which alternatives involve us in impossibilities of thought.”—_Prin. of Psy.,_ § 399. Objections of another, though allied, class have been made in a review of the _Principles of Psychology_ by Mr. H. Sidgwick—a critic whose remarks on questions of mental philosophy always deserve respectful consideration. Mr. Sidgwick’s chief aim is to show what he calls “the mazy inconsistency of his [my] metaphysical results.” More specifically, he expresses thus the proposition he seeks to justify—“His view of the subject appears to have a fundamental incoherence, which shows itself in various ways on the surface of his exposition, but of which the root lies {239} much deeper, in his inability to harmonise different lines of thought.” Before dealing with the reasons given for this judgment, let me say that, in addition to the value which candid criticisms have as showing where more explanation is needed, they are almost indispensable as revealing to a writer incongruities he had not perceived. Especially where, as in this case, the subject-matter has many aspects, and where the words supplied by our language are so inadequate in number that, to avoid cumbrous circumlocution, they have to be used in senses that vary according to the context, it is extremely difficult to avoid imperfections of statement. But while I acknowledge sundry such imperfections and the resulting incongruities, I cannot see that these are, as Mr. Sidgwick says, fundamental. Contrariwise, their superficiality seems to me proved by the fact that they may be rectified without otherwise altering the expositions in which they occur. Here is an instance.