AbstractMaterialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature isintentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature isphenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state.WIREs Cogn Sci2012, 3:281–292. doi: 10.1002/wcs.1174This article is categorized under:Philosophy > Consciousness