In our own country and in our own time, without incessant reference, express or tacit, to his treatment of them. On all the subjects on which he touched, he is either one of the most powerful allies of what I deem a sound philosophy, or (more frequently) by far its most formi dahle antagonist; both because he came the latest, and wrote with a full knowledge of the ?aws which had been detected in his predecessors, and because he was one of the ablest, the most clear-sighted, and the most candid. W'henever any Opinion which he deliberately expressed is contended against, his form of the Opinion, and his arguments for it, are those which especially require to be faced and carefully appreciated; and it being thus impossible that any fit discussion of his topics should not involve an estimate of his doctrines, it seems worth while that the estimate should be rendered as complete as practicable, by being extended to all the subjects on which he has made, or on which he is believed to have made, any important contribution to thought.