of the entity signaled. That is, the entities are 'likenesses' in some sense." Index: a sign in which "the occurrence of a sign vehicle token bears a connection of understood spatio-temporal contiguity to the occurrence of the entity signaled. That is, the presence of some entity is perceived to be signaled in the context of communication incorporating the sign vehicle." Symbol: the residual class, a sign which is not related to its object by virtue of bearing some qualitative likeness to it, nor by virtue of co-occurring with it in some contextual framework. These "form the class of 'arbitrary' signs traditionally spoken of as the fundamental kind of linguistic entity. Sign vehicle and entity signaled are related through the bond of a semantico-referential meaning" which permits them to be used to refer to any member of a whole class or category of entities. Silverstein observes that multiple signs may share the same sign-vehicle. For instance, as mentioned, linguistic signs as traditionally understood are symbols, and analyzed in terms of their contribution to reference and predication, since they arbitrarily denote a whole class of possible objects of reference by virtue of their semantic meanings. But in a trivial sense each linguistic sign token (word or expression spoken in an actual context of use) also functions iconically, since it is an icon of its type in the code (grammar) of the language. It also functions indexically, by indexing its symbol type, since its use in context presupposes that such a type exists in the semantico-referential grammar in use in the communicative situation (grammar is thus understood as an element of the context of communication). So icon, index and symbol are not mutually exclusive categories—indeed, Silverstein argues, they are to be understood as distinct modes of semiotic function, which may be overlaid on a single sign-vehicle. This entails that one sign-vehicle may function in multiple semiotic modes simultaneously. This observation is the key to understanding deixis, traditionally a difficult problem for semantic theory. Referential indexicality (deixis) In linguistic anthropology, deixis is defined as referential indexicality—that is, morphemes or strings of morphemes, generally organized into closed paradigmatic sets, which function to "individuate or single out objects of reference or address in terms of their relation to the current interactive context in which the utterance occurs.". Deictic expressions are thus distinguished, on the one hand, from standard denotational categories such as common nouns, which potentially