=Berkeley’s General Relation to Locke and Hume.= The growth of this English school from Locke to Hume is not difficult to understand or to remember. It is not so much a page in the history of metaphysics (the nature of reality) as in epistemology (the theory of knowledge). Locke asks, What can we know? And he replies to his own question, that we can know our “ideas.” At the same time he assumes the existence of a spiritual substance on the one side, and a material substance on the other. Neither of these is an idea, in the sense that it is an object of knowledge. The advance of Berkeley from Locke and of Hume from Berkeley was one of cancellation. Berkeley cancelled the material substance, because the material substance is not an idea. Hume then consistently enough asked, Why not for the same reason cancel the spiritual substance? The spiritual substance is not an idea or object of knowledge. We have no more right to assume it than the material substance. The only things we know to exist are our ideas. The development of the English school may be briefly put as follows:―― Locke, Spiritual substance――ideas――material substance. Berkeley, Spiritual substance――ideas. Hume, ideas. Hume is Locke made logically consistent. Berkeley went only halfway. Hume among these three was the only self-consistent empiricist. On the assumption that all knowledge is derived from sense-perception the history of the English empirical school was a history of the restriction of knowledge. =Berkeley’s Points of Agreement with Locke.= Berkeley starts from Locke’s psychological analysis as the basis of his own theory. The purely scientific aspect of the contents of mind as classified by Locke does not call for particular criticism from him. Logical classification does not seem to concern him very much, and while he accepts Locke’s analysis, he often calls Locke’s classes by other names. He commits himself to Locke’s psychological empiricism in the first sentence in his _Principles_: “It is evident to any one who takes a survey of the objects of knowledge, that they are either ideas actually imprinted on the senses; or else such as are perceived by attending to the passions and operations of the mind; or, lastly, ideas formed by the help of memory and imagination――either compounding, dividing, or barely representing those originally perceived in the aforesaid ways.” Our knowledge, therefore, deals only with ideas. There are the simple ideas of sensation and reflection, and ideas compounded from these.