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Re: [Phys-L] scientific consistency



On 06/11/2013 11:58 AM, Bruce Sherwood wrote:
I can't check the work of all other scientists, whether in physics or other
science. But I can and do check whether some scientific result seems
consistent with other science. This consistency check is hugely important

Yes, it's hugely important.

Feynman described science as a grand tapestry. Any forgotten,
unknown, or dubious fact is like a hole in the tapestry. The
damage can be repaired by weaving up from the bottom, down from
the top, in from the sides, or (better!) all of the above.

This point is often lost on students, because all-too-often
they are lucky to understand each idea in one way, let alone
N different ways. Still, the point remains super-important
and needs to be emphasized in class. Every so often, ask
the class to play Six Degrees of Kelvin Baryon, or do some
other exercise that involves looking for connections between
ideas. There isn't time to do more than a tiny bit of that
in class, so the real lesson is that they need to play that
game on their own time, all day every day.

=============

The rule is that every physics idea is so strongly connected
to N other ideas that there is no wiggle room.

There are rare /exceptions/ to this rule. The rarity itself
makes such things interesting.

One example is the debate over the "two fluid" model of
electricity as opposed to the "one fluid" model. For most
of the last 266 years, there was not, IMHO, convincing
evidence against either theory. It was almost as arbitrary
as the parallel postulate in geometry: You could postulate
it either way.

This changed in 1932 with the discovery of the neutron and
especially the positron. For the last 80 years, the idea
that there could be two kinds of electricity ("vitreous"
electricity and "resinous" electricity) has been completely
untenable. We now know absolutely that there is only one
kind of charge. Charge is an abstraction that is described
by *one* number, not two.

Whenever there are two kinds of things, like apples and oranges,
it takes two numbers to keep track of them. There is only one
kind of charge, and it takes only one number to keep track of
it. For the details on this, see
http://www.av8n.com/physics/one-kind-of-charge.htm

The bizarre thing is that it seems to be an article of faith
in the PER community that there are «two kinds of charge».
*) Knight says there are «two kinds of charge».
*) Chabay and Sherwood says there are «two kinds of charge».
*) Arons goes on at great length about it, and marshals a
great deal of evidence, and then comes to exactly the
wrong conclusion. It is wrong twice over.
-- It is wrong to say the one-fluid model is not
viable. It has been viable since 1747, and there has
never been the slightest evidence against it. Indeed
the word "charge" itself, as well as "positive" and
"negative", were introduced for exactly this reason, to
describe a surplus or deficit of this /one/ kind of
electricity.
-- It is wrong to say that the two-fluid model is viable.
It has been dead as a doornail for at least 80 years.

Checking is super-important, but it doesn't get done nearly
as much as it should. There is a tremendous tendency for
textbooks to quote previous textbooks, without sufficient
checking.