🚀 go-pugleaf

andrew@rentec.com (Andrew Mullhaupt) writes...
>>But this is beside the point. Real people who ask why the sky is blue are
>>taking for granted that the night sky is dark since every child knows this.
> 
>So a scientist cannot ask this question unless he wants to cease being real?

'Real' means non-scientist non-philosopher. A scientist who asks this question
is also taking for granted that the sky is dark. A philosopher maybe not. As
Feynman used to say, Physics is just an extension of common sense.

>You are in danger of fragmenting physics into a disconnected set of fragmentary
>explanations valid only in the neighborhood of legitimate observations.

I don't know why it has to be disconnected. But the rest of your statement is
correct.

>                                                                        This
>kind of physics has very strange versions of things like the second law of
>thermodynamics.

Impressive insight! Do you know how many very strange versions of the
second law we have?

>My main objection to taking things for granted since they are common is
>that the common observations deserve the priority in scientific explanation,
>since the common observations are the most "confirmed". Not all of them are
>so easy to explain, either.

I didn't say they should never be explained. But 'why is the sky blue?' does
not ask that the assumptions be explained.

>>And I claim it is OK to ignore supernovae, even though without them there
>>would not be an earth.
>
>Not really. And you ultimately have to explain where the atmosphere comes from,
>etc. My point is that the question "why is the sky blue?" is a question about
>a view of reality. When you take it for granted that the source of the daytime
>illumination is the sun, wou are explaining one observation (sky is blue) in
>terms of another one (daylight is sunlight). Such explanation is actually
>like free association - it is a matter of choice where to stop.

I agree. But in most cases its obvious.

>As far as I can tell, you can't get anywhere in physics without making any
>of these choices. The consequence is that what you call physics is what you
>have chosen to call physics.

I agree.

>Note that the scientific method does not make these choices for you. The
>scientific method is essentially intact even if you decide that 'observation'
>means conducting an a priori computation using Conway's cellular automaton.

The scientific method is just that, a method. It is useful because it helps
one to remain objective. I think it's missing the point if you define science
in terms of it.

>In one sense this is obvious - you can do science on some restricted piece
>of the 'universe', but the upshot is that you cannot use the scientific method
>to guarantee that your choices of observations are in any sense 'complete',
>since the method is perfectly happy with a restricted choice.

Is it really possible to achieve 'completeness?' Some people think it is 
possible, but we're not there yet!

>In view of this, where is it reasonable to stop? Is the widespread feeling that
>the universe is 'understandable' (Cf. remarks of Einstein, Wigner) anything
>more than the fact that we can explain what we have chosen to limit our
>explanations to?

We choose to limit our explanations to those phenomena that we _can_ explain.
(unlike philosophers! ;)

The feeling you mention is a result of the observation that very few questions
have remained unexplained for long.

>If physicist were happy to stop, why do they want either an SSC or the money
>to be spent in some other part of physics?

Because the SSC can help to answer questions of the type which we know by
experience are answerable. Also, since the Higgs mechanism directly effects
almost everything, then the SSC is _required_ to answer virtually any
question _you_ might ask. Of course that's not true of questions that
REAL people ask. ;-) Maybe that's why it's so hard to get funding.

Dave Ring
dwr2560@zeus.tamu.edu