Abstract. We show that under the assumptions of Spectrum Exchangeability and Language Invariance the so called Only Rule, a principle of instantial relevance previously know for unary (i.e. classical) Carnapian Inductive Logic, also holds in Polyadic Inductive Logic. Key words. Instantial Relevance, Spectrum Exchangeability, Inductive Logic, Probability Logic, Uncertain Reasoning.
Jürgen Landes, Jeff B. Paris, Alena Vencovsk&