>>6166
Or another possibility, that "physical materia" and "spirit materia" are only differentiated by how they happen to relate to other objects in the environment rather than the speed of the substance. So an object bearing the same "existential signature" as the viewer would be perceived as a regular object. While a differing relationship in existential signature might be an "invisible object" or a "thought". Or perhaps this would result from the signature corresponding to the viewer's 'mind' rather than 'body'. And an entirely incompatible set of existential signatures may result in two objects being "nonexistent" to one another.