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Re: should c be a subset of c++?

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  Re: should c be a subset of c++? "J. Clarke" <j.clarke.873638@gmail.com> - 2015-11-06 19:06 -0500
    Re: should c be a subset of c++? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-07 00:41 -0800
      Re: should c be a subset of c++? Richard Damon <Richard@Damon-Family.org> - 2015-11-07 10:01 -0500
        Re: should c be a subset of c++? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-07 09:12 -0800
          Re: should c be a subset of c++? Martin Shobe <martin.shobe@yahoo.com> - 2015-11-07 11:58 -0600
            Re: should c be a subset of c++? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-07 10:25 -0800
              Re: should c be a subset of c++? Keith Thompson <kst-u@mib.org> - 2015-11-07 11:54 -0800
                Re: should c be a subset of c++? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-07 14:22 -0800
                  Re: should c be a subset of c++? Martin Shobe <martin.shobe@yahoo.com> - 2015-11-08 13:05 -0600
                    Re: should c be a subset of c++? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-08 11:39 -0800
                      Re: should c be a subset of c++? Geoff <geoff@invalid.invalid> - 2015-11-13 13:20 -0800
                        Re: should c be a subset of c++? James Kuyper <jameskuyper@verizon.net> - 2015-11-13 16:36 -0500
                        Re: should c be a subset of c++? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-14 00:03 +0000
                          Re: should c be a subset of c++? Geoff <geoff@invalid.invalid> - 2015-11-13 17:06 -0800
                      Re: should c be a subset of c++? Geoff <geoff@invalid.invalid> - 2015-11-13 13:29 -0800
              Re: should c be a subset of c++? Martin Shobe <martin.shobe@yahoo.com> - 2015-11-08 12:57 -0600
                Re: should c be a subset of c++? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-08 11:37 -0800
                  Re: should c be a subset of c++? Keith Thompson <kst-u@mib.org> - 2015-11-08 17:16 -0800
                    Re: should c be a subset of c++? supercat@casperkitty.com - 2015-11-08 18:19 -0800
                  Re: should c be a subset of c++? Martin Shobe <martin.shobe@yahoo.com> - 2015-11-08 23:25 -0600
                  Re: should c be a subset of c++? Gareth Owen <gwowen@gmail.com> - 2015-11-10 22:34 +0000
          Re: should c be a subset of c++? raltbos@xs4all.nl (Richard Bos) - 2015-11-13 22:18 +0000
            Re: should c be a subset of c++? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-14 00:11 +0000
              Re: should c be a subset of c++? raltbos@xs4all.nl (Richard Bos) - 2015-11-17 22:16 +0000
                Re: should c be a subset of c++? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-17 21:09 -0800
                  Re: should c be a subset of c++? Richard Heathfield <rjh@cpax.org.uk> - 2015-11-18 05:22 +0000
                  Re: should c be a subset of c++? Keith Thompson <kst-u@mib.org> - 2015-11-18 06:03 -0800
                    Re: should c be a subset of c++? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-18 08:44 -0800
                      Re: should c be a subset of c++? Keith Thompson <kst-u@mib.org> - 2015-11-18 09:11 -0800
                        Re: should c be a subset of c++? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-18 09:54 -0800
                          Re: should c be a subset of c++? Philip Lantz <prl@canterey.us> - 2015-11-24 01:49 -0800
                            Re: should c be a subset of c++? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-24 02:58 -0800
                              Re: should c be a subset of c++? raltbos@xs4all.nl (Richard Bos) - 2015-11-24 11:58 +0000
                              Re: should c be a subset of c++? Keith Thompson <kst-u@mib.org> - 2015-11-24 09:09 -0800
                                Re: should c be a subset of c++? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-25 00:12 -0800
                                  Re: should c be a subset of c++? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-25 12:35 +0000
                                  Re: should c be a subset of c++? raltbos@xs4all.nl (Richard Bos) - 2015-11-27 16:30 +0000
                      Re: should c be a subset of c++? raltbos@xs4all.nl (Richard Bos) - 2015-11-19 10:37 +0000
                      Re: should c be a subset of c++? Tim Rentsch <txr@alumni.caltech.edu> - 2015-11-20 15:40 -0800
    Re: should c be a subset of c++? Gareth Owen <gwowen@gmail.com> - 2015-11-10 22:20 +0000

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#75199 — Re: should c be a subset of c++?

In article <29c78bf7-83d1-4497-b9c5-bee6b774f5ad@googlegroups.com>, 
malcolm.mclean5@btinternet.com says...
> 
> On Sunday, September 6, 2015 at 8:01:41 PM UTC+1, Rick C. Hodgin wrote:
> > 
> > I do realize that.  I'm adding a definition to it, which in all honesty,
> > is a new thing to my thinking as prompted by the course of this thread.
> > 
> > In my use, a real value is something that can be expressed finitely
> > in computed digits rather than concepts, meaning it has a termination
> > point that is achievable, such as 5.25.  It is a finite value that can
> > be fully expressed in our universe as that value.  In that sense, it
> > is real.  An unreal number is something like e or pi which goes on and
> > on.  They are usable in our universe through approximation, but the
> > result we get is not a real result, only an applied version of the
> > real result which would exist in another universe where the infinite
> > values we observe are not infinite, or, at least, are commensurate
> > with the infinite nature of that existence, meaning in such a context,
> > they too are finite (relatively).
> > 
> > Does this make sense to no one?  It's not difficult.  It's just
> > different.
> > 
> "Real" is mathematicianese for "analogue". Most things in the world
> that we measure are continuous, at least on any human scale (obviously
> a quantity of water has to be a whole number of H2O atoms, but we
> can't even approach that measurement with ordinary equipment, it's
> usual to consider it continuous). There are also imaginary numbers,
> which are the square roots of negative numbers. Negatives are also
> considered "real".
> Except maybe at the point where it becomes difficult to distinguish
> maths from physics, you can't have a physical negative quantity.
> You can be in debt to the bank, but you can't have -5 coins with
> the Queen's head on in your pocket - the debt is purely a social
> convention or fiction, it only as meaning as long as we as a society
> agree that it has meaning. The coins in your pocket aren't - Elizabeth 
> II could declare pound coins to be no longer legal tender, but that
> wouldn't make them vanish into thin air.
> 
> Whether you can have two objects which are exactly in the proportion 
> 1:PI in the real world, I wouldn't like to say, but you can certainly
> have two objects which are as close to that proportion as can be
> measured.

Malcolm, if you think that negative values have no reality in physics 
you have not passed freshman physics at any accredited university.

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#75229

On Saturday, November 7, 2015 at 12:05:18 AM UTC, J. Clarke wrote:
> In article <29c78bf7-83d1-4497-b9c5-bee6b774f5ad@googlegroups.com>, 
> 
> Malcolm, if you think that negative values have no reality in physics 
> you have not passed freshman physics at any accredited university.
>
Electrons have a "negative charge". Except they don't. You could just
as easily say they have a positive charge and flip all the signs in
every publication on physics and electricity, and no errors would
be introduced.
But I haven't passed freshman physics at university. I have far
more degrees than the average person, but physics isn't amongst them. 

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#75263

On 11/7/15 3:41 AM, Malcolm McLean wrote:
> On Saturday, November 7, 2015 at 12:05:18 AM UTC, J. Clarke wrote:
>> In article <29c78bf7-83d1-4497-b9c5-bee6b774f5ad@googlegroups.com>,
>>
>> Malcolm, if you think that negative values have no reality in physics
>> you have not passed freshman physics at any accredited university.
>>
> Electrons have a "negative charge". Except they don't. You could just
> as easily say they have a positive charge and flip all the signs in
> every publication on physics and electricity, and no errors would
> be introduced.
> But I haven't passed freshman physics at university. I have far
> more degrees than the average person, but physics isn't amongst them.
>

At which point Protons will have negative charge, so you haven't gotten 
rid of negative values.

Yes, SOME types of values are inherently "Positive only", as they are 
scalars with no concept of direction. A good example of this is how much 
of something you have, or the 'speed' of an object.

Some types naturally have positive and negative values, things that can 
cancel out. Things like 'Charge' (or wealth).

Lastly you have things that have a value that includes a full 
directionality in mufti-dimensional space, things like velocity.

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#75270

On Saturday, November 7, 2015 at 3:01:48 PM UTC, Richard Damon wrote:
> On 11/7/15 3:41 AM, Malcolm McLean wrote:
>
> At which point Protons will have negative charge, so you haven't gotten 
> rid of negative values.
> 
> Yes, SOME types of values are inherently "Positive only", as they are 
> scalars with no concept of direction. A good example of this is how much 
> of something you have, or the 'speed' of an object.
> 
> Some types naturally have positive and negative values, things that can 
> cancel out. Things like 'Charge' (or wealth).
> 
> Lastly you have things that have a value that includes a full 
> directionality in mufti-dimensional space, things like velocity.
>
So can you come up with a value that is inherently negative only?
Temperature? Can we say that absolute zero is in fact the "highest"
possible temperature, and all temperatures are "really" negative?
Or is that in fact not meaningful? Certainly the main in the street
considers room temperature to be "higher" than the temperature
of his fridge, and it's a workable mental model.

In the proton electron case, the signs are just a convention.
There's no reason why electrons are negative, other than historical
accident.
But you've reached the limits of my non-freshman physical understanding
there. I don't really know whether that means that we can say that
the sign system is also a abstraction we impose.

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#75275

On 11/7/2015 11:12 AM, Malcolm McLean wrote:
> On Saturday, November 7, 2015 at 3:01:48 PM UTC, Richard Damon wrote:
>> On 11/7/15 3:41 AM, Malcolm McLean wrote:
>>
>> At which point Protons will have negative charge, so you haven't gotten
>> rid of negative values.
>>
>> Yes, SOME types of values are inherently "Positive only", as they are
>> scalars with no concept of direction. A good example of this is how much
>> of something you have, or the 'speed' of an object.
>>
>> Some types naturally have positive and negative values, things that can
>> cancel out. Things like 'Charge' (or wealth).
>>
>> Lastly you have things that have a value that includes a full
>> directionality in mufti-dimensional space, things like velocity.
>>
> So can you come up with a value that is inherently negative only?

It would be the exact same category as the "Positive only".

> Temperature? Can we say that absolute zero is in fact the "highest"
> possible temperature, and all temperatures are "really" negative?

Yes.

> Or is that in fact not meaningful? Certainly the main in the street
> considers room temperature to be "higher" than the temperature
> of his fridge, and it's a workable mental model.

It's also workable the other way around, we just aren't used to doing 
things that way.

> In the proton electron case, the signs are just a convention.
> There's no reason why electrons are negative, other than historical
> accident.

> But you've reached the limits of my non-freshman physical understanding
> there. I don't really know whether that means that we can say that
> the sign system is also a abstraction we impose.

The sign system is an abstraction we impose. It's more a question of how 
well it matches up with reality. For some things, such as charge, it 
works extremely well. For other things, such as speed, it doesn't.

Martin Shobe

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#75280

On Saturday, November 7, 2015 at 5:58:54 PM UTC, Martin Shobe wrote:
> On 11/7/2015 11:12 AM, Malcolm McLean wrote:
> 
> > Temperature? Can we say that absolute zero is in fact the "highest"
> > possible temperature, and all temperatures are "really" negative?
> 
> Yes.
> 
So there we've got an example of what you consider to be a real negative
quantity. Temperature is "really" on a scale with absolute zero
being the maximum, and everything else -X below it.
>
> > Or is that in fact not meaningful? Certainly the main in the street
> > considers room temperature to be "higher" than the temperature
> > of his fridge, and it's a workable mental model.
> 
> It's also workable the other way around, we just aren't used to doing 
> things that way.
>
So obviously, since all temperatures are really negative, a scale
that went from 0 at absolute zero to negative would be workable,
it would be extraordinary if it didn't. But in fact we don't use 
such a scale, at least commonly. Which leads me to wonder if 
temperatures are "really" negative or it's like a negative bank
balance - convenient notation, but representing a social agreement
and not a physical reality.
>
> The sign system is an abstraction we impose. It's more a question of how 
> well it matches up with reality. For some things, such as charge, it 
> works extremely well. For other things, such as speed, it doesn't.
> 

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#75288

Malcolm McLean <malcolm.mclean5@btinternet.com> writes:
> On Saturday, November 7, 2015 at 5:58:54 PM UTC, Martin Shobe wrote:
>> On 11/7/2015 11:12 AM, Malcolm McLean wrote:
>> > Temperature? Can we say that absolute zero is in fact the "highest"
>> > possible temperature, and all temperatures are "really" negative?
>> 
>> Yes.
>> 
> So there we've got an example of what you consider to be a real negative
> quantity. Temperature is "really" on a scale with absolute zero
> being the maximum, and everything else -X below it.

I don't think Martin was saying that that's the "real" way to
consider temperatures, merely that we *can* look at them that way.

For example, the Celsius scale originally water freezing at 100
degrees and boiling at 0; it was reversed after Celsius's death.
The modern version makes better physical sense, since higher
temperatures correspond to higher energy -- but either would be
workable.

[...]

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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#75302

On Saturday, November 7, 2015 at 7:54:25 PM UTC, Keith Thompson wrote:
> Malcolm McLean <malcolm.mclean5@btinternet.com> writes:
> 
> I don't think Martin was saying that that's the "real" way to
> consider temperatures, merely that we *can* look at them that way.
> 
> For example, the Celsius scale originally water freezing at 100
> degrees and boiling at 0; it was reversed after Celsius's death.
> The modern version makes better physical sense, since higher
> temperatures correspond to higher energy -- but either would be
> workable.
> 
No, that's the point.
Defining low temperatures as "higher" makes more physical sense.
That's why it's easy to design technology to heat things up, a lot
harder to design technology to cool things down.

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#75348

On 11/7/2015 4:22 PM, Malcolm McLean wrote:
> On Saturday, November 7, 2015 at 7:54:25 PM UTC, Keith Thompson wrote:
>> Malcolm McLean <malcolm.mclean5@btinternet.com> writes:
>>
>> I don't think Martin was saying that that's the "real" way to
>> consider temperatures, merely that we *can* look at them that way.
>>
>> For example, the Celsius scale originally water freezing at 100
>> degrees and boiling at 0; it was reversed after Celsius's death.
>> The modern version makes better physical sense, since higher
>> temperatures correspond to higher energy -- but either would be
>> workable.
>>
> No, that's the point.
> Defining low temperatures as "higher" makes more physical sense.

And if you were measuring the absence of energy, the negative only would 
make "physical sense" and the positive only would not.

> That's why it's easy to design technology to heat things up, a lot
> harder to design technology to cool things down.

No, the reason refrigeration is harder than heating has to do with entropy.

Martin Shobe

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#75352

On Sunday, November 8, 2015 at 7:05:33 PM UTC, Martin Shobe wrote:
> On 11/7/2015 4:22 PM, Malcolm McLean wrote:
>
> > That's why it's easy to design technology to heat things up, a lot
> > harder to design technology to cool things down.
> 
> No, the reason refrigeration is harder than heating has to do with 
> entropy.
>
Which is why you can argue that cold temperatures are "really" more
positive than high temperatures.

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#75971

On Sun, 8 Nov 2015 11:39:43 -0800 (PST), Malcolm McLean
<malcolm.mclean5@btinternet.com> wrote:

>On Sunday, November 8, 2015 at 7:05:33 PM UTC, Martin Shobe wrote:
>> On 11/7/2015 4:22 PM, Malcolm McLean wrote:
>>
>> > That's why it's easy to design technology to heat things up, a lot
>> > harder to design technology to cool things down.
>> 
>> No, the reason refrigeration is harder than heating has to do with 
>> entropy.
>>
>Which is why you can argue that cold temperatures are "really" more
>positive than high temperatures.
>

The Kelvin (absolute) temperature scale was derived from the
interpolation of the previous (relative) scales of Fahrenheit, Celsius
and other at the time. William Kelvin desired an "absolute cold" point
or "absolute zero" temperature. He interpolated the slope of the
Centigrade scale and calculated that -273 degrees Centigrade was the
absolute zero point he was seeking. 

It was later standardized that the triple-point of water is exactly
273.16 Kelvin and this is an arbitrary standard.

Theoretically, nothing can be colder than 0 Kelvin. All molecular
motion ceases and all matter is "frozen". There is conceptually, no
such thing as negative Kelvins and no such concept as colder than
absolute cold.

Entropy is the measure of the number of energy states a system can
assume. The third law of thermodynamics states "The entropy of a
perfect crystal at absolute zero is exactly equal to zero." An
arbitrary object of any type can only approximate this ideal. 

Therefore, a state of absolute zero cannot be physically achieved,
except perhaps, at the end of time and space and the heat death of the
universe. But even this state defies logic since the second law of
thermodynamics states that the entropy of a closed system constantly
increases. A finite universe, being a closed system must obey the
second law. Only an infinite universe with a finite amount of energy
can be in a state of absolute zero entropy.

Hawking has shown that a black hole has maximum entropy of any body of
equal size. Therefore the end state of the universe is a black hole.
Internally, the black hole can do no work and it possesses no internal
temperature gradient. This does not mean the temperature of the
universe or a black hole is absolute zero. Zero relative entropy means
zero temperature differences within the system of interest.

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#75974

On 11/13/2015 04:20 PM, Geoff wrote:
...
> The Kelvin (absolute) temperature scale was derived from the
> interpolation of the previous (relative) scales of Fahrenheit, Celsius
> and other at the time. William Kelvin desired an "absolute cold" point
> or "absolute zero" temperature. He interpolated the slope of the
> Centigrade scale and calculated that -273 degrees Centigrade was the
> absolute zero point he was seeking. 
> 
> It was later standardized that the triple-point of water is exactly
> 273.16 Kelvin and this is an arbitrary standard.
> 
> Theoretically, nothing can be colder than 0 Kelvin. All molecular
> motion ceases and all matter is "frozen". There is conceptually, no
> such thing as negative Kelvins ...

Not quite - but the exceptions are rather odd systems:
<https://en.wikipedia.org/wiki/Negative_temperature>

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#75992

Geoff <geoff@invalid.invalid> wrote:

(snip, and previous snip, on negative numbers)

> The Kelvin (absolute) temperature scale was derived from the
> interpolation of the previous (relative) scales of Fahrenheit, Celsius
> and other at the time. William Kelvin desired an "absolute cold" point
> or "absolute zero" temperature. He interpolated the slope of the
> Centigrade scale and calculated that -273 degrees Centigrade was the
> absolute zero point he was seeking. 
 
> It was later standardized that the triple-point of water is exactly
> 273.16 Kelvin and this is an arbitrary standard.

Yes. The freezing point of water at atmospheric pressure is close
to 273.15 K, but the definition is on the triple point.
 
> Theoretically, nothing can be colder than 0 Kelvin. All molecular
> motion ceases and all matter is "frozen". There is conceptually, no
> such thing as negative Kelvins and no such concept as colder than
> absolute cold.

Well, actually not:

https://en.wikipedia.org/wiki/Zero-point_energy

quantum mechanics requires motion even at absolute zero, and helium
is a (superfluid) liquid at absolute zero and 1 atmosphere. 

If motion ceases, both the position and momentum would be known
exactly, but Heisenburg uncertainty doesn't allow for that. 
 
> Entropy is the measure of the number of energy states a system can
> assume. The third law of thermodynamics states "The entropy of a
> perfect crystal at absolute zero is exactly equal to zero." An
> arbitrary object of any type can only approximate this ideal. 

Turns out that superfluid liquids, in which all atoms are in the
same quantum state, can also have zero entropy.
 
> Therefore, a state of absolute zero cannot be physically achieved,
> except perhaps, at the end of time and space and the heat death of the
> universe. But even this state defies logic since the second law of
> thermodynamics states that the entropy of a closed system constantly
> increases. A finite universe, being a closed system must obey the
> second law. Only an infinite universe with a finite amount of energy
> can be in a state of absolute zero entropy.

But you can get darn close if you try hard enough.
 
> Hawking has shown that a black hole has maximum entropy of any body of
> equal size. Therefore the end state of the universe is a black hole.
> Internally, the black hole can do no work and it possesses no internal
> temperature gradient. This does not mean the temperature of the
> universe or a black hole is absolute zero. Zero relative entropy means
> zero temperature differences within the system of interest.

-- glen

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#75994

On Sat, 14 Nov 2015 00:03:14 +0000 (UTC), glen herrmannsfeldt
<gah@ugcs.caltech.edu> wrote:

>Geoff <geoff@invalid.invalid> wrote:
>
>(snip, and previous snip, on negative numbers)
>
>> The Kelvin (absolute) temperature scale was derived from the
>> interpolation of the previous (relative) scales of Fahrenheit, Celsius
>> and other at the time. William Kelvin desired an "absolute cold" point
>> or "absolute zero" temperature. He interpolated the slope of the
>> Centigrade scale and calculated that -273 degrees Centigrade was the
>> absolute zero point he was seeking. 
> 
>> It was later standardized that the triple-point of water is exactly
>> 273.16 Kelvin and this is an arbitrary standard.
>
>Yes. The freezing point of water at atmospheric pressure is close
>to 273.15 K, but the definition is on the triple point.
> 
>> Theoretically, nothing can be colder than 0 Kelvin. All molecular
>> motion ceases and all matter is "frozen". There is conceptually, no
>> such thing as negative Kelvins and no such concept as colder than
>> absolute cold.
>
>Well, actually not:
>
>https://en.wikipedia.org/wiki/Zero-point_energy
>
>quantum mechanics requires motion even at absolute zero, and helium
>is a (superfluid) liquid at absolute zero and 1 atmosphere. 
>
>If motion ceases, both the position and momentum would be known
>exactly, but Heisenburg uncertainty doesn't allow for that. 
>

For Kelvin and his peers, this was unknown and for purposes of
discussion it was irrelevant so I ignored it.

QM describes the motion of and state of "particles as waves". While
the QM state of an atom is a wave function, that atom "freezes" at
absolute zero in a lattice and vibrates in place. Since observation of
the atom requires photons to observe its state, the presence of the
energy in the lattice raises it above absolute zero. If the motion is
less than the Plank length then it's unobservable anyway. For all
intents and purposes it has vanished.

>> Entropy is the measure of the number of energy states a system can
>> assume. The third law of thermodynamics states "The entropy of a
>> perfect crystal at absolute zero is exactly equal to zero." An
>> arbitrary object of any type can only approximate this ideal. 
>
>Turns out that superfluid liquids, in which all atoms are in the
>same quantum state, can also have zero entropy.
>

The idea was a "perfect crystal" in a "perfect state of absolute zero"
which cannot exist except in a classical mechanical context. Quantum
mechanics was unknown by Kelvin at the time.

>> Therefore, a state of absolute zero cannot be physically achieved,
>> except perhaps, at the end of time and space and the heat death of the
>> universe. But even this state defies logic since the second law of
>> thermodynamics states that the entropy of a closed system constantly
>> increases. A finite universe, being a closed system must obey the
>> second law. Only an infinite universe with a finite amount of energy
>> can be in a state of absolute zero entropy.
>
>But you can get darn close if you try hard enough.
> 
>> Hawking has shown that a black hole has maximum entropy of any body of
>> equal size. Therefore the end state of the universe is a black hole.
>> Internally, the black hole can do no work and it possesses no internal
>> temperature gradient. This does not mean the temperature of the
>> universe or a black hole is absolute zero. Zero relative entropy means
>> zero temperature differences within the system of interest.
>
>-- glen

Then comes the concept of the singularity universe and "how hot was
it?" The singularity universe and the Big Bang defies the second law
of thermodynamics since a singularity has no temperature gradient and
in Kelvin's world, work could never be done in the classical sense.

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#75973

On Sun, 8 Nov 2015 11:39:43 -0800 (PST), Malcolm McLean
<malcolm.mclean5@btinternet.com> wrote:

>On Sunday, November 8, 2015 at 7:05:33 PM UTC, Martin Shobe wrote:
>> On 11/7/2015 4:22 PM, Malcolm McLean wrote:
>>
>> > That's why it's easy to design technology to heat things up, a lot
>> > harder to design technology to cool things down.
>> 
>> No, the reason refrigeration is harder than heating has to do with 
>> entropy.
>>
>Which is why you can argue that cold temperatures are "really" more
>positive than high temperatures.
>

There are more than one kind of entropy. Absolute entropy and relative
entropy. The latter is the kind that Earthlings use to produce
mechanical work.

The Kelvin (absolute) temperature scale was derived from the
interpolation of the previous (relative) scales of Fahrenheit, Celsius
and other at the time. William Kelvin conceived of an "absolute cold"
point or "absolute zero" temperature. He interpolated the slope of the
Centigrade scale and calculated that -273 degrees Centigrade was the
absolute zero point he was seeking. 

It was later standardized that the triple-point of water is exactly
273.16 Kelvin and this is an arbitrary standard.

Theoretically, nothing can be colder than zero Kelvin. All molecular
motion ceases and all matter is "frozen". There is conceptually, no
such thing as negative Kelvins and no such concept as colder than
absolute cold. The "order" in the system is maximum, it has only one
state, and absolute entropy is zero, higher temperatures having "more
entropy" than zero.

Entropy is the measure of the number of energy states a system can
assume. The third law of thermodynamics states "The entropy of a
perfect crystal at absolute zero is exactly equal to zero." An
arbitrary object of any type can only approximate this ideal. 

Therefore, a state of absolute zero cannot be physically achieved,
except perhaps, at the end of time and space and the heat death of the
universe. But even this state defies logic since the second law of
thermodynamics states that the entropy of a closed system constantly
increases. A finite universe, being a closed system must obey the
second law. Only an infinite universe with a finite amount of energy
can be in a state of absolute zero entropy.

Hawking has shown that a black hole has maximum entropy of any body of
equal size. Therefore the end state of the universe is a black hole.
Internally, the black hole can do no work and it possesses no internal
temperature gradient. This does not mean the temperature of the
universe or a black hole is absolute zero. Zero relative entropy means
zero temperature differences within the system of interest.

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#75347

On 11/7/2015 12:25 PM, Malcolm McLean wrote:
> On Saturday, November 7, 2015 at 5:58:54 PM UTC, Martin Shobe wrote:
>> On 11/7/2015 11:12 AM, Malcolm McLean wrote:
>>
>>> Temperature? Can we say that absolute zero is in fact the "highest"
>>> possible temperature, and all temperatures are "really" negative?
>>
>> Yes.
>>
> So there we've got an example of what you consider to be a real negative
> quantity. Temperature is "really" on a scale with absolute zero
> being the maximum, and everything else -X below it.

That doesn't follow from what I said. I said you *could* treat 
temperature that way. Anything that can be a positive-only can also be 
negative-only and vice-versa.

>>> Or is that in fact not meaningful? Certainly the main in the street
>>> considers room temperature to be "higher" than the temperature
>>> of his fridge, and it's a workable mental model.
>>
>> It's also workable the other way around, we just aren't used to doing
>> things that way.
>>
> So obviously, since all temperatures are really negative, a scale
> that went from 0 at absolute zero to negative would be workable,
> it would be extraordinary if it didn't.

It is workable.

> But in fact we don't use
> such a scale, at least commonly. Which leads me to wonder if
> temperatures are "really" negative or it's like a negative bank
> balance - convenient notation, but representing a social agreement
> and not a physical reality.

No, it's not like a negative bank balance. The sign for a bank balance 
indicates who owes who. There's nothing analogous for temperature.

>> The sign system is an abstraction we impose. It's more a question of how
>> well it matches up with reality. For some things, such as charge, it
>> works extremely well. For other things, such as speed, it doesn't.

Martin Shobe

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#75351

On Sunday, November 8, 2015 at 6:57:43 PM UTC, Martin Shobe wrote:
> 
> > So there we've got an example of what you consider to be a real negative
> > quantity. Temperature is "really" on a scale with absolute zero
> > being the maximum, and everything else -X below it.
> 
> That doesn't follow from what I said. I said you *could* treat 
> temperature that way. Anything that can be a positive-only can also be 
> negative-only and vice-versa.
> 
That seems obviously wrong to me.
A population can't be negative, surely? It's "really" positive.
Also surface area. If we hold that the area of the Earth is
negative, we'd have to say that the radius is imaginary. It's
not clear to me that that's a workable system of notation.

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#75414

Malcolm McLean <malcolm.mclean5@btinternet.com> writes:
> On Sunday, November 8, 2015 at 6:57:43 PM UTC, Martin Shobe wrote:
>> > So there we've got an example of what you consider to be a real negative
>> > quantity. Temperature is "really" on a scale with absolute zero
>> > being the maximum, and everything else -X below it.
>> 
>> That doesn't follow from what I said. I said you *could* treat 
>> temperature that way. Anything that can be a positive-only can also be 
>> negative-only and vice-versa.
>> 
> That seems obviously wrong to me.
> A population can't be negative, surely? It's "really" positive.

If you're interested in how many more people a region can support, it
might make perfectly good sense to represent the current population
as a negative number.  Perhaps it's not likely, but you can use
whatever representation happens to be convenient.

[...]

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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#75418

On Sunday, November 8, 2015 at 7:16:12 PM UTC-6, Keith Thompson wrote:
> If you're interested in how many more people a region can support, it
> might make perfectly good sense to represent the current population
> as a negative number.  Perhaps it's not likely, but you can use
> whatever representation happens to be convenient.

The sensible kind of value for a population would be a cardinal number type,
which when acted upon promotes to a larger signed numeric type so subtracting
a larger value from a smaller one will yield a negative result.  Unfortunately,
the only cardinal types in C which use their entire storage for value bits are
smaller than "int" [which means that some compilers have a 16-bit cardinal
type and others don't].

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#75419

On 11/8/2015 1:37 PM, Malcolm McLean wrote:
> On Sunday, November 8, 2015 at 6:57:43 PM UTC, Martin Shobe wrote:
>>
>>> So there we've got an example of what you consider to be a real negative
>>> quantity. Temperature is "really" on a scale with absolute zero
>>> being the maximum, and everything else -X below it.
>>
>> That doesn't follow from what I said. I said you *could* treat
>> temperature that way. Anything that can be a positive-only can also be
>> negative-only and vice-versa.
>>
> That seems obviously wrong to me.
> A population can't be negative, surely? It's "really" positive.

In a sense, it's really positive, but that doesn't prevent one from 
treating what would have been the minimum population as the maximum and 
all remaining populations as negative.

> Also surface area. If we hold that the area of the Earth is
> negative, we'd have to say that the radius is imaginary. It's
> not clear to me that that's a workable system of notation.

Obviously, the formulas describing the relationships are different.

Martin Shobe

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