ABSTRACT
In contemporary philosophy the focus of study is the use and interpretation of language. To study scientific inquiry is to study the language of science and how it is used; to study legal decision-making is to study the language used in applying laws; to study aesthetic expression is to study the symbolic forms for this expression; and so it is for every human activity. For philosophy seeks to understand the nature of thought, and to think is to use and interpret language, sometimes as it is publicly expressed by ourselves and others, sometimes in the form of what Plato calls in the Phaedo the 'inner dialogue of the soul with itself' where public expression is suppressed or delayed. If we had special introspective powers by which we could directly intuit the nature of our thought processes, then language might playa less central role in philosophical investigations. But we have no such powers, and previous attempts to describe directly these processes and their contents through such terms as 'concept', 'idea', 'sense data', etc. can be shown to be in fact importing distinctions derived from language. Hence the shift instituted at the end of the nineteenth century by Frege and Peirce from a conception of philosophy as the study of psychological processes to one concentrating on the description and analysis of linguistic expressions.
