Of the special books bearing the title of the History of Logic, there is really only one--that of Charles Prantl--which, based upon wide researches, is truly remarkable for its doctrine and for lucid and animated exposition. Unfortunately this does not go further than the fifteenth century and omits the whole movement of modern philosophy.[1] But even the period exhaustively treated by him (Antiquity and the Middle Ages) is looked at from the narrow angle of an Aristotelian and formal temperament. Other works bearing the same title are not worthy of attention.[2] On the other hand, the better histories of Logic must not be sought under this title, but especially in the better Histories of Philosophy, beginning with that of Hegel, which, for the most part, is precisely a history of Logic. In inaugurating a new treatment, governed by the principles which we have defended, we shall confine ourselves, in the following pages, to a sketch of the history of some of the principal parts of logical doctrine, without any claim to even approximate completeness, and with a view to giving simple illustrations of the things that were said in the theoretical part. In this theoretical part, in virtue of the identity of philosophy and history which we have explained, history may be said to be already contained and projected, even though names and dates are mostly omitted and left to be understood. [Footnote 1: _Geschichte der Logik im Abendlande,_ Leipzig, 1855-1870, 4 vols. Scattered memoirs of certain writers belonging to later times are being published by Prantl in academic journals, and it would be opportune to collect these in a volume.] [Footnote 2: A rapid sketch, compiled in part from the work of Prantl, with a polemical addition directed against the adversaries of the Hegelian Logic, precedes the _Logic_² of Kuno Fischer. The historical part of the _System der Logik_ of Ueberweg (fifth edition, 1882, edited by J. B. Meyer) has an almost exclusively bibliographical character with excerpts, and that contained in L. Rabus, _Logik ii. System der Wissenschaften,_ Erlangen-Leipzig, 1895, is yet more arid. The _Gesch. d. Logik_ of F. Harms (Berlin, 1881) is meagre in facts, verbose and vague. In recent monographs on special points, one feels the effect of what is called Logistic or new formalism, which makes the authors pursue ineptitudes and curiosities of slight value.] II THE THEORY OF THE CONCEPT [Sidenote: _Question as to who was the "father of Logic."_]