According to H-N. Castañeda, a guise - the very thin individual which lies at the bottom of the ontological furniture of the world - is indifferent to existence in a Meinongian way, in the sense that it remains the same whether it exists or not. Moreover, its existence does not alter its intentional character, as it is the very same individual which is thought of regardless of its being real or not1. In what follows, I will attempt to show that (...) with regards to guises both theses are illegitimate, unless one introduces the notion of an existentially-conditioned property as a counterfactual property which a guise has prior to its actual existence. To do so means to work out an amendment to Castañeda's Guise Theory, as the doctrine which supports his main ontological assumptions. (shrink)