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{{Infobox_Philosopher |
region = Western Philosophy |
era = [19th-century philosophy, |
color = #B0C4DE |
image_name = Young frege.jpg|
image_caption = Friedrich Ludwig Gottlob Frege|
name = '''Friedrich Ludwig Gottlob Frege''' |
birth =
November 8, [ |
death = 26 July, [ |
school_tradition = [Analytic philosophy |
main_interests = [Philosophy of mathematics, [mathematical logic, [Philosophy of language|
influenced = [Giuseppe Peano, [Bertrand Russell, [Rudolf Carnap, [Ludwig Wittgenstein, [Michael Dummett, [Edmund Husserl, and most of the [Analytic philosophy |
notable_ideas = [Predicate calculus, [Logicism, [Sense and reference |
-->
Friedrich Ludwig Gottlob Frege (
8 November 1848, Wismar, Grand Duchy of
Mecklenburg-Schwerin – 26 July 1925,
:de:Bad Kleinen,
Germany) () was a
Germany mathematics who became a
logician and philosophy. 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
Germany 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 people roots.
Already in his childhood, Frege encountered
philosophy 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 (school) 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,
Complex analysis,
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 plane (geometry),
Analytical mechanics,
Optics,
The physical foundations of mechanics); Hermann Schäffer (
Analytical geometry,
Applied physics,
Algebraic analysis,
On the telegraph and other electronics); and a famous philosopher,
Kuno Fischer (
The history of Kantianism 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
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
function (mathematics)s 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
axiomatization predicate logic, in large part thanks to his invention of
quantification, 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
Kurt Gödel Gödel's incompleteness theorem, 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 =
g(
x). In modern notation and terminology, let {
x] of the Predicate (logic)
Fx, and similarly for
Gx. Then Basic Law V says that the predicates
Fx and
Gx have the same extension iff ∀x ↔
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.
Michael 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 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 .
- 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 finitism or Mathematical constructivism 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
Frege is one of the founders of
analytic philosophy, mainly because of his contributions to the
philosophy of language, including the:
As a philosopher of mathematics, Frege attacked the
psychologism 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), posthumous work 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.
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.
- Michael Dummett, 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.
- Ivor Grattan-Guinness, 2000. The Search for Mathematical Roots 1870-1940. Princeton University Press.
Fair to the mathematician, less so to the philosopher.
- Douglas A. Gillies, 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.
- Anthony Kenny, 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.
- Hans Sluga, 1980. Gottlob Frege. Routledge.
- Smith, Leslie, 1999. "What Jean 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.
- Crispin Wright, 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.
-
- Begriff, a LaTeX package for typesetting Frege's logic notation.
{{Persondata] logician and philosophy|DATE OF BIRTH = November 8, 1848|DATE OF DEATH = [July 26, [1925-->
{{Infobox_Philosopher |
region = Western Philosophy |
era = [19th-century philosophy, |
color = #B0C4DE |
image_name = Young frege.jpg|
image_caption = Friedrich Ludwig Gottlob Frege|
name = '''Friedrich Ludwig Gottlob Frege''' |
birth = November 8, [ |
death = 26 July, [ |
school_tradition = [Analytic philosophy |
main_interests = [Philosophy of mathematics, [mathematical logic, [Philosophy of language|
influenced = [Giuseppe Peano, [Bertrand Russell, [Rudolf Carnap, [Ludwig Wittgenstein, [Michael Dummett, [Edmund Husserl, and most of the [Analytic philosophy |
notable_ideas = [Predicate calculus, [Logicism, [Sense and reference |
-->
Friedrich Ludwig Gottlob Frege (8 November 1848,
Wismar, Grand Duchy of Mecklenburg-Schwerin –
26 July 1925,
:de:Bad Kleinen, Germany) () was a
Germany mathematics who became a logician and
philosophy. 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
Germany 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 people roots.
Already in his childhood, Frege encountered
philosophy 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 (school) 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,
Complex analysis,
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 plane (geometry),
Analytical mechanics,
Optics,
The physical foundations of mechanics);
Hermann Schäffer (
Analytical geometry,
Applied physics,
Algebraic analysis,
On the telegraph and other electronics); and a famous philosopher,
Kuno Fischer (
The history of Kantianism 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
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
function (mathematics)s 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 axiomatization
predicate logic, in large part thanks to his invention of quantification, 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 Kurt Gödel
Gödel's incompleteness theorem, 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 =
g(
x). In modern notation and terminology, let {
x] of the Predicate (logic)
Fx, and similarly for
Gx. Then Basic Law V says that the predicates
Fx and
Gx have the same extension
iff ∀x ↔
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. Michael 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 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 .
- 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 finitism or Mathematical constructivism 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
Frege is one of the founders of
analytic philosophy, mainly because of his contributions to the
philosophy of language, including the:
As a philosopher of mathematics, Frege attacked the psychologism 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
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), posthumous work 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.
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.
- Michael Dummett, 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.
- Ivor Grattan-Guinness, 2000. The Search for Mathematical Roots 1870-1940. Princeton University Press.
Fair to the mathematician, less so to the philosopher.
- Douglas A. Gillies, 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.
- Anthony Kenny, 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.
- Hans Sluga, 1980. Gottlob Frege. Routledge.
- Smith, Leslie, 1999. "What Jean 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.
- Crispin Wright, 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.
-
- Begriff, a LaTeX package for typesetting Frege's logic notation.
{{Persondata] logician and philosophy|DATE OF BIRTH =
November 8,
1848|DATE OF DEATH = [July 26, [1925-->
Frege summary
Gottlob Frege (1848-1925) ... Frege was one of the founders of modern symbolic logic putting forward the view that mathematics is reducible to logic.
Gottlob Frege from FOLDOC
Frege, Gottlob ==> Gottlob Frege < person, history, philosophy, mathematics, logic, theory > (1848-1925) A mathematician who put mathematics on a new and more solid foundation.
Gottlob Frege from FOLDOC
Gottlob Frege < person, history, philosophy, mathematics, logic, theory > (1848-1925) A mathematician who put mathematics on a new and more solid foundation.
Gottlob Frege - Wikipedia, the free encyclopedia
Friedrich Ludwig Gottlob Frege (8 November 1848, Wismar, Grand Duchy of Mecklenburg-Schwerin – 26 July 1925, Bad Kleinen, Germany) (IPA: [ˈgɔtlop ˈfʁeːgə]) was a German ...
Gottlob Frege (Stanford Encyclopedia of Philosophy)
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Gottlob Frege
Short biography from the Metaphysics Research Lab at Stanford.
Frege
Frege I completed my doctorate, on Frege's theory of incomplete expressions, at Leeds University where I was supervised, until his retirement, by Peter Geach and then by Roger ...
Frege biography
Biography of Gottlob Frege (BB^Y-1925) ... Born: 8 Nov 1848 in Wismar, Mecklenburg-Schwerin (now Germany) Died: 26 July 1925 in Bad Kleinen, Germany
LPSG Frege, Russell & Wittgenstein
1. The Paper. Frege, Russell and Wittgenstein have had a unique and powerful influence on almost all aspects of twentieth century analytic philosophy.
Frege, Gottlob
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