In this book I have tried to treat deduction from the objective standpoint that everybody assumes in the treatment of induction. Consequently I have omitted the traditional rules of the syllogism and put in their place a direct statement of the principles on which we reason in the different figures, adding certain 'cautions' that must be observed if the principles are not to be misapplied; and I have treated conversion and obversion in much the same way.
The fourth figure of the syllogism seemed to me not to represent any distinct principle of reasoning, and therefore to have no proper place in the objective treatment of logic; but I have explained the traditional way of dealing with it. The algebra' of logic I have omitted altogether. Readers interested in it are referred to the "Johns Hopkins Studies in Logic" (Little, Brown & Co., Boston).
However imperfect my own treatment of deduction from the objective standpoint may be, I believe that the standpoint itself is not only more correct philosophically than the subjective, but also better pedagogically; for we do far more to make a student clear-headed by teaching him to look a situation in the face and analyze it than by giving him any amount of dexterity in the reduction of arguments to a given verbal form.
My indebtedness to other authors is apparent. I am no less indebted to individuals-particularly to colleagues in other departments who have given me valuable suggestions on matters related to their special subjects; but most of all to Dr. W. T. Marvin, to whom I read the whole book while it was still in manuscript.