To be alive does not necessarily mean to be conscious....or at least what we as humans understand as consciousness.
If not consciousness, maybe metabolism characterizes life.
"A singular characteristic of life is that at two moments in time that are sufficiently far apart, its matter cannot be the same; this means, conversely, if the material content is indeed identical at two different moments in time, then we are dealing with an organism that has stopped living and is dead."
But if the essence of what is life is defined as a process of change, so might other phenomena come under the definition...like, a wave.
But a wave is not really alive. So what is it that makes something alive?
"the point of life itself"?
...maybe "its...self-centered individuality, being for itself and in contraposition to all the rest of the world, with an essential boundary dividing 'inside' and 'outside.'"
All from John Stewart, Olivier Gapenne and Ezequiel A. Di Paolo, Enaction: Toward a New Paradigm for Cognotive Science (Cambridge: MIT Press, 2010).
