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Comment by DanBC | Hacker News Reader

For various values of "we".

http://www.grc.nasa.gov/WWW/K-12/airplane/lift1.html

> There are many explanations for the generation of lift found in encyclopedias, in basic physics textbooks, and on Web sites. Unfortunately, many of the explanations are misleading and incorrect. Theories on the generation of lift have become a source of great controversy and a topic for heated arguments.

There are lots of bits of science where we have "useful lies" used to explain things to people, but when you get more in depth things get trickier.

Clifford Stoll uses the question "Why is the sky blue?" as an example. You keep asking "Why?" as a response and see how far someone goes. Most people will say "light scatters"; some might say "Rayleigh scattering".

Of course, there is a difference between "Science knows but the general population hasn't learnt it" and "science doesn't know" but for a surprising amount of stuff science doesn't know, yet.

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By "we", I mean humanity as a whole. Nobody would contest that there are a lot of widespread misconceptions about how an airplane - or, for that matter, anything - works.

A nice blog post on the topic is Sean Carroll's article, "The Laws Underlying The Physics of Everyday Life Are Completely Understood" (http://blogs.discovermagazine.com/cosmicvariance/2010/09/23/...).

https://www.youtube.com/watch?v=MO0r930Sn_8

Feynman: "Magnets repel each other."

Interviewer: "What I want to know is what's going on ..."

Feynman: "Magnets repel each other."

Interviewer: "...between those two bits of metal."

Feynman: "Magnets repel each other."

Interviewer: "Well then, but what does that mean? Or why are they doing that? Or how are they doing it?"

Feynman: "Ah, [pause] uh you're asking ..."

Interviewer: "I must say that's a perfectly reasonable question to ask"

Feynman: "Of course! It's a perfectly reasonable question."

See also his quote about quantum mechanics - "There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time. There might have been a time when only one man did, because he was the only guy who caught on, before he wrote his paper. But after people read the paper a lot of people understood the theory of relativity in some way or other, certainly more than twelve. On the other hand, I think I can safely say that nobody understands quantum mechanics."

https://en.wikiquote.org/wiki/Talk:Richard_Feynman#.22If_you...

One of the problems with this idea, that we have the physics "perfectly understood", is that even that statement isn't accurate. What we actually have are unbelievably precise models for how things work and people who understand those models at extremely deep levels.

But even something we experience literally every moment of every day, like gravity or magnets, we haven't the foggiest idea of how it actually works. We can describe in great depth anything we wish about our models for these things and experiments can reproduce our theories with exquisite precision.

But these models are merely complex rituals, we don't actually know, at a deep fundamental level, what happens.

The Feynman answer to magnetism, for example, is deeply unsatisfying because he describes all the rituals we've discovered with science about magnetism, but never really answers the question. His answer, in 7.5 minutes are "all the electronics spin in the same direction in iron and that produces a magnified magnetic field large enough we can feel". But why do spinning electrons produce a magnetic field at all? And why does that field work the way it does?

We have built beautiful mathematical tools to describe this force, down to elementary particles, but why it exists at all is a completely mystery.

All models are wrong. Some are useful.

But what is your point, really?

By "understand" in physics, we really mean that we can predict what will happen in a given experiment to any desired accuracy based on the established "laws of physics".

"But even something we experience literally every moment of every day, like gravity or magnets, we haven't the foggiest idea of how it actually works."

I think this does a deep disservice to how much we actually do know about how the universe works.

My point is that people often confuse understanding the model with understanding the thing. The model becomes a ritual, it becomes a kind of complex dogma, and when people master the model they claim they understand it. But it's not true, they don't understand the thing, they only understand our description of it.

Feynman also addresses this, https://www.youtube.com/watch?v=05WS0WN7zMQ

The next Monday, when the fathers were all back at work, we kids were playing in a field. One kid says to me, “See that bird? What kind of bird is that?” I said, “I haven’t the slightest idea what kind of a bird it is.” He says, “It’s a brown-throated thrush. Your father doesn’t teach you anything!” But it was the opposite. He had already taught me: “See that bird?” he says. “It’s a Spencer’s warbler.” (I knew he didn’t know the real name.) “Well, in Italian, it’s a Chutto Lapittida. In Portuguese, it’s a Bom da Peida. In Chinese, it’s a Chung-long-tah, and in Japanese, it’s a Katano Tekeda. You can know the name of that bird in all the languages of the world, but when you’re finished, you’ll know absolutely nothing whatever about the bird. You’ll only know about humans in different places, and what they call the bird. So let’s look at the bird and see what it’s doing—that’s what counts.” (I learned very early the difference between knowing the name of something and knowing something.)

Models are just a complicated way of calling something, not a way of understanding it. Getting experimental results just means you've used the correct name, not that you understand anything in particular about it.

Calling a hot bright thing "fire" doesn't mean you understand it at all -- no matter how many complex tribal dances you do around an open flame. Knowing what fire actually is gave us modern civilization. For many fundamental everyday things like gravity or magnetism, on the scale from "calling an open flame 'fire'" to "rocket ship", we're charitably somewhere around "learning to cook meat".

> I think this does a deep disservice to how much we actually do know about how the universe works.

No! It just means that we know vast amounts about the Universe, but we still have more to learn.

One of the problems with your argument is, as usual in these kinds of discussions, enthymematic: much lies in your particular notions of "explanation" and "understanding", which to you seem to self-evidently involve far from than their usual lexical sense --eg to many, Feynman's explanation of magnetism, with its remarkable succinctness, granularity and predictive power, is quite sound and satisfying!

So I would suggest you to begin by explicitly defining [1] what your particular notion of "understanding" is, so that you can then clarify what exactly is it that you find unsatisfying about modern physical law.

[1] http://www.philosophypages.com/lg/e05.htm

Okay, yeah sure. Good point. If you want to get down into those kinds of philosophical details, I'm not sure I'm prepared to do that. Right now, I'm kind of like the Supreme Court on pornography, I recognize understanding when I see it.

I think Feynman handles the question incorrectly. The question is about his understanding of magnetism, but he places the burden on the receiver of the explanation. If they don't understand the explanation then it doesn't matter. I do get his point in this and I'm not entirely saying it's wrong. But I think also that it's a deflection.

Lets assume a "presently omniscient" listener asking the question, somebody who may not have the knowledge before it is presented to them, but will understand the explanation perfectly as it's provided.

Suppose a Feynman or some other physicist has such a listener and they go on a deep dive into all the myriad and intricate details, the sum of all human knowledge on the matter -- this kind of listener would be able to follow along entirely with every last detail.

This listener would still not have an answer to the question "how do magnets work?" Because science doesn't actually know the answer to this. We have excellent descriptions of what magnets do, and what produces magnetism. We can predict to some nth decimal point of precision the outcome of just about any given experiment such that we don't really bother much with experimental physics about most of the day-to-day magnetism.

But why do those things produce magnetism at all?

The answers to this is basically "it just does". And that's as good as all our knowledge is. That's all we've arrived at. For all we know, every time an electron starts circling something, invisible universe fairies produce "magnetism" magic that does what we observe.

We don't know why magnetism does what it does, only that it does it.

But imagine if we actually understood it, at a fundamental level, if we "groked" magnetism and were the masters of it...

https://news.ycombinator.com/item?id=8148377

One can go further still and differentiate between "science has a reasonably accurate model" and "science has a standard way of describing and characterizing an effect."

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