[2603.28371] Coherent Without Grounding, Grounded Without Success: Observability and Epistemic Failure

Computer Science > Computers and Society arXiv:2603.28371 (cs) [Submitted on 30 Mar 2026] Title:Coherent Without Grounding, Grounded Without Success: Observability and Epistemic Failure Authors:Camilo Chacón Sartori View a PDF of the paper titled Coherent Without Grounding, Grounded Without Success: Observability and Epistemic Failure, by Camilo Chac\'on Sartori View PDF HTML (experimental) Abstract:When an agent can articulate why something works, we typically take this as evidence of genuine understanding. This presupposes that effective action and correct explanation covary, and that coherent explanation reliably signals both. I argue that this assumption fails for contemporary Large Language Models (LLMs). I introduce what I call the Bidirectional Coherence Paradox: competence and grounding not only dissociate but invert across epistemic conditions. In low-observability domains, LLMs often act successfully while misidentifying the mechanisms that produce their success. In high-observability domains, they frequently generate explanations that accurately track observable causal structure yet fail to translate those diagnoses into effective intervention. In both cases, explanatory coherence remains intact, obscuring the underlying dissociation. Drawing on experiments in compiler optimization and hyperparameter tuning, I develop the Epistemic Triangle, a model of how priors, signals, and domain knowledge interact under varying observability. The results suggest that neithe...