Abstract
It is fitting to begin this book on intuitionistic type theory by putting the subject matter into perspective. The purpose of this chapter is to relate intuitionistic type theory to the old dream of a lingua characteristica. The line of thought which leads to the lingua characteristica can be briefly summarized as follows. Man thinks about thing and expresses his thoughts in word: this leads to the threefold correspondence discussed in the first section. Based on this correspondence, the acts of the mind, or the thoughts themselves, are analysed and divided in the second section. The third section treats of a theory of meaning according to which the complex is understood by synthesizing, as it were, the meanings of its parts. The fourth and last section of this chapter gives an account of the history of the lingua characteristica.