LOGIC FROM ARISTOTLE TO BACON, the long history of philosophic thought from Aristotle to the beginning of the modern period furnishes no new conception of logic so complete and methodical as to require detailed treatment, but exhibits alterations in special doctrines, additions, and new points of view numerous enough to account for a certain radical change in the mode of regarding logic which is, for our present purpose, the only interesting feature. This change may perhaps be expressed not inaccurately as the tendency towards formalizing logic. Gradually logical researches came to have their boundaries extended in one way by the introduction of new matter, and narrowed in another by restriction of logical consideration to one special aspect of knowledge. Much in the history of this movement still remains in obscurity, but the general result is sufficiently clear. The periods into which the historical development of logic throughout this long interval may be naturally divided, with their main characteristics, are the following.: (1) The Peripatetic School, represented by Thcophrastus and Endemus, following in the main the Aristotelian tradition, but deviating in certain fundamental respects, and on time whole treating the matter of logical research as though it were separate from and independent of the theory of knowledge as a whole. To this school is due the distinct recognition of the hypothetical and disjunctive proposition and syllogism, and the more complete enumeration of the possible valid modes of categorical reasoning. In both cases the additions are made to turn upon purely formal considerations. The hypothetical and disjunctive judgments are treated as given varieties, to be discerned in ordinary language and expression, not as resting upon any fundamentally distinct principle or activity of thoughts The addition of five indirect moods to those recognized by Aristotle as belonging to the first figure proceeds on the purely formal ground of difference in position of the middle term iu the two premisses. (2) The Epicurean and Stoic Logics. Of these the Epicurean presents no points of interest. The Stoic logic, on the other hand, is the first example of a purely formal doctrine based on and associated with a thoroughly empirical theory of cognition. In essence the Stoic doctrine is identical with that of Antistheues, above noted, and it is interesting to observe that, under the purely nominalist theory, logic becomes almost identical with the doctrine of expression, or rhetoric. The theory of naming, and that of the conjunction of names in propositions, are the fundamental portions of the body of logic. Naturally the Stoic logicians tended to increase the bulk of logic by introducing numerous distinctions of language, and by signalizing varieties of judgment dependent on varieties of verbal expression. (3) The acceptation of Logic among the Romans. Here there must be distinguished the quasi-rhetorical logic, such as is found in Cicero, which is altogether Stoic in character, and the Aristotelian logic, as developed by Boetius with the additions of the later commentators. In Boetius one 11 otes specially the technical or formal character of the treatment, which was of special importance historically, from the fact that the earlier scholastic writers derived their main knowledge of logic from certain of the treatises of Boetius. (4) The Scholastic Logic. On the details of the scholastic logic it is not necessary to enter, but there must be noted the following points as of interest in determining what may well be called the current conception of the Aristotelian logic in modern times. The earlier scholastics, in possession of but few of Aristotle's writings, added nothing of importance to the body of logical researches, and the permanent subject of discussion, the nature of universals, did not, through any of its solutions, affect the treatment of logical doctrines. The introduction of the body of the Aristotelian writings was contemporaneous with the introduction of the Arab writings and commentaries into western Europe, and there grew up therewith a more developed treatment of what may be called the psychological element of logic. The logic of the later scholastics is characterized by two points of interest, historically unconnected, hut having a natural affinity, - the one, the introduction of an immense mass of subtle distinctions, mainly verbal, making up the body of the Parra Logicalia, the other, the influence of the nominalist conception of thoughts The peculiarity of the nominalist view is the severance of immediate apprehension from discursive thought, the assignment of all matter of knowledge to the one, and of all form to the other. But form, under this conception of discursive thought, can be found only in the generalizing function of signs or names ; accordingly the fundamental processes of logical thought are regarded as so many modes of application of names. The later nominalist logicians were thus naturally led to the expenditure of immense subtlety and diligence on the thorny problems of the Pa-rca Logiealia, while at the same time the peculiar inner difficulty of the theory became apparent as its consequences were worked out. (5) The Reaction against Aristotelianism and the Humanist Modification of Logic. Little of positive value for logical theory is offered by the numerous works representing this stage of historical development. Valle, Agricola, and Vives, with much good criticism in general spirit and detail, present a rhetorico-grammatical logic that resembles most closely Cicero's eclectic reproduction of Stoicism. Remus, the only logician of the period with historic renown, contributes really nothing to the history of logic, his innovations consisting mainly in the omission of the most valuable portions of the genuine Aristotelic logic, the insertion of practical and interesting examples, and finally rearrangement or redistribution of the heads under which logical doctrine was expounded. The liamist school, most numerous and flourishing, produced no logical work of the first importance."' The net result of this whole period was the severance of a certain body of doctrine, formal in character (the theory of second intentions), from theory of knowledge generally, and from all the concrete sciences. The boundaries and even the functions of this doctrine remained unfixed, for difference regarding fundamental points of extra-logical theory led to difference in mode of treatment, as well as to difference in conceptions of the end and value of logic.