This article offers the first systematic investigation of the linguistic forms in which Kant expresses his transcendental idealism since Gerold Prauss’ seminal book Kant und das Problem der Dinge an sich. It is argued that Prauss’ own argument for the claim that ‘in itself’ is an adverbial expression that standardly modifies verbs of philosophical reflection is flawed and that there is hence very poor exegetical evidence for so-called ‘methodological two-aspect’ interpretations of Kant’s transcendental idealism. A comprehensive investigation of Kant’s adverbial uses of ‘in itself’ rather reveals that there are various groups of verbs that ‘in itself’ modifies, which can more or less all be reduced to a standard use in which ‘in itself’ modifies verbs of predicative being such as the copula. It is also discussed how these findings can be accommodated by the two main alternative kinds of interpretations, that is, two-object and ontological two-aspect interpretations.
