It would be easy to define life as that which is built from subentities bounded by fatty membranes and containing many proteins and nucleic acids on the inside. But many biologists have found this definition to be unsatisfying because it does not mention what they take to be the essential mark of life, and that is the purposive teleology that life apparently exhibits. Of course complex human artifacts are also teleological, but the purposiveness of human artifacts can be accounted for through human teleology. That is, humans "inject" teleology into their artifacts; so the purposiveness of artifacts is said to be "derived", and not "intrinsic". Organisms, on the other, have an "original" teleologicality that both artifacts and nonartificial physical systems do not possess.

So if you really want to break down the life/nonlife distinction, the best strategy would be to show that even "mere" physical systems also exhibit a certain teleologicality or functional organization. This could be accomplished by showing that the physical systems we actually observe have undergone a history of natural selection of sorts. Thus, you could say that even mere physical systems are functionally organized around the intrinsic value of physical persistence.