 As McGinn (1977), and Burge (1979), have pointed out, this claim can be extended to the content of propositional attitudes. In ascribing a propositional attitude—such as a thought, belief, desire—to a person, we use a “that”-construction, followed by an embedded sentence. The sentence is commonly thought to express the content of the propositional attitude: that is, the meaning of the sentence is identical with the content of the propositional attitude. Therefore, if the sentences expressed by you and your twin have different meanings, it is difficult to avoid the conclusion that the contents of your thoughts, beliefs and desires also vary. However, beliefs, and other propositional attitudes are individuated by their contents. The belief that grass is green is a different belief from the belief that snow is white because their contents are different. Therefore, if the contents of the beliefs had by you and your twin are different, then so too are your beliefs.