Re: Lizard engines and rat engines


"Tim Tyler" <tim@xxxxxxxxxxx> wrote in message news:db6va6$qrd$1@xxxxxxxxxxxxxxxxxxxxxx
> Perplexed in Peoria <jimmenegay@xxxxxxxxxxxxx> wrote or quoted:
> > "Tim Tyler" <tim@xxxxxxxxxxx> wrote in message news:db2791$2a2n$1@xxxxxxxxxxxxxxxxxxxxxx
> > > Perplexed in Peoria <jimmenegay@xxxxxxxxxxxxx> wrote or quoted:
>
> > > > First, according to the thermodynamics textbooks, a "closed system" smaller
> > > > than the universe as a whole is not only possible, it is an essential concept
> > > > in the idea structure. Thermodynamics textbooks are not written in code.
> > >
> > > Are you /sure/ they are saying that? They might be saying that you can
> > > build reasonable models of systems that assume no interaction with
> > > their enviroments - but do you /really/ think they are claiming such
> > > models accurately represent what is going on?
> >
> > What you think a "closed system" is and what the textbooks define a closed
> > system to be are apparently quite different. Check a textbook. A closed
> > system does interact with its environment.
> >
> > I stand by my claim that the notion of a closed system smaller than the
> > universe is an essential part of the idea structure in thermodynamics.
> > And, if it is possible for a system to be in thermal equilibrium with
> > its surroundings (another essential element of the idea structure), then
> > yes, closed systems really can exist.
> >
> > You have an extremely bizarre, almost Edserian phobia of models if you think
> > that fluxes of neutrinos, photinos, or whatever mean that we have to throw
> > out standard thermodynamic terminology and standard thermodynamic reasoning.
> >
> > Apparently, your view is that NO MODEL accurately represents what is going on.
> > Do you really believe that this view is useful?
>
> Er - this is a *terminological* issue. It's about the meaning(s) of the
> term "closed".

Tim, I was replying to your implied PHYSICAL and/or EPISTEMOLOGICAL
claim that a system smaller than the universe which does not exchange
energy (and/or matter) with the rest of the universe can not possibly
be an accurate model of what is going on. You repeat this claim below
with your e=mc^2 remark.

> Personally, I see no problem with using "closed" to mean:
>
> ``Closed system. A physical system on which no outside influences act;
> closed so that nothing gets in or out of the system and nothing from
> outside can influence the system's observable behavior or properties.''
>
> - http://www.lhup.edu/~dsimanek/glossary.htm
>
> ``An open system can be influenced by events outside of the declared
> boundaries of a system. A closed system is self-contained: outside
> events can have no influence upon the system.''
>
> - http://en.wikipedia.org/wiki/System#Types_of_systems
>
> Obviously this usage rubs you up the wrong way.

No, it doesn't. It is perfectly fine useage in systems theory.

What rubs me the wrong way is when that usage takes
place without warning in a discussion of thermodynamics, a field in
which the standard usage is quite different. In my mind, it was you
that created the confusion by writing something misleading to anyone
who knows anything about thermodynamics. You did so after having
been warned that there was a problem. And now you seem to be trying
to justify this behavior. Your reasons for doing so, quite frankly,
mystify me.

> However, I /like/ using "closed" in this way - and apparently so do
> a very large number of other people.
>
> I doubt efforts to get me to use closed to refer to the - IMO - rather
> esoteric idea of a system isolated in terms of its atoms and matter -
> but not thermally - are going to prove effective.

:-(

> Since E=mc^2 tells us that energy and mass are fundamentally
> interchangable, the whole idea doesn't make very much sense to me.

That comment MIGHT make some sense if e=mc^2 had been known when the
standard terminology of thermodynamics was being hammered out. But
it wasn't. Now that we know about relativity, I'm sure that someone
has worked out just how the basic definitions and theorems need to
be changed.

I am familiar with how that process played out in
mechanics. Some formulas are still valid (though the terms have
slightly different meanings). Some formulas have to be modified
by adding one of those ugly Lorentz terms.

I am not familiar with how that process played out for thermodynamics.
Bekenstein and Hawking worked out the details only recently.
Apparently, entropy needs to be redefined so as to involve the
surface area of any black holes in the system. But since I use
thermodynamics only for biochemistry, I haven't bothered to learn
the details. I only carry my calculations to two decimal places.
But I have seen thermodynamics used in an analysis of stellar
structure, and the fact that the star is losing mass as a result
of fusion reactions didn't seem to bother anyone.

Tim, just in case my sarcasm in the previous paragraphs didn't
come through, what I am really saying is that invoking e=mc^2
is grasping at straws. I have no idea why you think that doing
so is reasonable.

> For another thing, it would be an example of non-self-explanatory
> terminology: nowhere in the term "closed system" does it say that
> that the closure applies to physical matter, but not to heat or signals.
>
> Introducing that sort hidden detail in a common term which is basically
> two ordinary english words joined together is one of the many ways in
> which misunderstandings and misconceptions start.

Uh oh. Say goodbye to:

Natural selection
Relative fitness
Absolute fitness
Energy flow
Power curve
Dissipative structure
Black hole
News group
Systems analyst
Population structure
Slide show
Group selection
and finally
Scientific communication


.

Relevant Pages

  • Re: Lizard engines and rat engines
    ... Thermodynamics textbooks are not written in code. ... > What you think a "closed system" is and what the textbooks define a closed ... outside can influence the system's observable behavior or properties.'' ...
    (sci.bio.evolution)
  • Re: Lizard engines and rat engines
    ... Thermodynamics textbooks are not written in code. ... > doesn't say that the entropy of a closed system must not decrease. ... > water in a bottle, stopper the bottle, and put the bottle in your freezer. ...
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    ... The top ones were all tutorials on thermodynamics. ... some incorrect inferences. ... am not using the survey to justify my position that a "closed system" ... I DID do a sympathetic reading. ...
    (sci.bio.evolution)
  • Re: Lizard engines and rat engines
    ... The top ones were all tutorials on thermodynamics. ... The second law says that the amount of random movement, i.e. the entropy, ... can only increase in a closed system, i.e. that we cannot put this ... quotes a textbook of thermodynamics, physics, chemistry, or engineering ...
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