This paper establishes a formal proof that the six primary interrogatives - WHO, WHAT, WHERE, WHEN, HOW, and WHY - constitute a minimal necessary basis for primitive state-of-affairs inquiry. Working within Ciardelli's (2016) dependency framework for interrogative semantics, the proof establishes three properties: mutual independence (for each interrogative, complete answers to the remaining five are compatible with multiple distinct answers to the sixth), joint exhaustiveness (every primitive interrogative over a state of affairs requests one of six irreducible structural determinations, and no seventh category satisfying the primitivity criterion exists), and minimality (no member can be removed without losing coverage of at least one irreducible structural determination).
The proof is bounded to primitive state-of-affairs inquiry and does not claim universality over all possible formal systems. It establishes that the six interrogatives are not a conventional checklist or pedagogical tradition but the provably minimal necessary basis for the structural domain the Geometric Inquiry Theory (GIT) research program operates within. The paper situates the proof within three lines of GIT work it formally grounds: the Q-ISA structural measurement instrument, the Geometry of the Blind Spot, and the Formal Framework for Reasoning Stability Under Recursive Inquiry.