Information about Gottlob Frege

Western Philosophy 19th-century philosophy,
Friedrich Ludwig Gottlob Frege
Name:	Friedrich Ludwig Gottlob Frege
Birth:	November 8, 1848
Death:	26 July, 1925
School/tradition:	Analytic philosophy
Main interests:	Philosophy of mathematics, mathematical logic, Philosophy of language
Notable ideas:	Predicate calculus, Logicism, Sense and reference
Influenced:	Giuseppe Peano, Bertrand Russell, Rudolf Carnap, Ludwig Wittgenstein, Michael Dummett, Edmund Husserl, and most of the analytic tradition

Friedrich Ludwig Gottlob Frege (8 November 1848, Wismar, Grand Duchy of Mecklenburg-Schwerin – 26 July 1925, , Germany) (IPA: [ˈgɔtlop ˈfʁeːgə]) was a German mathematician who became a logician and philosopher. He helped found both modern mathematical logic and analytic philosophy. His work has exerted a fundamental and far-reaching influence on 20th-century philosophy, especially in English-speaking countries.

Life

Childhood (1848–1869)

Frege was born in 1848 in Wismar, in the state of Mecklenburg-Schwerin (the modern German federal state Mecklenburg-Vorpommern). His father, Karl Alexander Frege, was the founder of a girls' high school, of which he was the headmaster until his death in 1866. From this time, the school was led by Frege's mother, Auguste Wilhelmine Sophie Frege (née Bialloblotzky). His mother in all likelihood had Polish roots.

Already in his childhood, Frege encountered philosophies which would guide his future scientific career. For example, his father wrote a textbook on the German language for children aged 9-13, the first section of which dealt with the structure and logic of language.

Frege studied at a Gymnasium in Wismar, and graduated at the age of 15. His teacher Leo Sachse (also a poet) played the most important role in determining his future scientific career, encouraging him to continue his studies at the University of Jena.

Studies at University: Jena and Göttingen (1869–1874)

Frege signed up to the University of Jena in the spring of 1869 as a citizen of the North German Federation. In the four semesters of his studies there he attended around 20 lectures, primarily on mathematics and physics. The progress he made in his studies was excellent.

His most important teacher was Ernst Abbe (physicist, mathematician and inventor). Abbe gave Frege lectures on The Theory of Gravity, Galvanism and electrodynamics, The theory of functions of a complex variable, Applications of physics, Selected divisions of mechanics, and The mechanics of solids. Abbe, not as a teacher, but as director of Zeiss, the optical manufacturers, and as a trusted friend had a great effect on Frege, and after Frege's (absolution?) they came into closer correspondence.

His other notable university teachers were Karl Snell (subjects: The use of infinitesimal analysis in geometry, The analytical geometry of planes, Analytical mechanics, Optics, The physical foundations of mechanics); Hermann Schäffer (Analytical geometry, Applied physics, Algebraic analysis, On the telegraph and other electronic machines); and a famous philosopher, Kuno Fischer (The history of Kantian and critical philosophy).

In 1871, Frege continued his studies in Göttingen, the leading university in mathematics in German-speaking territories. Here, he attended the lectures of Alfred Clebsch (Analytical geometry), Ernst Schering (Function theory), Wilhelm Weber (Physical studies, Applied physics), Eduard Riecke (The theory of electricity) and (in the words of Werner Stelzner), "ingenious philosopher" Rudolf Hermann Lotze (The philosophy of religion). In many aspects, the ideologies of Frege and Lotze agree: in the philosophy of Frege, there are many items which point to Lotze's influence (for example, they both expressed strong opposition to one of the era's new philosophical sciences, psychology), and it has been the object of many debates whether he gained these ideas in his time at Göttingen and primarily due to Lotze: this is not for sure.

In 1873 Frege attained his doctorate with Ernst Schering, with a dissertation under the title of "Über eine geometrische Darstellung der imaginären Gebilde in der Ebene" ("'On a Geometrical Representation of Imaginary Forms in a Plane"), in which he aimed to solve such fundamental problems in geometry as the mathematical interpretation of projective geometry's infinitely distant (imaginary) points.

Work as a Logician

Main article: Begriffsschrift

Though his education and early work were mathematical, and especially geometrical, Frege's thought soon turned to logic. His 1879 Begriffsschrift (Concept Script) marked a turning point in the history of logic. The Begriffsschrift broke much new ground, including a clean treatment of functions and variables. Frege wanted to show that mathematics grew out of logic, but in so doing devised techniques that took him far beyond the Aristotelian syllogistic and Stoic propositional logic that had come down to him in the logical tradition. In effect, he invented axiomatic predicate logic, in large part thanks to his invention of quantified variables, which eventually became ubiquitous in mathematics and logic, and solved the problem of multiple generality. Though previous logic had dealt with the logical constants and, or, if...then..., not, and some and all, iterations of these operations were little understood; even the distinction between a pair of sentences like "every boy loves some girl" and "some girl is loved by every boy" could not be represented. It is sometimes noted that Aristotle's logic would not be able to represent even the most elementary inferences in Euclid's geometry, but Frege's "conceptual notation" could represent inferences involving indefinitely complex mathematical statements. Hence the analysis of logical concepts and the machinery of formalization that is essential to Bertrand Russell's theory of descriptions and Principia Mathematica (with Alfred North Whitehead), and to Gödel's incompleteness theorems, and to Alfred Tarski's theory of truth, is ultimately due to Frege.

Frege's purpose was to defend the view that arithmetic is a branch of logic, a view known as logicism. Already in the 1879 Begriffschrifft important preliminary theorems related to mathematical induction were derived within pure logic.

In his later Grundgesetze der Arithmetik (1893, 1903), published at its author's expense, he attempted to derive all of the laws of arithmetic from axioms he asserted as logical. Most of these axioms were carried over from his Begriffsschrift, though not without some significant changes. The one truly new principle was one he called the Basic Law V: the "value-range" of the function f(x) is the same as the "value-range" of the function g(x) if and only if ∀x[f(x) = g(x)]. In modern notation and terminology, let {x|Fx} denote the extension of the predicate Fx, and similarly for Gx. Then Basic Law V says that the predicates Fx and Gx have the same extension iff ∀x[Fx ↔ Gx].

In a famous episode, Bertrand Russell wrote to Frege, just as Vol. 2 of the Grundgesetze was about to go to press in 1903, showing that Russell's paradox could be derived from Frege's Basic Law V. (This letter and Frege's reply thereto are translated in Jean van Heijenoort 1967.) Hence the system of the Grundgesetze was inconsistent. Frege wrote a hasty last-minute appendix to vol. 2, deriving the contradiction and proposing to eliminate it by modifying Basic Law V.

Frege's proposed remedy was subsequently shown to imply that there is but one object in the universe of discourse, and hence is worthless (indeed this would make for a contradiction in Frege's system if he had axiomatized the idea, fundamental to his discussion, that the True and the False are distinct objects; see e.g. Dummett 1973). But recent work has shown that much of the program of the Grundgesetze might be salvaged in other ways:

• Basic Law V can be weakened in other ways. The best-known way is due to George Boolos. A "concept" F is "small" if the objects falling under F cannot be put in 1-to-1 correspondence with the universe of discourse, that is, if: ¬∃R[R is 1-to-1 & ∀x∃y(xRy & Fy)]. Now weaken V to V*: a "concept" F and a "concept" G have the same "extension" if and only if neither F nor G is small or ∀x(Fx ↔ Gx). V* is consistent if second-order arithmetic is, and suffices to prove the axioms of second-order arithmetic.
• Basic Law V can simply be replaced with Hume's Principle, which says that the number of Fs is the same as the number of Gs if and only if the Fs can be put into a one-to-one correspondence with the Gs. This principle too is consistent if second-order arithmetic is, and suffices to prove the axioms of second-order arithmetic. This result is termed Frege's Theorem because it was noticed that in developing arithmetic, Frege's use of Basic Law V is restricted to a proof of Hume's Principle; it is from this in turn that arithmetical principles are derived. On Hume's Principle and Frege's Theorem, see http://plato.stanford.edu/entries/frege-logic/.
• Frege's logic, now known as second-order logic, can be weakened to so-called predicative second-order logic. However, this logic, although provably consistent by finitistic or constructive methods, can interpret only very weak fragments of arithmetic.

Frege's work in logic was little recognized in his day, in considerable part because his peculiar diagrammatic notation had no antecedents; it has since had no imitators. Moreover, until Principia Mathematica appeared, 1910-13, the dominant approach to mathematical logic was still that of George Boole and his descendants, especially Ernst Schroeder. Frege's logical ideas nevertheless spread through the writings of his student Rudolph Carnap and other admirers, particularly Bertrand Russell and Ludwig Wittgenstein.

It has been argued, most energetically in Fredric W. Katz's doctoral dissertation, "Sets and Their Sizes," that Frege is the father of the relational database.

Philosopher

Main article: On Sense and Reference

Frege is one of the founders of analytic philosophy, mainly because of his contributions to the philosophy of language, including the:

• Function-argument analysis of the proposition;
• Distinction between concept and object (Begriff und Gegenstand);
• Principle of compositionality;
• Context principle;
• Distinction between the sense and reference (Sinn und Bedeutung) of names and other expressions, sometimes said to involve a mediated reference theory.

As a philosopher of mathematics, Frege attacked the psychologistic appeal to mental explanations of the content of judgment of the meaning of sentences. His original purpose was very far from answering general questions about meaning; instead, he devised his logic to explore the foundations of arithmetic, undertaking to answer questions such as "What is a number?" or "What objects do number-words ("one", "two", etc.) refer to?" But in pursuing these matters, he eventually found himself analysing and explaining what meaning is, and thus came to several conclusions that proved highly consequential for the subsequent course of analytic philosophy and the philosophy of language.

It should be kept in mind that Frege was employed as a mathematician, not a philosopher, and published his philosophical papers in scholarly journals that often were hard to access outside of the German speaking world. He never published a philosophical monograph other than The Foundations of Arithmetic, much of which was mathematical in content, and the first collections of his writings appeared only after World War II. A volume of English translations of Frege's philosophical essays first appeared in 1952, edited by students of Wittgenstein, Peter Geach and Max Black - with the bibliographic assistance of Wittgenstein (see Geach ed. 1975, introduction). Hence despite the generous praise of Russell and Wittgenstein, Frege was little known as a philosopher during his lifetime. His ideas spread chiefly through those he influenced, such as Russell, Wittgenstein, and Carnap, and through Polish work on logic and semantics.

"Sinn" and "Bedeutung"

The distinction between Sinn and Bedeutung (usually translated "Sense and Reference", but also as "Sense and Meaning" or "Sense and Denotation") was an innovation of Frege in his 1892 paper Über Sinn und Bedeutung ("On Sense and Reference"). According to Frege, sense and reference are two different aspects of the significance of an expression. Frege applied "Bedeutung" in the first instance to proper names, where it means the bearer of the name, the object in question, but then also to other expressions, including complete sentences, which bedeuten the two "truth values", the true and the false; by contrast, the sense or Sinn associated with a complete sentence is the thought it expresses. The sense of an expression is said to be the "mode of presentation" of the item referred to. The distinction can be illustrated thus: In their ordinary uses, the name "Charles Philip Arthur George Mountbatten-Windsor," which for logical purposes is an unanalyzable whole, and the functional expression "the Prince of Wales," which contains the significant parts "the prince of ξ" and "Wales", have the same reference, namely the person best known as Prince Charles. But the sense of the word "Wales" is a part of the sense of the latter expression, but no part of the sense of the "full name" of Prince Charles. These distinctions were disputed by Bertrand Russell, especially in his paper "On Denoting"; the controversy has continued into the present, fueled especially by the famous lectures on "Naming and Necessity" of Saul Kripke.

Important dates

• Born November 8, 1848 in Wismar, Mecklenburg-Schwerin.
• 1869 - attends the University of Jena.
• 1871 - attends the University of Göttingen.
• 1873 - PhD, doctor in mathematics (geometry), attained at Göttingen.
• 1874 - Habilitation at Jena; private teacher.
• 1879 - Professor Extraordinarius at Jena.
• 1896 - Ordenlicher Honorarprofessor at Jena.
• 1917 or 1918 - retires.
• Died July 26, 1925 in Bad Kleinen (now part of Mecklenburg-Vorpommern).

Important Works

First-order logic and foundations of arithmetic

Begriffsschrift (1879)

• Original: Begriffsschrift, eine der arithmetischen nachgebildete Formelsprache des reinen Denkens, Halle a. S., 1879;
• In English: Concept Notation, the Formal Language of the Pure Thought like that of Arithmetics).

The Foundations of Arithmetic (1884)

• Original: Die Grundlagen der Arithmetik: eine logisch-mathematische Untersuchung über den Begriff der Zahl; Breslau, 1884;
• In English: The Foundations of Arithmetic: the logical-mathematical investigation of the Concept of Number.

Basic Laws of Arithmetic, Vol. 1 (1893); Vol. 2 (1903)

• Original: Grundgesetze der Arithmetik, Jena: Verlag Hermann Pohle, Band I (1893), Band II (1903);
• In English: Basic Laws of Arithmetic.

Philosophical studies

Function and Concept (1891)

• Original: Funktion und Begriff : Vortrag, gehalten in der Sitzung; vom 9. Januar 1891 der Jenaischen Gesellschaft für Medizin und Naturwissenschaft, Jena, 1891;
• In English: Function and Concept.

On Sense and Reference (1892)

• Original: Über Sinn und Bedeutung; in Zeitschrift für Philosophie und philosophische Kritik C (1892): 25-50;
• In English: On Sense and Reference.

Concept and Object (1892)

• Original: Über Begriff und Gegenstand, in Vierteljahresschrift für wissenschaftliche Philosophie XVI (1892): 192-205;
• In English: Concept and Object.

What is a Function? (1904)

• Original (in German): Was ist eine Funktion?, in Festschrift Ludwig Boltzmann gewidmet zum sechzigsten Geburtstage, 20. Februar 1904, S. Meyer (ed.), Leipzig, 1904, pp. 656-666;
• In English: What is a Function?

Logical Investigations (1918–1923) Frege intended that the following three papers be published together in a book titled Logische Untersuchungen (Logical Investigations). Though the German book never appeared, English translations did appear together in Logical Investigations, ed. Peter Geach, Blackwells, 1975.

• 1918-19. "Der Gedanke: Eine logische Untersuchung (Thought: A Logical Investigation)" in Beiträge zur Philosophie des Deutschen Idealismus I: 58-77.
• 1918-19. "Die Verneinung" (Negation)" in Beiträge zur Philosophie des deutschen Idealismus I: 143-157.
• 1923. "Gedankengefüge (Compound Thought)" in Beiträge zur Philosophie des Deutschen Idealismus III: 36-51.

Articles on Geometry

• 1903: Über die Grundlagen der Geometrie. II. Jaresbericht der deutschen Mathematiker-Vereinigung XII (1903), 368-375;
• In English: On the Foundations of Geometry.
• 1967: Kleine Schriften. (I. Angelelli, ed.) Wissenschaftliche Buchgesellschaft. Darmstadt, 1967 és G. Olms, Hildescheim, 1967. "Small Writings", a collection of most of his writings (e.g. the previous), posthumously published.

References

Primary

• Online bibliography of Frege's works and their English translations.
• 1879. Begriffsschrift, eine der arithmetischen nachgebildete Formelsprache des reinen Denkens. Halle a. S.: Louis Nebert. Translation: Concept Script, a formal language of pure thought modelled upon that of arithmetic, by S. Bauer-Mengelberg in Jean Van Heijenoort, ed., 1967. From Frege to Gödel: A Source Book in Mathematical Logic, 1879-1931. Harvard University Press.
• 1884. Die Grundlagen der Arithmetik: eine logisch-mathematische Untersuchung über den Begriff der Zahl. Breslau: W. Koebner. Translation: J. L. Austin, 1974. The Foundations of Arithmetic: A logico-mathematical enquiry into the concept of number, 2nd ed. Blackwell.
• 1891. "Funktion und Begriff." Translation: "Function and Concept" in Geach and Black (1980).
• 1892a. "Über Sinn und Bedeutung" in Zeitschrift für Philosophie und philosophische Kritik 100: 25-50. Translation: "On Sense and Reference" in Geach and Black (1980).
• 1892b. "Über Begriff und Gegenstand" in Vierteljahresschrift für wissenschaftliche Philosophie 16: 192-205. Translation: "Concept and Object" in Geach and Black (1980).
• 1893. Grundgesetze der Arithmetik, Band I. Jena: Verlag Hermann Pohle. Band II, 1903. Partial translation: Furth, M, 1964. The Basic Laws of Arithmetic. Uni. of California Press.
• 1904. "Was ist eine Funktion?" in Meyer, S., ed., 1904. Festschrift Ludwig Boltzmann gewidmet zum sechzigsten Geburtstage, 20. Februar 1904. Leipzig: Barth: 656-666. Translation: "What is a Function?" in Geach and Black (1980).
• Peter Geach and Max Black, eds., and trans., 1980. Translations from the Philosophical Writings of Gottlob Frege, 3rd ed. Blackwell (1st ed. 1952).

Secondary

• Anderson, D. J., and Edward Zalta, 2004, "Frege, Boolos, and Logical Objects," Journal of Philosophical Logic 33: 1-26.
• Baker, Gordon, and P.M.S. Hacker, 1984. Frege: Logical Excavations. Oxford University Press.

^{Vigorous, if controversial, criticism of both Frege's philosophy and influential contemporary interpretations such as Dummett's.}

• Burgess, John, 2005. Fixing Frege. Princeton Univ. Press.

^{A critical survey of the work by Boolos, Heck, and others attempting to rehabilitate Frege's logicism.}

• Boolos, George, 1998. Logic, Logic, and Logic. MIT Press.

^{Contains 12 papers on Frege's logic and logistic approach to the foundations of arithmetic.}

• Diamond, Cora, 1991. The Realistic Spirit. MIT Press.

^{Ostensibly about Wittgenstein, but contains several valuable articles on Frege.}

• Dummett, Michael, 1973. Frege: Philosophy of Language. Harvard University Press.

• ---

  , 1981. The Interpretation of Frege's Philosophy. Harvard University Press.

• ---

  , 1991. Frege: Philosophy of Mathematics. Harvard University Press.
• Demopoulos, William, 1995. "Frege's Philosophy of Mathematics". Harvard Univ. Press.

^{Explores the significance of Frege's theorem, and his mathematical and intellectural background.}

• Ferreira, F. and Wehmeier, K., 2002, "On the consistency of the Delta-1-1-CA fragment of Frege's Grundgesetze," Journal of Philosophic Logic 31: 301-11.
• Grattan-Guinness, Ivor, 2000. The Search for Mathematical Roots 1870-1940. Princeton University Press.

^{Fair to the mathematician, less so to the philosopher.}

• Gillies, Douglas A., 1982. Frege, Dedekind, and Peano on the foundations of arithmetic. Assen, Netherlands: Van Gorcum.
• Hatcher, William, 1982. The Logical Foundations of Mathematics. Pergamon.

^{Chpt. 3 recasts the system of the Grundgesetze in modern notation, and derives the Peano axioms in this system using natural deduction.}

• Hill, C. O., 1991. Word and Object in Husserl, Frege and Russell: The Roots of Twentieth-Century Philosophy. Athens OH: Ohio University Press.

• ---

  , and Rosado Haddock, G. E., 2000. Husserl or Frege: Meaning, Objectivity, and Mathematics. Open Court.

^{On the Frege-Husserl-Cantor triangle.}

• Kenny, Anthony, 1995. Frege - An introduction to the founder of modern analytic philosophy. Penguin Books.

^{Excellent introduction and overview of Frege's philosophy for the philosopher and the non-philosopher.}

• Klemke, E.D., ed., 1968. Essays on Frege. University of Illinois Press.

^{Contains a total of thirty-one essays on Frege's work by prominent philosophers; essays divided into three part subject matter sections: 1. 'Frege's Ontology', 2. 'Frege's Semantics', and 3. 'Frege's Logic and Philosophy of Mathematics'.}

• Rosado Haddock, Guillermo E., 2006. A Critical Introduction to the Philosophy of Gottlob Frege. Ashgate Publishing.
• Sisti, Nicola, 2005. Il Programma Logicista di Frege e il Tema delle Definizioni. Franco Angeli.

^{Analyses and explains Frege's thought on definitions.}

• Sluga, Hans, 1980. Gottlob Frege. Routledge.
• Smith, Leslie, 1999. "What Piaget Learned from Frege." Developmental Review 19(1): 133-153.

^{An examination of why Frege first appears in Piaget's writings in 1949, twenty-five years after he began publishing on logic and epistemology.}

• Weiner, Joan, 1990. Frege in Perspective. Cornell University Press.
• Wright, Crispin, 1983. Frege's Conception of Numbers as Objects. Aberdeen University Press.

^{Written from the viewpoint of a modern philosopher of language and logic, contains a systematic exposition and a scope-restricted defense of Frege's Grundlagen conception of numbers.}

External links

• A comprehensive guide to Fregean material available on the web by Brian Carver.
• Stanford Encyclopedia of Philosophy:
• "Gottlob Frege" -- by Edward Zalta.
• "Frege's Logic, Theorem, and Foundations for Arithmetic" -- by Edward Zalta
• Internet Encyclopedia of Philosophy:
• Gottlob Frege -- by Kevin C. Klement.
• Frege and Language -- by Dorothea Lotter.
• Metaphysics Research Lab: Gottlob Frege.
• Frege on Being, Existence and Truth.
• O'Connor, John J; Edmund F. Robertson "Gottlob Frege". MacTutor History of Mathematics archive.  
• Begriff, a LaTeX package for typesetting Frege's logic notation.

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Persondata
NAME	Frege, Friedrich Ludwig Gottlob
ALTERNATIVE NAMES	Frege, Gottlob
SHORT DESCRIPTION	Important German logician and philosopher
DATE OF BIRTH	November 8, 1848
PLACE OF BIRTH	Wismar
DATE OF DEATH	July 26, 1925
PLACE OF DEATH	Bad Kleinen