With the emergence of the scientific study of the human mind itself, these critical questions have taken a more intriguing form in recent decades. Can human inquiry investigate its own nature? Can the scientific theory of language explain the richness of human expression? Can a science of the mind account for human experience? These probing questions on the scientific enterprise are usually addressed from the outside, as it were, by humanists and critical theorists. In these essays, they are examined from the inside by a philosopher whose primary academic work concerns the study of the human, linguistic mind. In that sense, the sceptical inquiry turns on itself.