When two persons have their thoughts and speculations completely in common; when all subjects of intellectual or moral interest are discussed between them in daily life, and probed to much greater depths than are usually or conveniently sounded in writings intended for general readers; when they set out from the same principles, and arrive at their conclusions by processes pursued jointly, it is of little consequence in respect to the question of originality, which of them holds the pen; the one who contributes least to the composition may contribute more to the thought; the writings which result are the joint product of both, and it must often be impossible to disentangle their respective parts, and affirm that this belongs to one and that to the other. In this wide sense, not only during the years of our married life, but during many of the years of confidential friendship which preceded, all my published writings were as much her work as mine; her share in them constantly increasing as years advanced. But in certain cases, what belongs to her can be distinguished, and specially identified. Over and above the general influence which her mind had over mine, the most valuable ideas and features in these joint productions--those which have been most fruitful of important results, and have contributed most to the success and reputation of the works themselves--originated with her, were emanations from her mind, my part in them being no greater than in any of the thoughts which I found in previous writers, and made my own only by incorporating them with my own system of thought! During the greater part of my literary life I have performed the office in relation to her, which from a rather early period I had considered as the most useful part that I was qualified to take in the domain of thought, that of an interpreter of original thinkers, and mediator between them and the public; for I had always a humble opinion of my own powers as an original thinker, except in abstract science (logic, metaphysics, and the theoretic principles of political economy and politics), but thought myself much superior to most of my contemporaries in willingness and ability to learn from everybody; as I found hardly anyone who made such a point of examining what was said in defence of all opinions, however new or however old, in the conviction that even if they were errors there might be a substratum of truth underneath them, and that in any case the discovery of what it was that made them plausible, would be a benefit to truth. I had, in consequence, marked this out as a sphere of usefulness in which I was under a special obligation to make myself active; the more so, as the acquaintance I had formed with the ideas of the Coleridgians, of the German thinkers, and of Carlyle, all of them fiercely opposed to the mode of thought in which I had been brought up, had convinced me that along with much error they possessed much truth, which was veiled from