shed some light on the very nature of what Science is capable of. So, magnets…how do they work?
Fantastic Mr Feynman
In a famous interview with Nobel Laureate Richard Feynman, Christopher Sykes asks the magnet question (link at the end). Feynman answers with a surprisingly bald sentence “What do you wanna know - the magnets repel each other.” Sykes starts to get frustrated because Feynman is merely stating what everyone already knows, but then Feynman points out that the difference between describing and explaining is often very slim.
Thing is, Richard Feynman was not just one of the world's greatest physicists, he was one of the greatest explainers of Science too. He had a knack for breaking complicated ideas into simpler statements, but on this instance he seems to be telling us very little. And this is really worth noting. If Richard Feynman can’t explain magnetism any simpler than stating what happens, can we really expect to do any better?
Fantastic Mr Faraday’s Fields
Probably the most important Scientist in the history of magnetic research was the equally legendary Michael Faraday. A few hundred years before Feynman took centre stage, it was Faraday who was the world’s most renowned Science populariser.
Unlike Feynman, Faraday had no formal schooling and didn’t feel comfortable with mathematics, but they shared a desire to understand the world in the simplest terms possible. They were both from the school of “if you can’t say it simply you don’t understand it” and Faraday had an elegant way of dealing with magnetism - by introducing the concept of a field.
Magnets clearly have the ability to create environments around them which influence similar environments. These environments can act through solid objects, so they are not made of magnetic particles and they also aren’t disturbances in the geometry of empty space, because only certain objects are affected.
Faraday began visualising these environments of influence as lines spreading from the object, with arrows showing the direction in which the influence pointed. The shape of a magnet’s influence-environment can be measured precisely and we refer to it as the magnet’s field, illustrated below.
Fields are typically what Science teachers use to explain magnetism. We say a magnet creates a field around it with a distinct shape, or sometimes we talk about the Universe having a magnetic field and magnets distorting it. When two magnets are facing top to tail the lines of the field are pointing in the same direction and they reinforce. If you flip them, the field arrows are pointing in opposition and the magnets separate.
This sounds like a solid explanation but it hasn’t told us anything we didn’t already know. The question “how do magnets influence other magnetic things in the environment” has been answered by saying “magnets create an environment which infleunces other magnetic things.” We’ve answered the question by re-stating it.
Faraday’s field-lines are useful as a description of where the field is but they don't tell us what the field is. I mean, what’s it made of? What specificaly is pointing in a certain direction? Why does having the fields aligned cause attractions and repulsions at all? In other words…magnets, how do they work?
Down to the wire
Perhaps a different way of asking the question might get us closer to an answer which feels right: why are some things magnetic but not others? Only a few substances are magnetic on their own (Iron, Cobalt, Nickel, Gadolinium and Terbium) but any metal can be forced to magnetism by passing a current through it. What clue does that give us? Well, what makes these metals special is that their electrons are arranged in specific ways. Electricity is also about electrons, so maybe electrons themselves are magnetic?
It turns out that this is correct; electrons have a tiny magnetic field surrounding them. When they are stacked up with fields aligned (as they do in metals like Iron or in electric wires) the result is a giant field. Other metals don’t arrange their electrons the same way so they aren’t magnetic.
Magnetism seems to come from something electrons are doing and their field-strength has even been pinned down to three properties, related by the following equation:
This tells us that any particle which has mass, electric charge and some property named S (which stands for something I don’t want to get into) will be magnetic. When we investigate other particles which have mass, charge and S, we find they are also magnetic so the equation is obviously accurate. But it hasn’t told us what the magnetic field is.
The first problem is charge. Mass is a very easy property to explain but charge is not. Electrons repel each other and attract protons, similar to magnetic behaviour, but what makes this happen? We can describe electrons and protons as having electric-charge fields but this is the same cheat we’ve used before. It’s just describing what they do, not how they do it.
I need to point out that we actually do have a pretty good understanding of what causes an electron to have a charge, but asking how this causes interactions with other particles is the magnetic field question all over again. (NB: some people might be thinking the answer is to do with photons, but this only rephrases the question into: why do electrons cause photon behaviours around them? It’s a red herring).
The other problem is the property S. We roughly know what charge is, but we don't have a clue what causes a particle to have S. It’s something quantum mechanical and therefore beyond our intuition. The only way we know this property exists is because an experiment was carried out to detect it...which consisted of firing electrons between mangets. The experiment showed that there is a particle property distinct from electric charge and it has something to do with magnetism but this doesn’t add new information. It’s saying “magnetic particles have a property which responds to magnetic influence”. Well…duh.
We’re back to square one. Magnets are magnetic because electrons are magnetic. They are magnetic because they have properties which cause magnetism. The above equation and the field lines are describing what the phenomenon is going to be like, which is of great use (every electrical device in the world works because we’ve learned to control magnetic and electric fields) but they are just descriptions of a phenomenon which don't tell us how the phenomenon arises. Feynman’s answer is still the best.
Still you Shaggy. Very much still you.
I feel it in my fingers, I feel it in my toes. Magnets all around me, and so the feeling grows
While answering Christopher Sykes, Feynman points out that magnetism doesn’t spook us when we experience it in other contexts. Right now you’re sitting on a chair and think of yourself as being in contact with it. But you aren’t. The electrons in you and the electrons in the chair are repelling electrically and magnetically (the two are closely linked, so for simplicity I’m going to describe them as one thing).
If you were to zoom in, you would see that both sets of electrons have magnetic fields which push against each other and allow the surfaces to repel rather than merge. The very act of touching an object is basically magnetic repulsion, it’s just that the gap between the particles is too small to see. Quantum mechanically, particle repulsions happen all the time but we aren't used to seeing quantum behaviour at the everyday level.
That's what makes magnets hard to understand. They are a quantum process being studied by classical human brains and when you have a phenomenon which the human brain can’t understand you can only describe it, not explain it. “What do you wanna know? - the magnets repel each other.”
Be positive and get real
The philosopher Ludwig Wittgenstein once said “at the basis of the whole modern view of the world lies the illusion that the so called laws of nature are explanations of natural phenomena.” He was saying that laws of nature are merely descriptions rather than explanations.
On another occasion he said “man has awoken to wonder…Science is a way of sending him to sleep again,” and he also criticised Science for “reducing the explanation of natural phenomena to the smallest number of primitive natural laws.” Wittgenstein was undoubtedly a philosophical genius but I have to be honest, he was a grumpy git.
The two positions which arose from his influence on early 20th century philosophy are called realism and positivism. Realism says that Science explains the world. Positivism says Science is only keeping track of what happens and has no explanatory power.
According to positivists like Wittgenstein and Shaggy 2 Dope, all we are doing as Scientists is saying that a particular thing happens and then saying "the thing which makes it happen is what makes it happen.” We might give it a name or measure it mathematically but it's not a true explanation.
I think this is an unfair criticism and a semantically obscure one. After all, we could dismiss philosophical statements by saying “the answer to any question is whatever answers it.” If you decide the answer to every “why?” is simply “because” then you might as well ask what the point in questions is. The answer is just whatever the answer is. Science can do something far greater than just describing what we already know.
Hitting Rock Bottom
I remember asking my Physics and Chemistry teachers why molecules had certain shapes. The answer was that atoms themselves had the shapes and they dictated the angles. So I asked why atoms had these shapes. The answer was that electrons moved in a particular way which arose from their charge being opposite to a proton’s. So I asked why electrons and protons had opposite charges. The answer was “that’s the way things are.” And then I got frustrated.
It seemed defeatist. Although I don’t know what I expected. If you take any phenomenon and keep asking “why?” you will eventually hit the bottom of the ladder and be faced with “that’s the way things are”.
Let’s say we discovered electrons have tiny harpoons firing out of them on one side, creating magnetic attractions in one direction. That would feel like a proper explanation until someone thought to ask “well why do they have harpoons in the first place?”
Every time we uncover a mechanism we are generating a question…why is it like that? Even if Science arrives at a single theory which explains everything in the Universe we could sill ask “why is that theory true?”
In a sense, this means we can never really explain anything because every answer is resting on a deep-down truth that the Universe just is a certain way. But I think that’s a ludicrously pessimistic approach. There is every reason to try and answer questions about the world because I think there is a subtle difference between explanation and description.
Describe vs Explain
Let’s take one of the most common questions I get asked as a teacher: why do we dream? If we follow it through with the eternal “why” question we eventually get to the limit of ignorance:
Q: Why do we dream?
A: Because the outer layers of the brain shut down and the inner layers, full of crazy thoughts, take over.
A: Because the brain has to conserve energy.
A: Because there is a limited supply of it.
A: Because food contains a specific amount.
A: Because food gets its energy from the Sun and the Sun only generates a certain amount.
A: Because the Sun gets its energy from the limited number of particles inside it.
A: Because particles smashing together at high speed gives out energy.
A: Because movement and energy are closely related by Einstein’s theory of special relativity.
A: Because that’s just the way it is.
The answers to the above questions are what I think we mean by “explanation”. As we answer the question we are re-describing accepted knowledge but in a way that adds information. An explanation is therefore the steps between the original question and the final “that’s the way it is” statement. So a teacher's job is clear: describe all the steps by adding information until the person asking is satisfied.
This is really what makes magnets difficult to explain. The gap between “how do they work?” and “that’s the way they are,” is very small. That’s the point Feynman was making. The magnets repel each other and there is no deeper level, that’s already it. We’ve hit the boundary of wierd quantum stuff and there isn’t anything we can say to add to the description.
As I’ve said, the final question will always be: why is it like that? But what that question refers to will keep changing. We start by asking “why is A like that?” and get the answer “because B is true.” Then we’ll ask “why is B like that?” and get the answer “because C is true” and so on. The question will always get asked and the answer will always give rise to another question. Maybe one day we will have an answer to every question but it will be too weird to know what the next question to ask is. To me this is exciting because it means Science will never run out of things to investigate and it will never know everything.
So what’s the point?
Explanations are just descriptions with extra information and right at the bottom of every explanation we have a big fat question mark. Science can’t answer the fundmanetal “why is the world like that?” so Wittgenstein would query what the point of Science is full stop. I think the answer should be obvious.
Earlier, when we answered where dreams come from we ended up at special relativity, but there are many other questions which would take us to the same point. If you asked me why light moves the way it does (nothing to do with dreams) we would end up at special relativity. If you asked me how a nuclear bomb works, we would end up at special relativity. And so on.
Special relativity is a "law of nature" which means it is a fact we use to explain other things, not the other way around. It's one of the axioms we have to accept until someone goes a level deeper. This is what scientific discovery is about, trying to go as far down the ladder as possible until we have a bunch of statements which we can't add information to - we just say what they are.
When Isaac Newton discovered gravity, he was recognising that the descriptions we use for planets and stars can be used for objects moving on Earth. He unified two separate realms with a single principle. Michael Faraday discovered that the descriptions we use for electric properties can be used for magnetism too. Steven Weinberg, Abdus Salam and Sheldon Glashow were then able to unite Faraday’s electromagnetic laws with radioactivity and it keeps going.
When we uncover a Scientific “law” we are describing a link between apparently separate events or processes. It’s phrasing one thing in terms of something else and this is what Wittgenstein hated. Generalisations were to be avoided in his world view because there was no reason to assume separate events were linked by anything other than coincidence.
Perhaps tomorrow half the electrons in the Universe will decide to flip charge for no reason. Maybe gravity will vanish altogether. I can't prove this won't happen. But we don't live our lives assuming the Universe is illogical and generalisaitons work by accident. We assume we live on the inside wall of a logically bound Universe and go from there. When you wake up, you don't know for certain that the floor will be there when you put your foot down, but you do it anyway.
The tree metaphor
I imagine special relativity like a branch on a tree with observable phenomena being the twigs and twiglets which sprout off it. When we ask a question about the world we’re starting at some point on the outside of the tree and every successive question works inward toward bigger and more general answers.
At the moment, Science is built on a few main boughs of this imaginary tree and we haven’t yet unified them into a single trunk. But when we have done so, that trunk will extend down as far as we can go, maybe even connecting to other Universes with different laws.
Magnetism is one branch on this tree of knowledge. We can observe its effects and we want a deeper explantion but that’s because we’re used to starting out on the twigs. Magnetism is already one of the principles which explains other things, not the other way around. We may discover a magnetic mechanism one day and that would be fantastic, but the next generation of hip-hop clown rappers would simply ask “the magnetic mechanism - how does that work?”
The point is that the more links we discover, the more we can make a difference to the world. You’re reading this on a computer screen based on laws of electricity which…deep down…are based on mystery. You wear clothes and live in buildings made from chemicals that are based on laws which...deep down…are based on mystery.
The medicines you take, the books you read and everything else that makes life grand are all based on things we can't comprehend, but that doesn't mean we should stop asking questions about things we can comprehend. We’ve tasted fruit from the tree of knowledge and it has undoubtedly made the world a better place. I see no reason to stop eating.
I have now, hopefully, explained how magnets work, why the question is difficult to answer, what the philosophy of scientific explanation is, what the job of teaching is and managed to quote Richard Feynman, Ludwig Wittgenstein and Insane Clown Posse in one blog. And now, I'll leave you with the master...
I love science, let me tell you why.