[e2e] [SPAM] Re: a means to an end

touch@ISI.EDU touch at ISI.EDU
Wed Nov 12 16:34:13 PST 2008

Quoting "David P. Reed" <dpreed at reed.com>:

> You should be careful.  If the mole of gas is embedded in a larger 
> system, its information is not separable from the larger system's 
> information because there is no isolation.

If you're talking about its temperature, that is defined as its average kinetic
energy, which has no relationship to the environment in which it exists.

However, intrinsic values like temperature are not in of themselves
"information"; e.g., the mass of an electron is not "information" per se, but
it can be information to an entity to whom that value is not known. Information
is defined over a set of possible states, as the difference between the number
of actual states vs. the number of possible. In this case, it's the number of
possible temperatures vs. the actual temperature. Again, none of this is
related to the system in which the gas resides.

That's not to say that there are not measurements that are related to the
environment of the system, but this isn't one of them. Or are you running
towards the Liouville Theorem, regarding aggregate information and its
conservation in a closed system?

Why, however, is this relevant? 


> Joe Touch wrote:
> > Hash: SHA1
> >
> >
> >
> > David P. Reed wrote:
> >   
> >> No, information is not the uncertainty in the outcome of an event (not
> >> least because that puts information as a "future" thing).  It's related
> >> to the number of possible states of a system as a whole.   Decomposing
> >> the state of a system into the state of parts (needed to assign a
> >> location to some piece of information) must be done carefully, because
> >> the states of parts may have invariant relationships, which reduce the
> >> number of states, and create the illusion of information where there is
> >> none.
> >>     
> >
> > There are numerous definitions of the term. Let's use your proposed one:
> >
> > 	"related to the number of possible states of a system"
> >
> > Both the system and the states are represented physically, and thus have
> > a location.
> >
> >   
> >> E.g.: the states of atoms that make up a one-bit storage cell typically
> >> are highly correlated.  Thus the cell contains a single bit of
> >> information, whereas the individual atoms contain no bits (or more
> >> properly, they contain contingent information, of the sort that the
> >> "majority" talks about).
> >>
> >> Similarly, the "temperature" of a mole of gas expresses a bounded number
> >> of bits of information, and that information is neither an event nor a
> >> place, and is not independent of the "pressure" and "volume" of the gas,
> >> each of which is dependent on the other.
> >>     
> >
> > The gas has a location. I never said that a bit correlated to an atom or
> > a *point* in space.
> >
> > Joe
> > Version: GnuPG v1.4.9 (MingW32)
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> >   

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