That is a real problem though. Many things you cannot define because their bounds are indefinite. To define those things requires knowing the bounds. It's much simpler to accept our limitations in language and cognition because it removes those artifical boundaries when connecting physics to metaphysics. We only need to describe things when they matter.

Then there are things you can very solidly define but never know what they are. We can describe physics, and their applications, but when connecting metaphysical effects down to the constituent quantum processes the whole is unknown. We aren't sensible enough.

The truly wholesome perspective is from outside the universe.