No words in English are shorter than I and few, if any, play a more fundamental role in language and thought. In Understanding I : Thought and Language Jose Luis Bermudez continues his longstanding work on the self and self-consciousness. Bermudez develops a model of how language-users understand sentences involving the first person pronoun I . This model illuminates the unique psychological role that self-conscious thoughts (typically expressed using I ) play in action and thought - a unique role often summarized by describing I as an essential indexical. The book opens with an argument directly supporting the indispensability of
I -thoughts in explaining action. After motivating a broadly Fregean approach linguistic understanding it critically examines Frege’s own remarks on I as well as the Fregean account offered by Gareth Evans. The main part of the book develops an account of the sense of I that explains a cluster of related phenomena, including essential indexicality, immunity to error through misidentification, the shareability of I -thoughts, the relation between I and you , and the role of autobiographical memory in self-consciousness.