The focus of this book is a single question: how does one know one’s own mental states? For instance, how do you determine what you’re feeling or thinking right now? How do you identify your own beliefs and desires? There is little doubt that we do know some of our mental states. Statements like “I feel a tickle,” “I’m thinking about lemonade,” and “I believe that it’s sunny today” sometimes express knowledge. But philosophers disagree about the nature of such knowledge. These disagreements have important consequences for larger disputes about knowledge and the mind. In the examples just given, knowledge of a mental state involves

registering the state as one’s own: e.g. recognizing that I am feeling a tickle. This raises another set of questions, concerning how one conceives of oneself and distinguishes oneself from other things. Most philosophers agree that each of us is aware of an “I” or self, though some deny that there are such things as selves. But there is deep disagreement about how such awareness is achieved and what it consists in. This controversy about self-awareness plays a pivotal role in shaping theories about the self and its relation to the world.