Logic in natural sciences (was: Heat as an indestructible substance)

[Pentcho Valev <pvalev@BAS.BG>]

Bob Sciamanda wrote:

> Hi Pentcho,
> Rather than haggle about the details of Carnot's argumentation, I'll give you a
> better example of how science, proceeding in fits and starts, often stumbles
> upon the "truth" through paths which are later recognized as insecure.  I refer
> to our discovery and development of the conservation of momentum.  It was first
> derived (and still is in textbooks) from Newton's laws of motion, a crucial
> premise being the third law.  With the discovery of the magnetic force between
> moving charges, it was realized that there were forces that did not obey
> Newton's third law.  Surprisingly, this did not invalidate our conservation of
> momentum conclusion - we merely raised it to the level of an a-priori
> hypothesis, assigned the missing momentum to the electromagnetic field, and
> produced a consistent and testable model of particle interactions.
>
> Nature's pedagogy may at times lead us to useful conclusions through imperfect
> premises.  After we find the imperfections, we do the polishing; but we don't
> through out a useful baby with the used bath water.

I fully agree but let me call your attention to the following. If the premise
proves false but scientists very much want the conclusion to be true, the
conclusion must be declared as EMPIRICAL and accordingly must undergo countless
experimental tests. This did not happen in thermodynamics. Carnot's conclusion,
which can be generalized as

"An engine cannot absorb heat from a reservoir, completely convert it into work and
return to its initial state"

has in fact never been tested experimentally. Rather, Clausius and Kelvin INVALIDLY
deduced it from

"Heat cannot move from a cold to a hot body in the absence of other associated
changes"

which is obviously an experience of mankind (has been tested countless times). So
the problem of experimental testing disappeared and today's thermodynamicists don't
even see why it should be raised.
I think that a course of logic is absolutely necessary for students in natural
sciences. I have been working for some time on this but the task has proved
extremely difficult. Still, if someone wants to see my initial efforts, please see
my paper "Introducing logic in chemical thermodynamics courses". Just click on
"Papers and lecture texts" in

http://uk.groups.yahoo.com/group/learning-science-concepts/files/

and then see "Thermodynamics (Valev2)".

Best regards,
Pentcho