What is life?
Everyone must at some time have had a stab at defining life, so here’s mine…..
A question that scientists and philosophers have struggled with for some millennia is what distinguishes living from non-living matter. Many different definitions of life have been proposed but one characteristic seems evident, living matter has the capacity to make copies of itself while by dissipating energy. This is unique among all other physical phenomena we know. But it is more than just copying, its bad copying in a resource limited world. When living systems copy themselves they do so imperfectly. This means that the copies (the progeny) tend to have slightly different characteristics from the parents. This behavior leads to evolution and in a world of finite resources, selection. That is:
“A system that is alive is something that makes an imperfect copy of itself as it dissipates energy”
This definition eliminates things like crystals and self organized structures like Bernard cells, However it does include things like viruses, bacteria, people and perhaps more controversially many alife forms such as Avida.