Comment by schiffern

If you dropped me off in vacuo (eg in deep space), I wouldn't meet the definition of "alive" either. But the fact that my life require a specific environment doesn't phase us or challenge our definition of life at all.

Not only do I need certain physical conditions (temperature, pressure, molecular gas composition, etc), but I also need to eat, so actually me being "alive" is dependent on specific biological conditions too. My Minimum Viable Environment actually includes other organisms, yet this doesn't challenge the fact that I'm defined as alive.

Certain parasites can only live or reproduce within another organism. This is even more extreme, but it still doesn't challenge our definition of them as being "alive."

This new organism requires a specific "environment," and that "environment" happens to be inside another organism. So what? We're totally un-phased by this requirement when it occurs in other examples.

Perhaps it's better to think of this not as a spectrum between alive and non-living, but as a hierarchy of how constrained (vs unconstrained) is the "environment" required to support life processes.