<p>There is a class of expressions which are perceived as ‘ungrammatical’ not because they are syntactically ill-formed but because they have interpretations which are informationally trivial. Triviality-driven unacceptability constrains the distribution of determiners, modals, attitude verbs, exhaustifiers, approximatives, among many other classes of logical terms. At the same time, many superficial tautologies and contradictions—pre-theoretically, the clearest examples of trivial expressions—are judged to be perfectly acceptable. This paper discusses two promising yet fundamentally opposed attempts to model triviality-driven unacceptability without over-generating ‘ungrammaticality’ judgments. One approach combines the ‘Logicality’ view that the language system includes a deductive-inferential system (DS) that automatically identifies and filters out expressions with trivial interpretations, with the hypothesis that the DS runs on ‘modulated logical forms’, i.e., structures where all content-based terms and variables are subject to meaning-modulation operations. The other approach downplays Logicality and tries to reduce triviality-driven unacceptability to familiar kinds of pragmatic infelicities. The Logicality-based approach, I argue, is superior to the most sophisticated attempts to treat triviality-driven unacceptability as a species of pragmatic infelicity. This result suggests that our purely linguistic and logical competences are deeply intertwined, and sheds new light on the division of labor between syntax, semantics and pragmatics.</p>