of substance) of Locke. Bishop Berkeley, on the other hand, had evolved a system of pure Idealism from it, refuting Materialism by denying the very existence of matter. Hume, however, in his "Treatise on Human Nature" in 1738, and in his later works, pointed out that the principles established by Locke compel us to reject the notion of spirit equally with the notion of matter. Locke had inconsistently and arbitrarily admitted an objective value to the idea of substance; it was a complex idea, formed from the sense-impressions, and therefore devoid of objective validity. We are logically reduced to a knowledge of the sense-impressions of which we are conscious, and cannot get beyond them. We know nothing of substance, either material or spiritual, and nothing of causality; all our know ledge is merely an acquaintance with phenomena and their inter-relations. The result is, of course, pure scepticism: we can know nothing either of God or of the origin and destiny of man and the world. Such is the empirical system which has been adopted, with individual variations, by the English philosophical Rationalists of the present century.
Hume's philosophy was adopted and enforced, at the commencement of the century, by James Mill and his friend, Jeremy Bentham. Bentham will be more particularly noticed in connection with ethical utilitarianism, and James Mill soon gave place to the more powerful and more commanding influence of his son, John Stuart Mill, one of the most imposing figures in the philosophical and ethical circles of the century. Like Hume, he holds that all our know ledge is simply a knowledge of phenomena or appearances, and even this knowledge is relative, and not absolute; we are precluded, by the very nature of our minds, from attaining to a knowledge of anything beyond. Our sensations and their associations are the unique source of all knowledge; innate ideas and non-sensuous intuitions must be rejected. Even those axiomatic and invincible convictions to which the a priori and intuitionalist school appealed against him are only the result of accumulated impressions; the ideas of two-and-two and of four are so constantly associated in our experience that the bond is practically inseverable. The vindication of this aspect of the empirical philosophy is Mill's enduring merit; so, also, is his codification of the laws of association of states of consciousness.
