to this forced reflection, and after a moment or two confesses humbly to Philonous that he cannot in fact conceive the matter in question. Not all Berkeley's readers, it is to be noted, will be as speedily submissive as Hylas. Nevertheless, this frequent insistence on stopping to consider the real meaning of a term, and on thinking with one's own brain—instead of accepting outworn words and truths on the authority of tradition—is one of the best lessons to be learned from the youthful works of the good Bishop of Cloyne.
IV
Yet in spite of the fact that Berkeley is not in the first instance a philosopher, and in spite of the fact that he approached philosophy with a practical rather than a speculative intention, his name is indissolubly associated with one of the greatest philosophic discoveries of the eighteenth century: the definitive reduction of matter to spirit. The Cartesian dualism of matter and spirit had already been transformed by Malebranche into a sort of spiritual monism, in which matter little by little faded away; and Locke had already reduced secondary qualities to sensations, and the concepts of cause and substance to mere relationships between ideas. But it was
