The philosophy of Mansel, like that of his older contemporary Sir W. Hamilton of Edinburgh, was mainly due to three sources,— the works of Aristotle, the speculations of Kant, and the philosophy of Reid. Like Hamilton, Mansel maintained the purely formal character of logical science, the duality of consciousness as testifying to both self and the external world, and the limitation of knowledge to the finite and “conditioned.” His logical doctrines were developed in his edition of Aldrich’s Artis Logicae Rudimenta (1849)—his chief contribution to the reviving study of Aristotle— and in his Prolegomena Logica, —an Inquiry into the Psychological Character of Logical Processes (1851), in which the limits of logic as the “science of formal thinking” are rigorously determined. Tn his Bampton Lectures on The Limits of Religious Thought (1858) he applied to Christian theology the metaphysical agnosticism which seemed to result from Kant’s criticism, and which had been developed in Hamilton’s Philosophy of the Unconditioned. Showing the contradictions which arise when we attempt to conceive God under the categories of substance or cause, Mansel contends that we can have no positive conception either of the metaphysical or moral attributes of the Absolute and Infinite Being, though we are compelled to believe in His existence, the religious consciousness being built up by reflexion from the feeling of dependence and the conviction of moral obligation. Hence he infers the invalidity of all objections to revelation from its alleged inconsistency with the Divine character, maintaining the dependence of its claim to acceptance upon the evidences accompanying it. While denying all knowledge of the supersensuous, Mansel deviated from Kant in contending that cognition of the ego as it really is is itself a fact of experience. Consciousness, he held,—agreeing thus with the doctrine of “natural realism” which Hamilton developed from Reid,—implies knowledge both of self and of the external world. The latter ManseΓs psychology reduces to consciousness of our organism as extended; with the former is given consciousness of free-will and moral obligation. These views and a summary of his whole philosophy are contained in his article “Metaphysics” contributed to the 8th edition of the Encyclopaedia Britannica (separately published, I860). Mansel was also the author of an essay on The Philosophi/ of the Conditioned (1866) in reply to Mill’s criticism of Hamilton, of other controversial and occasional writings republished in Letters, Lectures, and Revieιvs (1873), and of lectures on The Gnostic Heresies (edited by J. B. Lightfoot, 1875).