As already remarked, Locke had not been wholly consistent with the standpoint of empiricism. Though conceding to material objects a decided superiority above the thinking subject, there was yet one point, viz., the recognition of substance, where he claimed for the thinking a power above the objective world. Among all the complex ideas which are formed by the subjective thinking, the idea of substance is, according to Locke, the only one which has objective reality; all the rest being purely subjective, with nothing actually corresponding to them in the objective world. But in the very fact that the subjective thinking places the conception of substance, which it has formed, in the objective world, it affirms an objective relation of things, an objective connection of them among each other, and an existing rationality. The reason of the subject in this respect stands in a certain degree above the objective world, for the relation of substance is not derived immediately from the world of sense, and is no product of sensation nor of perception through the sense. On a pure empirical standpoint—and such was Locke’s—it was therefore illogical to allow the conception of substance to remain possessed of objective being. If the understanding is essentially a bare and empty space, a white unwritten paper, if its whole content of objective knowledge consists in the impressions made upon it by material things, then must the conception of substance also be explained as a mere subjective notion, a union of ideas joined together at the mind’s pleasure, and the subject itself, thus fully deprived of every thing to which it could lay claim, must become wholly subordinated to the material world. This stride to a logical empiricism Hume has made in his criticism on the conception of causality. David Hume was born at Edinburgh 1711. Devoted in youth to the study of law, then for some time a merchant, he afterwards gave his attention exclusively to philosophy and history. His first literary attempt was hardly noticed. A more favorable reception was, however, given to his “_Essays_,”—of which he published different collections from 1742 to 1757, making in all five volumes. In these Hume has treated philosophical themes as a thoughtful and cultivated man of the world, but without any strict systematic connection. In 1752 he was elected to the care of a public library in Edinburgh, and began in this same year his famous history of England. Afterwards he became secretary of legation at Paris, where he became acquainted with Rousseau. In 1767 he became under secretary of state, an office, however, which he filled for only a brief period. His last years were spent in Edinburgh, in a quiet and contented seclusion. He died 1776.