Ignacio Angelelli

I wish to express, first of all, my profound gratitude to Professor J. M. Bochenski, without whose assistance the present work would have not been possible. To be concise, I would like to state that his contribution to this book may be viewed at three levels: (1) that of the general spirit, (2) that of the specific ideas, theses or approaches which are expressed in its pages, (3) that of this work qua doctoral dissertation. The general spirit which has guided my research coincides with that underlying Professor :Oochenski's own works, in particular his Formale Logik (Munchen 1956). Moreover, the particular occasion which suggested my investigation was a statement included in that book according to which the literature in the field still lacked a detailed work on Frege (p. 317). I wish, likewise, to express my gratitude to other professors of the University of Fribourg for their generous help. I mention especially Professors P. Wyser, M. D. Philippe, N. Luyten, and V. Kuiper. I have also benefited from Professor E. Specker's lectures at the Eidge nossische Technische Hochschule (ZUrich) and from Professor Olof Gigon's lectures at the University of Bern. From an earlier period I wish to express my gratitude to the professors of the philosophy department of the Universidad Nacional de Buenos Aires, especially the late Professor Francisco Romero. The Swiss National Library (Bern) has greatly facilitated access to bibliographical sources, and the library of the University of Munster (Westphalien) has kindly provided microfilms of Frege's Nachlap.

The author distinguishes a "term logic," where terms are the fundamental units, and a "sentential logic," where sentences are the fundamental units. Although this technical distinction is presented by Englebretsen as a war-like opposition throughout the entire history of logic, he reassures us that "no blood has been spilled". In recent times, the term-logic party has been eclipsed by the sentential-logic band; term logic is nowadays "almost mute". Only F. Sommers appears to proclaim the truth of term logic in the twentieth century. The author's main goal is to "recount the history" of term logic through an examination of its three champions: Aristotle, Leibniz, and Sommers. The chronological sequence of these three logicians is a sequence towards perfection as well. The shortcomings of Aristotle's achievement are partially corrected by Leibniz and then fully repaired by Sommers, who finally extends the Aristotelian syllogistic into a "universal logic". Englebretsen himself has added "certain emendations and extensions in a modest way".