"joe dees" <joedees@bellsouth.net> writes:
> >Why would animals die, then?
> >
> Birth can only coexist with death in a world of finite room and
>resources populated by spacetime occupying and matter/energy consuming
>lifeforms.
Actually, death is a natural result of existing as metastable systems in a world with thermal fluctuations; sooner or later a large fluctuation is going to destabilize any system. Of course, this time might be extremely long, it is only relevant to show that death is deducible from our kind of physics.
Note that there is no a priori reason why all available matter/energy flows couldn't be converted into immortal static lifeforms (modulo a slight turnover due to thermal fluctuations as above; it can be made as small as desired). However, this state is unlikely due to another aspect of thermodynamics, namely the increase of entropy. The universe moves from less probable states towards more probable.
However, the third law of thermodynamics is also the reason we have evolved: evolution *demands* some form of selection, and if entropy didn't increase individuals and species could always un-die and evolution would be impossible. Complex systems can only appear randomly (i.e. extremely rarely) in a reversible world, while in an irreversible world they can flourish.
Note that this doesn't mean "death is good", is just means that without selection processes we can't have evolution. Intelligent beings can improve themselves without dying, by letting "their thoughts die in their stead" - still selection, but this time among information patterns.
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y