 Representationalism, as presented so far, is an identity thesis with respect to qualia: qualia are supposedly one and the same as certain representational contents. Sometimes it is held instead that qualia are one and the same as certain representational properties of experiences (or properties represented in experiences); and sometimes it is is argued that these representational properties are themselves irreducible (Siewert 1998). There is also a weaker version of representationalism, according to which it is metaphysically necessary that experiences exactly alike with respect to their representational contents are exactly alike with respect to their qualia. Obviously, this supervenience thesis leaves open the further question as to the essential nature of qualia.