This dissertation explores finiteness and its role in licensing nominative case and subject case more broadly. It examines data from Turkish and other Turkic languages to argue that (1) the feature licensing nominative case in finite clauses in Turkish is a complex feature consisting of mood on the complementizer and epistemic modality on finiteness, marking finiteness, and (2) the feature licensing genitive or accusative case on subjects of non-finite clauses licenses a nominal feature on D/K (determiner/case) for genitive or a verbal feature on v for accusative. The analysis predicts a lack of epistemic modality or mood in exceptional case marking constructions. A key theoretical implication is the dis