All this is very thorough in its way; but, in the first place, it applies chiefly to argumentative works, and, in the second place, it is entirely beyond the powers of ordinary students. Such an examination of an author as Locke contemplates is not seen many times in a generation. His own controversies give but indifferent examples of it; several of Bentham's works and a few of John Mill's polemical articles also give an idea of thorough handling; but it is not so properly a studious effort, as the consummated product of a highly logical discipline, and is within the reach of only a small elect number. Locke would have been more intelligible, if, instead of telling us to strip an author's meaning of the words, he had impressed strongly the necessity of _defining all leading terms_; and of making sure that each was always used in the same meaning. While, in order to veracious conclusions, it is necessary that every matter of fact should be truly given, it is equally necessary that the language should be free from ambiguity. If an author uses the word "law," at one time as an enactment: by some authority, and at another time, as a sequence in the order of nature, he is sure to land us in fallacy and confusion, as Butler did in explaining the Divine government. The remedy is, not to perform the operation of separating the meaning entirely from the language, but to vary the language, so as to substitute terms that have no ambiguity. "Law" is equivocal; "social enactment," and "order of nature," are both unequivocal; and when one is chosen, and adhered to, the confusion is at an end. The mere art of study is no preparation for such a task. It demands a very advanced condition of knowledge on the particular subject, as well as a logical habit of mind, however acquired; and to include it in a practical essay on the Conduct of the Understanding is to overstep the limits of the subject. * * * * *