The Principles of Logic

THE following work makes no claim to supply any sys tematic treatment of Logic. I could not pretend to have acquired the necessary knowledge ; and in addition I confess that I am not sure where Logic begins or ends. I have adopted the title Principles of Logic, because I thought that my enquiries were mainly logical, and, for logic at least, must be fundamental. I feel that probability is against me. Experience has shown that most books on Logic add little to their subject. There is however one reflection which may weigh in my favour. Both in England and in Germany that subject is in motion. Logic is not where it was, and can not remain where it is. And when one works with the stream a slight effort may bring progress. I have in general not referred to those works to which I have been indebted. Amongst recent writers I owe most to Lotze, and after him to Sigwart. Wundt's book would have been more useful had it come to me earlier; and I may say the same of Bergmann's. I am under obligations to both Steinthal and Lazarus. And amongst English writers I have learned most from the late Professor Jevons. I may mention here that I should have owed certain observations to Mr. Balfour's able work, had I not seen it first when my book was completed. I should be glad to state my debts in detail, and in this way to express the gratitude I feel, but I doubt if it is now possible. I could not everywhere point out the original owners of my borrowed material, and I could not clearly state how much is not borrowed. I lay no claim to originality, except that, using the result of others' labour, I in some respects have made a sensible advance. I wished at first to avoid polemics altogether. But, though I have not sought out occasions of difference, it is plain that ix X PREFACE TO FIRST EDITION