 A narrow content of a particular state is a content of that state that is completely determined by the individual’s intrinsic properties. An intrinsic property of an individual is a property that does not depend at all on the individual’s environment. For example, having a certain shape is, arguably, an intrinsic property of a particular penny; being in my pocket is not an intrinsic property of the penny. This is because the penny’s shape depends only on internal properties of the penny, whereas the fact that it is in my pocket depends on where it happens to be, which is an extrinsic property. The shape of the penny could not be different unless the penny itself were different in some way, but the penny could be exactly the way it is even if it were not in my pocket. Again, there could not be an exact duplicate of the penny that did not share its shape, but there could be an exact duplicate that was not in my pocket. Similarly, a narrow content of a belief or other mental state is a content that could not be different unless the subject who has the state were different in some intrinsic respect: no matter how different the individual’s environment were, the belief would have the same content it actually does. Again, a narrow content of an individual’s belief is a content that must be shared by any exact duplicate of the individual. (If some form of dualism is true, then the intrinsic properties of an individual may include properties that are not completely determined by the individual’s physical properties. In that case an “exact duplicate” must be understood to be an individual who shares all intrinsic nonphysical properties as well as physical ones.)