

Were atoms real? (Interesting discussion of scientific philosophy.) - yummyfajitas
http://lesswrong.com/lw/38z/were_atoms_real/

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lmkg
I think you can take this one step further and talk about models that are
actually false, but nonetheless work. Perhaps the best example would be
calculus, which treats space as continuous, and in that sense is the polar
opposite of the model of atoms. We now know that space is discretized (at the
Plank-length scale, ~10^-36ish meters), but calculus nonetheless remains a
remarkably effective and efficient model for making testable and verifiable
predictions about mechanics (which itself is false but useful). So calculus is
an example of the sort of "pedagogical device" that the 1860's philosophers
were debating.

The takeaway from this is that models need not be based firmly in reality to
be useful, and conversely that models that are useful and make correct
predictions may still nonetheless be based on false descriptions. My favorite
example of the latter is Lorentz transforms, which the author alluded to in
the article. The math behind changing frames of reference in special
relativity predates relativity itself, and were actually developed as a
mathematical model of the now-defunct theory of "ether," the posited medium
that light waves must move through and which happened to magically distort
space with some sort of drag force. Despite the fact that its theoretical
bases was completely false, Lorentz' (Lorentz's?) work nonetheless was an
accurate model, and could be translated whole into a totally different
theoretical framework.

Whether that new theoretical framework is accurate (i.e. "real") or not is
hard to tell. It seems to be holding up to advanced scrutiny so far, but
that's not a sure indicator.

~~~
alphaBetaGamma
The world is flat.

False, but true enough when you are building a bridge.

~~~
arethuza
Actually, I think very large bridges do need to account for the curvature of
the earth. For example:

<http://en.wikipedia.org/wiki/Vasco_da_Gama_Bridge>

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grovulent
As someone who has spent the last 5 years doing a phd in metaphilosophy and
metaphysics... please just trust me when I say:

Don't read this article... don't think about the question... Don't go near it!

I can't remember exactly why though. However, I did see admiral ackbar around
here somewhere - I think he knows.

~~~
pjscott
This article kind of _is_ a trap, actually. Check out the last paragraph:

> It seems that one disguised empirical question scientists are asking, when
> they ask “Is X real, or just a handy predictive device?” is the question:
> “will I still get accurate predictions, when I use X in a less circumscribed
> or compartmentalized manner?” (E.g., “will I get accurate predictions, when
> I use atoms to predict quantized charge on tiny oil drops, instead of using
> atoms only to predict the ratios in which macroscopic quantities combine?".

Rather than trying to answer the question, the author turns it into a slightly
different one that's easier to answer, and potentially more useful.

~~~
grovulent
Yeah theorists have been doing this since Plato. They can't understand the
question they've asked so they try to re-parse it into one that they can.

I'm not sure why - but it rarely occurs to them to just stop asking the first
question, and stop asking whether the second actually has the same semantic
content as the first. When I point this out to them they retort that I have no
rational argument that could reasonably compel them to accept that these
questions can't be answered. I accept the truth of this retort. However, I
offer them the prediction that animals that tend toward behaviours such as
theirs will get selected out of existence a whole lot sooner than those that
don't. It's a purely empirical hypothesis so there is nothing more that can be
said on the matter - and so it mercifully ends the conversation.

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tychonoff
I never forgot a quote attributed to Liebnitz in my high school trigonometry
book, which went something like:

"Although the world may be a dream, I would call that dream real enough if,
using reason well, I was never deceived by it"

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Florin_Andrei
The whole quantum physics is just in such a dubious, uncertain stage. We don't
know for sure whether its models are "real" or merely a useful tool.

~~~
alphaBetaGamma
I disagree, you can push quantum physics _very_ hard, in weird corners where
is is manifestly wrong. Then you do the experiments, surprise surprise,
quantum mechanics turn out to be right. E.g. Single Photon Interference

~~~
eru
As long as you stick to mathematics and numbers, quantum mechanic is really
robust.

Just don't start interpreting that monster. There be dragons.

