Conceptions of fact, has become a Babel in which even so staple a construction as he is good can be found described in nine different ways. The situation has indeed called out, both here and abroad, a propaganda of reform; and a British Joint Committee has already offered a scheme of harmonised nomenclature. But the discussions upon this movement make it increasingly clear that questions of terminology must be approached through a fresh appraisal of the notions that our terms presuppose. Such an appraisal this little book aims to formulate. I address it to teachers and serious learners in both classical and modern language-study, who would follow the ideas they work with into their back ground of psychology and logic.