Because either a thing has no measurable effect on our reality and is thus both unknowable and irrelevant, or it has a measurable effect on our reality and then

Because either a thing has no measurable effect on our reality and is thus both unknowable and irrelevant, or it has a measurable effect on our reality and then this effects exists in virtue of a kind of relation that can be described, maybe. What is one can be unified in theory as it is in practice. What is two doesn't have to, and we will never try to because we don't know it.