More on 2nd Law etc

X-Message-Number: 28641
From: 
Date: Mon, 6 Nov 2006 09:58:44 EST
Subject: More on 2nd Law etc

To Chris Manning's  questions:
 
>Did you mean, 'we' as in the human race, i.e. the human race could be  
>eventually distributed over large volumes (e.g. colonies on Mars, etc.)?  Or 
>did you mean that an individual consciousness might be widely  distributed?

The latter.
 
>Blowflies are particularly annoying. They fly around everywhere,  seemingly 
>at random. (I suppose it's not really random but it seems that  way to me.) 
I 
>try to avoid using fly spray. Instead, I open the window  and wait until the 
>blowfly 'randomly' flies out, then I close the window  again.

>It occurred to me recently that this procedure might have some  implications 
>for the Second Law and related issues.

This is like Maxwell's Demon. Doesn't work overall.However, this is  
essentially the 
same as my example of organizing a room. You have decreased disorder of 
a particular kind, while not (apparently) having any effect on the rate of  
change of
entropy in the rest of the world, including your brain. 
 
>> (4) Consider a person deliberately creating order, say by  organizing a 
>> room.
> >Is there any countervailing chsnge  that would imply overall decrease in
> >order? Not that I can see.  Metabolic processes in the person might result 
>> in his
>>  increase in entropy, but that does not seem related to the particular  
>> activity
>> he is engaged in.


>The person is  not a closed system. 
 
Maybe the universe isn't either, as many cosmologists seem to think.
 
>During the time you spend organising your 
>room, hasn't the  sun's entropy increased by many times more than the 
>decrease in entropy  of your room? And you would not be in a position to 
organise your 
>room  if the sun's entropy were not increasing.

My point was that the increase in entropy of the rest of the universe (you 
and everything except the room) does not seem contingent on changes 
in the room that you have organized. In other words, you can make 
choices, resulting in greater or lesser order in the room itself, which  will 
(as far as I can see) not affect the entropy of the rest of the universe, 
including your brain. 
 
>(I'm assuming we could come up with a 
>suitable definition of  the word 'entropy' that could be applied to the 
>contents of your room.) 
 
Yes, I glossed over the difference between entropy and thermodynamics. 
The Second Law initially referred to a very narrow context, heat engines, 
and essentially said merely that, when you transfer heat from a source 
to a sink, only a portion of that heat can be transformed  into useful work. 
More 
generally, as in statistical mechanics, entropy is proportional to the 
probability (or logarithm of the probability) of a state. But  definitions
 of "state" and probabilities can be tricky.
 
R.E.
In a message dated 11/6/2006 5:01:33 AM Eastern Standard Time,  
 writes:

>  Message #28621
> From: 
> Date: Fri, 3 Nov 2006  10:19:54 EST
> Subject: Re: CryoNet #28616 - #28620
>
>  Chris Manning wrote in part:
>
>>I suppose what this [declining  likelihood of death in a given time  frame]
> means in practice  >is that you would have to be
>>continually making your life safer  and eliminating anything that might
>>threaten it, by getting better  at predicting earthquakes, deflecting
>>bolides, maybe growing your  own food, etc.
>
>
> Mainly it means other things,  including
>
>>>Also, we could eventually be individually  distributed  over
>>> large volumes.


I wasn't sure  what you meant, and as a result I also wasn't sure how it 
related to the  'declining likelihood of death' issue.

Did you mean, 'we' as in the  human race, i.e. the human race could be 
eventually distributed over large  volumes (e.g. colonies on Mars, etc.)? Or 
did you mean that an individual  consciousness might be widely distributed?


>
>  Now,
>
>>>Also, the Second Law does not guarantee   eventual oblivion,
>>> for reasons I won't detail here unless  requested.
>
>>I  hereby request you to detail  them!
>
> OK, the Second Law refers to probabilities. In classical  physics, in a
> closed system, entropy (roughly disorder) TENDS toward a  maximum, which is 
> often
> interpreted to mean eventual "heat  death." BUT
>
> (1) we don't know if the universe or cosmos is  closed, and many 
> cosmologists
> currently think  not.
>
> (2)  Order and disorder do not always have agreed  definitions, and  many
> natural processes tend toward what most  would call order. For example, 
> the
> formation of galaxies and  stars and planets and life, and the formation of 
> mineral
>  deposits in the earth, and many other processes, would from our point of  
> view
> represent increasing order.
>
> (3) When in  some closed system maximum entropy is achieved, the only
> possible  change after that is a decrease of entropy or an increase in 
> order,  and
> subsequently there will be fluctuations with entropy increasing  for a 
> while and
> then decreasing for a while, with rare random  spurts of very low entropy.


Blowflies are particularly annoying.  They fly around everywhere, seemingly 
at random. (I suppose it's not  really random but it seems that way to me.) I 
try to avoid using fly  spray. Instead, I open the window and wait until the 
blowfly 'randomly'  flies out, then I close the window again.

It occurred to me recently  that this procedure might have some implications 
for the Second Law and  related issues.


>
> (4) Consider a person deliberately  creating order, say by organizing a 
> room.
> Is there any  countervailing chsnge that would imply overall decrease in
> order? Not  that I can see. Metabolic processes in the person might result 
> in  his
> increase in entropy, but that does not seem related to the  particular 
> activity
> he is engaged in.


The person  is not a closed system. During the time you spend organising your 
room,  hasn't the sun's entropy increased by many times more than the 
decrease in  entropy of your room? (I'm assuming we could come up with a 
suitable  definition of the word 'entropy' that could be applied to the 
contents of  your room.) And you would not be in a position to organise your 
room if  the sun's entropy were not increasing.

Correct me if I am wrong, as it  is many years since I studied physics. 

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