A possible definition of life.

Ian Clarke ianc at dai.ed.ac.uk
Sun Apr 20 10:44:57 EST 1997



> I have been reading about Artificial Life (studying for college) and have hit
> upon what I think could be a definition of life (at least on Earth). But I am
> neither arrogant enough nor stupid enough to believe that this has not been
> thought of before and there are probably good reasons why this is not a good
> definition. Please could someone explain to me why the age-old problem of
> defining life is not solved by:
> 
> "Life (on Earth) consists of all things built by DNA."

Because it is not a terribly useful definition, it is like saying that
computers are all things made of silicon - in that it is for the most part
true, but it is quite possible that someone will come up with a computer
that does not use silicon, and then the definition will no-longer be
valid.  IMHO a definition is only any use if you can use it to classify
things that have not yet been observed.  There is no good reason that life
does not exist on Earth which does not consist of DNA.  Wasn't the first
life based upon RNA anyway?

In any definition you must strive to be as broad as possible, while not
encompassing anything that clearly should not belong to the set you are
defining.

Ian.




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