 According to theory-theorists, the posits of folk psychology are simply the mental states that figure in our everyday psychological explanations. Theory-theorists maintain the (controversial) position that, as theoretical posits, these states are not directly observed, though they are thought to account for observable effects like overt behavior. Theory-theorists also claim that common-sense assigns a number of properties to these states, such as causal, semantic and qualitative features. For instance, the theory-theory claims common-sense assigns two sorts of properties to beliefs. First, there are various causal properties. Beliefs are the sort of states that are caused in certain specific circumstances, interact with other cognitive states in various ways, and come to generate various sorts of behavior, depending on the agent’s other desires and mental states. As functionalists have claimed, these causal roles appear to define our ordinary notion of belief and distinguish them from other types of mental states. Second, beliefs have  intentionality;  that is, they each express a proposition or are about a particular state of affairs. This inherent intentionality (also called “meaning”, “content”, and “semantic character”), is commonly regarded as something special about beliefs and other propositional attitudes. Moreover, as we will see below, it is also a popular target of eliminative materialists who challenge the propriety and explanatory value of beliefs.