"In regard to what I have said of Mill... I should not have expressed so strong an opinion had I been thinking only of his political economy. There is much that is erroneous in his Principles, and he never had an idea what capital was, but the book is not the maze of self-contradictions which his logic undoubtedly is. If you have not examined his logical theories very critically, you will hardly be aware that upon the principal points he usually holds from three to six inconsistent views all at the same time."