A
SYSTEM OF LOGIC
RATIOCINATIVE AND INDUCTIVE
VOL. I.
LONDON:
LONGMANS, GREEN, READER, AND DYER
MDCCCLXVIII
This book makes no pretence of giving to the world a new theory of theintellectual operations. Its claim to attention, if it possess any, isgrounded on the fact that it is an attempt not to supersede, but toembody and systematize, the best ideas which have been eitherpromulgated on its subject by speculative writers, or conformed to byaccurate thinkers in their scientific inquiries.
To cement together the detached fragments of a subject, never yettreated as a whole; to harmonize the true portions of discordanttheories, by supplying the links of thought necessary to connect them,and by disentangling them from the errors with which they are alwaysmore or less interwoven; must necessarily require a considerable amountof original speculation. To other originality than this, the presentwork lays no claim. In the existing state of the cultivation of thesciences, there would be a very strong presumption against any one whoshould imagine that he had effected a revolution in the theory of theinvestigation of truth, or added any fundamentally new process to thepractice of it. The improvement which remains to be effected in themethods of philosophizing (and the author believes that they have muchneed of improvement) can only consist in performing, more systematically[Pg vi]and accurately, operations with which, at least in their elementaryform, the human intellect in some one or other of its employments isalready familiar.
In the portion of the work which treats of Ratiocination, the author hasnot deemed it necessary to enter into technical details which may beobtained in so perfect a shape from the existing treatises on what istermed the Logic of the Schools. In the contempt entertained by manymodern philosophers for the syllogistic art, it will be seen that he byno means participates; though the scientific theory on which its defenceis usually rested appears to him erroneous: and the view which he hassuggested of the nature and functions of the Syllogism may, perhaps,afford the means of conciliating the principles of the art with as muchas is well grounded in the doctrines and objections of its assailants.
The same abstinence from details could not be observed in the FirstBook, on Names and Propositions; because many useful principles anddistinctions which were contained in the old Logic, have been graduallyomitted from the writings of its later teachers; and it appeareddesirable both to revive these, and to reform and rationalize thephilosophical foundation on which they stood. The earlier chapters ofthis preliminary Book will consequently appear, to some readers,needlessly elementary and scholastic. But those who know in whatdarkness the nature of our knowledge, and of the processes by which itis obtained, is often involved by a confused apprehension of the importof the different classes of Words and Assertions, will not regard thesediscussions as either frivolous, or irrelevant to the topics consideredin the l