 It is a traditional assumption among realists about mental representations that representational states come in two basic varieties (cf. Boghossian 1995). There are those, such as thoughts, that are composed of concepts and have no phenomenal (“what-it’s-like”) features (“qualia”), and those, such as sensations, which have phenomenal features but no conceptual constituents. (Nonconceptual content is usually defined as a kind of content that states of a creature lacking concepts might nonetheless  have.[1])  On this taxonomy, mental states can represent either in a way analogous to expressions of natural languages or in a way analogous to drawings, paintings, maps, photographs or movies. Perceptual states such as seeing that something is blue, are sometimes thought of as hybrid states, consisting of, for example, a non-conceptual sensory experience and a belief, or some more integrated compound of conceptual and non-conceptual elements. (There is an extensive literature on the representational content of perceptual experience. See the entry on the  contents of perception.)