The Cambridge History of English and American Literature in 18 Volumes (1907–21). Volume IX. From Steele and Addison to Pope and Swift. XI. Berkeley and Contemporary Philosophy. § 8. His Common-place Book. Berkeley stood at a parting of the ways in thought, though he was hardly conscious of their divergence. On the one hand, his principles that all knowledge is of ideas, and that all ideas are of one or other of the three kinds enumerated by him, lead to a view which excludes from knowledge not only material substance, but mind, also, and the reign of law in nature. At times, especially in his Common-place Book, he seems on the brink of drawing this conclusion, and thus of anticipating Hume. Afterwards, he sees it only as something to be guarded against. He could not think of the idea as, so to speak, self-supporting. supporting. It exists only in so far as it is “in the mind”: mind is the true reality, the only agency; ideas exist only in minds, finite or infinite; and the laws of nature are the order in which ideas are produced in us by the infinite Mind. Spiritual agency, spiritual reality, is thus his fundamental thought; and, in Siris, the last of his philosophical works, this thought emerges from the midst of reflections on empirical medicine and old-fashioned physiology. No longer dominated by the Lockean heritage of the sensitive origin of knowledge, his idealism is assimilated to the Platonic; the work is full of comments on Neoplatonic writers, ancient and modern; and there is an absence of the simplicity and clearness of his earlier writings; systematic development of his theory is still absent; but there is hardly a page without remarks of pregnant insight, and he is everywhere loyal to the vision of truth with which his career opened.   10