I guess mean arbitrary in the sense that being born as a human is kinda arbitrary, in the sense that individual human perspectives themselves are arbitrary amongst the vast range of possible ways to experience or perceive, both human and beyond human.
Well and also in the sense that it takes some pretty arbitrary decisions to distinguish living from nonliving.
I don't mean that these distinctions are useless or unimportant, just that for the most part they may not be all that fundamental... You end up drawing lines in the sand.
For example, are you gonna exclude viruses from the tree of life? Why? Because viruses don't have any known local macroscopic motility? Because they rely too heavily on their environment ("host") to reproduce? Those are summaries of the arguments I've heard against viruses being alive, and imo they're pretty arbitrary.
On the other hand, viruses reproduce and are subject to selective pressures, as are most phenomena with a lifecycle and an external environment. So then if you include viruses are you gonna include RNA? What about reactions, e.g. combustion? Are these alive? Well then and what about consumer product/producer systems? Don't they have lifecycles of their own? Some feedback loops that cause selective pressures? Environments to survive and reproduce in?
It's fuzzy.
A lot of rational, materialistic categorizations of living vs unliving look to me like hunches based on assumptions about motility or consciousness, and might as well be reframed as "does it move?" or "can I communicate with it?" or "does it see me?"
Lynn Margulis and Dorion Sagan wrote a nice essay called "the uncut self" that's really great and related to this in my view. It's all about where the tendency to draw boundaries around "individual selves" when looking at living systems, boundaries that might not be so fixed or obvious when you look carefully.