Inference in Action Johan van Benthem Abstract: Substructural logics describe varieties of inference that humans can engage in within specific settings. One such setting are dynamic state transitions when processing information. We recall the complete set of (non-monotonic, non-commutative, non-contractive) structural rules for dynamic 'update-to-test inference', and the proof of its completeness for the specific area of epistemic update. Then we broaden our discussion to make a case that polymodal logic itself is a good substructural theory of 'plan inference'. Next, we turn to concrete model-changing notions of inference, as proposed by Lindstroem and Barwise & van Benthem, and discuss their connection with model-theoretic results on interpolation and conservative extension. Keywords: structural rules; dynamic logic; epistemic update; ; representation; interpolation; model change