Page:Popular Science Monthly Volume 15.djvu/773

Rh Brown-Séquard, on the causes of cadaveric rigidity, and also used it in my own book. For the deductive method, and the allied subjects of explanation and empirical and derivative law, the examples that we found were abundant. When, however, I suggested his adopting some from psychology, he steadily, and I believe wisely, resisted; and, if he took any of these, it was in the deductive department.

I was so much struck with the view of induction that regarded it as reasoning from particulars to particulars, that I suggested a further exemplification of it in detail, and he inserted two pages of instances that I gave him. On the last three books I had little to offer. I remember his saying, at a later period, that the fourth book (which I have always regarded as the crue materials of a logic of definition and classification) was made up of a number of subjects that he did not know where to place.

The "Logic" has been about the best attacked book of the time; and the author has in successive editions replied to objections and made extensive amendments. I have had myself full opportunities for expressing both agreements and dissents in regard to all the main points. Yet I could not pretend to say that criticism has been exhausted, or that imperfections and even inconsistencies may not even yet be pointed out. It is long since I was struck with the seeming incompatibility between the definition of logic in the introduction—viz., the science of proof, or evidence—and the double designation in the title—Principles of Evidence and the Methods of Scientific Investigation. Previous writers laid little stress on proof, and Mill took the other extreme and made proof everything. Bacon, Herschel, and Whewell seemed to think that, if we could only make discoveries, the proof would be readily forthcoming—a very natural supposition with men educated mainly in mathematics and physics. Mill, from his familiarity with the moral and political sciences, saw that proof was more important than discovery. But the title, although larger than the definition, is not larger than the work; he did discuss the methods of investigation, as aids to discovery, as well as means of proof; only, he never explained the mutual bearings of the two. Any one that tries will find this not an easy matter.

The sixth book was the outcome of his long study of politics, both practical and theoretical, to which the finishing stroke was given by the help of Auguste Comte. I will return to this presently.

In five months he carried the work through the press, and brought it out in March, 1843. We may form some estimate of the united labor of correcting proof-sheets, often one a day, of reconsidering the new examples that have been suggested, of reading Liebig's two books, and Comte's sixth volume (nearly a thousand pages), and of recasting the concluding chapters. From the moment of publication, the omens were auspicious. Parker's trade-sale was beyond his anticipations, and the book was asked for by unexpected persons, and appeared in