Actually, it isn't. It's just applying the definitions of the words.
That's irrelevant, we are not talking about you, we are talking about science and reality. And yes, human science would end if all humans and all traces of our writings on science die, as would whatever have been all our concepts of what reality is. If you are asking about real reality, rather than our concept of reality, then you are talking nonsense, because the only thing we can have a conversation about is our concept of reality-- and that's not philosophy, it's fact.

I think what you are actually saying is that our concept of reality is connected with our ability to imagine something that exists outside of our imagining it. This model of reality works great, passes most of the tests we give it, and will be gone with us-- unless some nonhuman intelligence is also using it (which they likely are).