Goal pillar

One required end-state that, together with the others, would make the master question plausible.

Pillars are architecture-neutral and as mutually exclusive and jointly exhaustive as the engine can make them. They are found by inverse failure analysis: list the catastrophic failures, cluster them, and invert each cluster into the healthy steady state that must hold. A pillar title must name a mechanism of failure, not an anatomical subsystem; a title that could be a textbook chapter is rejected. At least one pillar must be cross-cutting, addressing a systemic failure not obvious from anatomy. Each pillar carries a role: failure mechanism, or the one reserved identification pillar.

Note the two uses of "pillar": a goal pillar is a required end-state on the goal side; a scientific pillar is a piece of established science on the reality side.