Lexical predicates do substitute in fine-grained attitudes

Abstract

Let {'is a woodchuck', 'is a groundhog'} be a pair of synonymous lexical predicates. Are they intersubstitutable within a fine-grained attitude ascription without affecting either the truth-value of the ascription or the content of the attitude? I will show that synonymy is sufficient to preserve substitutability within any non-quotational context. Only this requires that substitution is executed within a semantics that observes semantic and epistemic transparency also in contexts such as hyperintensional belief reports. I will develop my argument within Transparent Intensional Logic. I use my pro-substitution claim to argue against one wrong reason for fine-graining, which introduces logical distinctions without semantic differences.