
Can Analogies Reveal the Laws of Physics? - rbanffy
http://nautil.us/blog/can-analogies-reveal-the-laws-of-physics
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JackFr
> Hartmann argues that experimenting on sonic black holes may indeed shed
> light on real ones because there might be a “common cause” underlying their
> similar mathematics. In the same way, yellow fingers and heart disease are
> both caused by smoking, and detecting one can be evidence of the other.

That seems like a terrible way to make this point. Honestly it practically
argues against it.

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whatshisface
Physical analogues occupy exactly the same epistemological status as numerical
models. Before computers were used, scientists used to build physical
analogues.

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tanderson92
This is not true. With numerical models one can quantify the level of error
one introduces and introduce a rigorous error analysis around the method.

~~~
whatshisface
You can also quantify the error introduced by physical models. For example,
figuring out the amplitude of the line noise on your bank of capacitors and
op-amps that are making up an analog computer. Electrical engineers know (and
knew) a great deal about noise in their analog systems.

Here are some cool analog computers:
[http://www.analogmuseum.org/english/impressions/](http://www.analogmuseum.org/english/impressions/)

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adrianN
>On the flip side, many black hole experts put no stock in the analogy and
consider it potentially misleading, since it isn’t known whether Hawking’s
math, upon which the analogy is based, actually does describe black holes.

That is the key issue. You can't do an experiment in a system X that can be
described by similar math as system Y and conclude things about Y without
first making sure that Y is actually behaving in the same way. These analogue
experiments might be good tools to explore the consequences of the mathematics
and come up with new theories, but in the end you only get results on system Y
under the condition that your theories about it are correct. That doesn't
sound too interesting, especially if you just confirm effects that you already
derived theoretically. In that case you already know that if they behave
according to your math then you'd see that effect.

~~~
blueprint
Does this not apply even to experimental result interpretation? e.g. One can
argue that the GRACE satellite program didn't image gravity, but showed the
theory and the effect of the theory.

~~~
adrianN
Sure, it has happened before that we found a different theory that's also
compatible with the experimental evidence.

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v_lisivka
Demonstrations of effects are playing important role in teaching, so analogies
may or may not reveal new laws of physics, but they certainly will inspire new
scientists.

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LeifCarrotson
This is especially important when we're talking about something as difficult
to observe, measure, and test as astronomical phenomena. Staring at

    
    
        F = G * m_1 * m_2 / r^2
    

may not provide an intuitive sense of what's happening for many students.

Many equations in physics are just not that complicated. A few constants, a
multiplication here, a division there, and a square or square root operation
describe most of the mathematics. If you can come up with a physical analogy
that operates on the same mathematics (like using electric charges and
Coulomb's Law - which matches the above equation - to simulate gravity), you
can do interesting tests on a workbench with some wires and charged spheres
where real world tests would be impractical. This is really cool and useful!

However, conveying understanding of an existing law that we already know isn't
the same as revealing new physics. Coulomb's law and Newton's law of universal
gravitation are the same; that's not to say you can hook up the electrical
charges in a Coulomb's Law demonstrator to an electric circuit and reveal
something that could be done with gravity.

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mitchtbaum
[https://plato.stanford.edu/entries/reasoning-
analogy/](https://plato.stanford.edu/entries/reasoning-analogy/)

[http://changingminds.org/disciplines/argument/types_reasonin...](http://changingminds.org/disciplines/argument/types_reasoning/analogical_reasoning.htm)

[https://en.wikipedia.org/wiki/As_above,_so_below](https://en.wikipedia.org/wiki/As_above,_so_below)

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arithma
This might be most interesting to tackle emergent behavior theories like
turbulence, where the fundamentals are known, but how they line up to cause an
effect is still a mystery.

