ENThis article considers the kind of information that is relevant for determining argument structure, and how this information is encoded syntactically. The approach I take here, anchored largely in Reinhart’s (2002) Theta System, contributes both to the widely discussed question of underspecification in argument structure and to our understanding of a specific construction in Lithuanian, the Transitive Impersonal. The Transitive Impersonal is a construction in which accusative appears on a predicate’s Theme argument in the absence of a higher Agent. The Transitive Impersonal is one alternate in a systematic impersonalization alternation, in which the source of causation is crucially not fixed in the lexicon, but rather admits variable realization, either as a canonical (nominative) Agent or a non-volitional Causer, the latter marked by an oblique relation or not realized overtly in the syntax at all, but interpreted semantically. I advance a causative theory of accusative for which I adduce independent evidence from the Icelandic Fate Construction. [From the publication]