The problem of subjective is different, because while we might be able to get to a point of being able to say it can't affect anything, pretty much by definition we can't experience another entity's subjective experience or lack thereof.

Even if we were to e.g. identify some field that seemed to coincide with entities reporting a subjective experience, we wouldn't have a way of determining if they truly do, or just act as if they do, nor is it clear such entities would be able to report the difference.

As it is, we struggle to quantify even much more basic differences in experience that we can introspect. E.g. I have aphantasia - I don't see things in my minds eye - and I regularly come across people who insists both that can't be true, and that it can't be true that others see things. And some of the people I've spoken to who insist aphantasia isn't real clearly has it based on digging into their thinking about it.

Even at that level we rely on trusting people's claims about their introspection - we don't know, we assume based on testimony.

Worth keeping in mind, yes, but biological processes are readily observable whereas subjective mental phenomena are... not. Everything about them is inaccessible and frankly unfalsifiable except for the fact that they're the bedrock of all the rest of our observations. Not directly comparable.

Anyway, further reading: https://en.wikipedia.org/wiki/Vitalism I was in fact looking this up recently for fiction-writing purposes.