This note reports preliminary results from an ongoing effort to place ECL₃Q — a three-valued epistemic causal logic with an ontological (not epistemic) third value U, developed independently in Paper I — inside a more general classificatory framework for many-valued and non-classical logics. The guiding question is not whether ECL₃Q is novel, but how many independently developed logical systems can be recovered as special cases of a single abstract level tree, following an extension-rather-than-replacement principle (in analogy to Newtonian mechanics as a limiting case of relativity). Within this tree, K3, Ł3, Bochvar’s internal connectives, LP, FDE, intuitionistic propositional logic, de Vries’ fuzzy/quantum hierarchy, and supervaluationism are all recovered as special cases; ECL₃Q occupies one further branch (Level 3), distinguished by an irreversible collapse dynamics. The root of the tree separates two architectures — Nmatrix-based (non-deterministic multifunctions, with truth-functional determinism as a special case) and precisificational — and we report two universal statements holding across this entire space, independent of any specific branch. The framework is formalized institution-theoretically; we report a completeness result for a restricted fragment of ECL₃Q, a matching incompleteness result for the full language that we present as a counterexample to Diaconescu’s (2017) generic compactness pattern for stratified institutions — based on secondary-source review of the abstract, not verified against full text — and a closed negative result on model amalgamation for the non-deterministic branch. This is a work-in-progress, informal preprint, fully independent of Paper I (currently under review at the Journal of Logic and Computation), with no citation dependency in either direction. Open points are stated explicitly rather than concealed.
Markus Karl Bauernfeind (2026) studied this question.