"The Uses of Not"

Architecture is as much about 'negative space' as it is about structured design. But I think I get confused by the term. I know it as the purposeful inversion of a substantial mass in order to demonstrate the amount and shape of the space it occupies. Does regular space get 'filled in' while this negation occurs? I think so. But don't we use a reflexive projection to space.. measuring scale, composition and function by how inhabitable it is to the human? Don't we want to just put ourselves into the space, even using fantasy or mind-magic if the environment is hazardous?

There are 2 Japanese words that can better develop the idea. Mu, which as interpreted by Robert M. Pirsig means to sort of "unask the question". And Ma, which delivers this choice scripting:

In Japanese, ma, the word for space, suggests interval. It is best described as a consciousness of place, not in the sense of an enclosed three-dimensional entity, but rather the simultaneous awareness of form and non-form deriving from an intensification of vision.

A question came up recently in rl, and seems entirely suitable here: How does a geode form? Here's one you can sit inside.