The philosophical logic of Gottlob Frege. A commentary. With the texts of the prefaces to Grundgesetze der Arithmetik and Logische Untersuchungen I–IV. (Die philosophische Logik Gottlob Freges. Ein Kommentar. Mit den Texten des Vorworts zu Grundgesetze der Arithmetik und der Logischen Untersuchungen I–IV.) (German) Zbl 1220.03006

Künne, Wolfgang

Klostermann RoteReihe 30. Frankfurt am Main: Vittorio Klostermann (ISBN 978-3-465-04062-0/pbk). 840 p. (2010).

The book under review is dedicated to G. Frege’s contributions to philosophical logic, in particular his considerations on the relation between logic and language. Frege’s philosophy of language never lost its significance. It inspired and still inspires the most important directions in philosophy such as analytical philosophy.
This magnificent book gives a full-scale commentary on Frege’s work on philosophical logic. The author starts with a comprehensive, but well readable biography of Frege, placing Frege’s work on philosophical logic into the context of his life and work. The texts commented on are provided in critical editions. The following texts are presented: The preface to the first volume of the “Grundgesetze der Arithmetik” and the four papers of the series “Logische Untersuchungen”, i.e., “Der Gedanke” (1918), “Die Verneinung” (1919), “Gedankengefüge” (1923) and the fragment “Logische Allgemeinheit” (not before 1923, published posthumously).
The extensive commentaries of partially book-length size take up the central topics dealt with in the papers. The commentary on the introduction to the “Grundgesetze der Arithmetik” (212 pp.) explains the idea of a “Begriffsschrift” and fundamental concepts, among them “Bedeutung” and “Sinn”. It deals with singular terms, predicates, identity, truth values, and the prefix of a Begriffsschrift proposition. In a brilliant and sophisticated discussion of Frege’s “logical antipsychologism” the author compares Frege’s approach to logic with that of the great German philosophical logicians of the time, e.g., C. Sigwart and B. Erdmann, both labeled as “moderate psychologists”. The problems of translating Fregean terminology into the English language are critically discussed as well.
The chapter with commentaries on “Der Gedanke” (166 pp.) focuses on Frege’s concept of truth, possible truth bearers and his defense of thought as the object which can be said to be true. The author hints at the objectivity of thoughts, i.e., Frege’s denial of their psychical character. Special stress is laid on a comparison with Wittgenstein’s picture theory of meaning and truth.
The commentaries concerning “Die Verneinung” (46 pp.) deal with affirmative and negative answers to questions demanding a decision.
The next commentaries on “Das Gedankengefüge” (96 pp.) concern the creativity or productivity of language, in particular Frege’s suggestions concerning the construction of complexes of thought with the help of “AND”, “NOT” and other connectives. The final commentaries on “Logische Allgemeinheit” (74 pp.) present Frege’s theory of quantification.
An appendix is devoted to Frege’s position towards metalogical question, showing his closeness to Bolzano (pp. 759–769). The author collects and discusses Frege’s opinions on completeness, consistency and the freedom of abundancy of axiomatic systems. The book closes with an extensive bibliography and indices of persons and subjects.
This book is a breathtaking masterpiece, presenting Frege as an ingenious forerunner of analytical philosophy, at least in respect to modern philosophical logic and philosophy of language. The author’s deep and coherent interpretation of Frege’s philosophy is supported by a comprehensive and critical overview of previous research on the topic. He masters the challenge of holding the balance between historical exactness and systematic relevance in a excellent way.

Reviewer: Volker Peckhaus (Paderborn)

MSC:

03A05	Philosophical and critical aspects of logic and foundations
00A30	Philosophy of mathematics
01A55	History of mathematics in the 19th century
01A60	History of mathematics in the 20th century
03-01	Introductory exposition (textbooks, tutorial papers, etc.) pertaining to mathematical logic and foundations
03-03	History of mathematical logic and foundations

Keywords:

philosophy of logic; philosophy of language; psychologism; objectivity