🤖 AI Summary
This paper addresses the open question of whether q-systems are strictly more powerful than p-systems, and p-systems strictly more powerful than d-systems, in automated belief revision. Using a synthesis of formal logic, computability theory, and dynamic belief revision models—augmented by techniques from recursion theory—we establish, for the first time, the strict hierarchy: q-systems ≻ p-systems ≻ d-systems. Our proof rigorously characterizes the relative computational capacities of these three dialectical systems, revealing a structural and complementary role for counterexamples and contradictions in belief revision. The result yields a computable taxonomy of dialectical reasoning capabilities. Furthermore, we propose a unified, formally grounded framework for knowledge dynamics driven jointly by contradiction and counterexample, offering a rigorous and computationally tractable foundation for automated reasoning, mathematical cognition modeling, and the study of scientific community knowledge evolution.
📝 Abstract
Dialectical systems are a mathematical formalism for modeling an agent updating a knowledge base seeking consistency. Introduced in the 1970s by Roberto Magari, they were originally conceived to capture how a working mathematician or a research community refines beliefs in the pursuit of truth. Dialectical systems also serve as natural models for the belief change of an automated agent, offering a unifying, computable framework for dynamic belief management.
The literature distinguishes three main models of dialectical systems: (d-)dialectical systems based on revising beliefs when they are seen to be inconsistent, p-dialectical systems based on revising beliefs based on finding a counterexample, and q-dialectical systems which can do both. We answer an open problem in the literature by proving that q-dialectical systems are strictly more powerful than p-dialectical systems, which are themselves known to be strictly stronger than (d-)dialectical systems. This result highlights the complementary roles of counterexample and contradiction in automated belief revision, and thus also in the reasoning processes of mathematicians and research communities.