Definition of Life

Rafael N Szeinfeld szeinfel at FOX.CCE.USP.BR
Wed Feb 9 06:56:50 EST 1994



On 9 Feb 1994, Julian Blanc wrote:

> The best definition I heard was given by John Maynard Smith. A living 
> thing must a physical dissipative structure having the following 
> characteristics:
> 
> 
> 	- Variation 
> 	- Reproduction
> 	- Heredity
> 
> This definition excludes fire, vortexes, planets, replicating clay crystals, 
> priests and cellular automata. It includes, however, free replicating 
> informational molecules such as nucleic acids, which is pretty neat. 
> 
> Julian Blanc
> 
> 
> 
	Hi,
	I would like if you explain better what you mean with variation 
and as I suppose, how  these requeriment excludes crystal growth. Indeed, 
a DNA molecule can not be classified as a living thing.
	A crazy idea comes to my mind now:
	What if we say that life has nothing special than a crystal (for
exemple) has ? It's just another form of organization of molecules. 
Sounds strange ? let's discuss it!

Rafael Najmanovich Szeinfeld





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