We don’t even have a good grasp on what life is! Try to get an explanation of why a living thing is alive, but when it dies despite having the same observable material condition its corpse is not alive. I’ve yet to hear anything beyond the most obvious begging of the question; it’s always some variation on living things are alive because they have life processes and nonliving things aren’t because they don’t. And what’s a life process? Well it’s a process that occurs in living things of course.