The very special vigour and attraction of Ryle's philosophical work are due to the highly personal way in which it is written as well as to the force of the ideas and reasonings it contains. A notable source of its vitality is the resolution with which he avoids the ordinary devices of scholarly exposition. Other philosophers are seldom mentioned by name and even less often quoted. The positions criticised are not precisely and historically identified. As a result his books and articles are delightfully unencumbered by footnotes. He will, furthermore, go to some trouble to exclude from his work the usual technical vocabulary of philosophical debate. Sense-data, universals, pure egos, and so forth are mentioned from time to time but only with an explicit cautionary apparatus f initial capitals and inverted commas that has the effect of assimilating them to the Great Boyg, the Will-o"-the-Wisp, and Uncle Tom Cobleigh.