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From: sa209@utb.shv.hb.se (Claes Andersson)
Subject: Re: "What is Life?"
Message-ID: <1995Feb9.225702.26598@gdunix.gd.chalmers.se>
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References: <3gma5j$85l@scapa.cs.ualberta.ca> <3gmo28$l6j@engnews2.Eng.Sun.COM> <1995Feb5.124922.28250@gdunix.gd.chalmers.se> <3h5sqg$9qt@engnews2.Eng.Sun.COM>
Date: Fri, 10 Feb 1995 05:16:20 GMT
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holtz@netcord.Eng.Sun.COM (Brian Holtz) wrote:
>In article <1995Feb5.124922.28250@gdunix.gd.chalmers.se>,
>Claes Andersson <sa209@utb.shv.hb.se> wrote:
>
>>I consider active entropy sinking to be the one and only life
>>characteristic that could be thought as a necessary trait of ALL
>>possible lifeforms
>
>No, there are other characterizations -- being distinct from
>one's environment,
Isn't that kind of fuzzy? Why would that go for all lifeforms?
I don't say it doesn't but it would be interesting to hear.

 changing over time -- that are also necessary

>corollaries of life.  And, like "entropy sinking", these corollaries
>are _also_ corollaries of non-living things like tornados.  In short,
>these corollaries of life do not help us define life.

 I propose that a tornado and a rock change over time and
is (subjectively) distinct from their environment but they lack
any self-maintaing mechanism. I refer, once again, to that a
tornado don't add any energy to its own system to keep it
going.


>
>> My usual objection: There is a fundamental differece between
>>a tornado and a tree.
>
>There is, but has little to do with maintained low entropy.

Haven't it? I think it has, really.

>
>>The tornado can be predicted to last a certain amount of time,
>
>So can a tree.

 Yes, you are right but why? Can it be predicted from an analysis
of what it's made of? A tornado would be much easier to predict
like that.

 Take a tree, remove the entropysinking mechanism: the life. Take
another tree that is identical to the first one. The dead tree will
ofcourse decay just as fast as one could expect but the living
tree, even though it is made of exactly the same thing will go
on living until it dies.


>
>>it doesn't have any mechanism to add
>>energy to its system.
>
>Sure it does.  A tornado continues as long as there are atmospheric
>gradients from which to extract energy.  A tree continues as long as
>there are photons from which to extract energy.
>
>>A tree just like any lifeform, comes in two
>>flavours: Alive and dead.
>
>Tornados live and die; their corpses are just consumed more quickly
>than those of trees.
>
>>Compare a virus and a tornado. They have one thing in common:
>>They do not actively contribute to their low entropy in any way. But
>
>You seem fixated on notions of activity and intention.

 Intention? An increasing complexity perhaps but not an intention.
Don't you see what I mean? It's called metabolism in known living
creatures. This is how it manages to keep the entropy low.

>
>>the virus is still somewhat more alive, or perhaps has a lower
>>entropy: it is created in a way that allows it to stay in its low
>>entropy state for quite a time but that's nothing more really than
>>that stainless steel
>
>Bingo.  By your definition, tornados are as alive as trees, and
>viruses are as dead as steel.

No,no,no,no,no... You still don't understand what I mean... Viruses
are as dead as steel, I agree but tornadoes are also dead per my
definition. I've written this many times and I'll write it once again:

If a tornado would metabolize something (like what it sucks up or something)
to maintain its existance even after it would have "died" normally. Then it
would have been alive. It is very unlikely that we'll ever find such a
tornado since such abilities takes evolution to emerge. But if we found
one anyway, that tornado would be alive even if it couldn't reproduce.


>
>>Those things you are talking about have a low entropy but they
>>aren't alive.
>
>They maintain a low entropy and thus meet your criterion for life, and
>yet you exempt them from being alive.  Inconsistent.

I refer to the above. It is not inconsitant in any way.


Claes Andersson. University of Bors. Sweden
