At/on/by

From eg

This living ontology pattern helps distinct roles to separate point of view and avoid GEVAD. The use of prepositions (at, on and by) indicate very fundamental distinctions.

Asking and answering where/when/who is useful and necessary, but the answer is only the object. All facts are assessed at/on/by a particular subject. Thus to keep body/subject/object separate requires separating s/he who asks from the observer from the answerer. Each subject only perceives a limited range of where, when, and who, and knowing where someone is at, what date it was on, and who it was by, is the only way to avoid relying on generalized repute systems, either positive or negative. This is also called the witness pattern.