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Type theory: The type theory is a restriction of formal systems to a kind of reference which prevents symbols of a level (of a type) from referring to symbols of the same level (the same type). This is intended to avoid paradoxes arising from a self-reference of the signs or expressions used. Original proposals for type theories are given by B. Russell (B. Russell, “Mathematical logic as based on the theory of types”, in American Journal of Mathematics, 30, 1908, pp. 222-262). See also self-reference, circularity, paradoxes, Russell's Paradox, branched type theory.

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Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments.

 
Author Item Summary Meta data
VII (e) 91ff
QuineVsType theory: 1) universal class: because the type theory only allows uniform types as elements of a class, the universal class V leads to an infinite series of quasi-universal classes, each for one type - 2) negation: ~x stops including all non-elements of x and only includes those non-elements that belong to the next lower level - 3) Zero class: even this accordingly leads to an infinite number of zero classes - 4) Boolean class algebra: is no longer applicable to classes in general, but is reproduced at each level - 5) Relational calculus: accordingly to be established new at every level - 6) arithmetic: the numbers cease to be uniform. At each level (type) there is a new 0, new 1, new 2, etc.
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IX 186
Definition ramified type theory/Russell/Quine: distinction of orders for statement functions whose arguments are of one single order - in order for two attributes with the same extension to be able to differ in terms of their orders, attributes with the same extension must be distinguished and be called attributes and not classes. - New: this becomes superfluous when we drop the branching.
Solution: context definition/Russell: we define class abstraction through context, thus "ε" remains the only basic concept apart from quantifiers, variables and statement-logical links. - Context definition for class abstraction: "yn ε {xn: Fxn}" stands for "∃z n + 1["xn(xn ε z n+1 Fxn) u yn ε z n + 1]".
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IX 191ff
Cumulative types/Set Theory/Quine: Type 0: Only L is of type 0 - type 1: L and {L} and nothing else - Type n: should generally include only this and the 2n sets that belong to type n-1 - in this way, every quantification only interprets a finite number of cases. Each closed expression can be mechanically tested on being true - that no longer works when the axiom of infinity is added.
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IX 198
Cumulative types/Quine: advantages: if we equate the zero classes of all class types, (~T0x u ~T0y u ∀w(w ε x ↔ w ε y) u x ε z) › y ε z is a single axiom, no longer an axiom scheme - in int "~T0x u ~T0y" avoids that the individuals L are identified with one another - we need individuals, but we identify them with their classes of one (see above) - but one exception: if x is an individual, "x ε x" shall be considered as true, (Above, "x ε y" became false if both were not objects of sequential types).
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IX 201
Cumulative Type Theory/Quine: individuals: identified with their classes of one - no longer elementless, have themselves as elements - therefore definite identity: a = b if a ≤ b ≤ a - zero classes of all types can now be identified (formerly: "No individuals" , "no classes", etc.)
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IX 204
Natural numbers/QuineVsRussell: his type theory even has problems with Frege’s numbers: perhaps the successor relation does not bring something new always: Example 5 is then the class of all classes from five individuals, assuming that there are only five individuals in that universe. So 5 in type 2 equals {ϑ1} ,then 6, or S"5, in type 5 equals {z1: ∃y0(y0 e z1 u z1 n _{y0} = ϑ1)}: this equals Λ², because "y ε z u z n _{y} = ϑ" is contradictory - but then 7, or S"6, equals S'Λ², which is reduced to Λ² - i.e. S'x = x when x equals 6 in type 2, provided that there are no more than five individuals - otherwise the theory of numbers would collapse.


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Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution.
The note [Author1]Vs[Author2] or [Author]Vs[term] is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition.

Quine I
W.V.O. Quine
Word and Object, Cambridge/MA 1960
German Edition:
Wort und Gegenstand Stuttgart 1980

Quine II
W.V.O. Quine
Theories and Things, Cambridge/MA 1986
German Edition:
Theorien und Dinge Frankfurt 1985

Quine III
W.V.O. Quine
Methods of Logic, 4th edition Cambridge/MA 1982
German Edition:
Grundzüge der Logik Frankfurt 1978

Quine V
W.V.O. Quine
The Roots of Reference, La Salle/Illinois 1974
German Edition:
Die Wurzeln der Referenz Frankfurt 1989

Quine VI
W.V.O. Quine
Pursuit of Truth, Cambridge/MA 1992
German Edition:
Unterwegs zur Wahrheit Paderborn 1995

Quine VII
W.V.O. Quine
From a logical point of view Cambridge, Mass. 1953

Quine VII (a)
W. V. A. Quine
On what there is
In
From a Logical Point of View, , Cambridge, MA 1953

Quine VII (b)
W. V. A. Quine
Two dogmas of empiricism
In
From a Logical Point of View, , Cambridge, MA 1953

Quine VII (c)
W. V. A. Quine
The problem of meaning in linguistics
In
From a Logical Point of View, , Cambridge, MA 1953

Quine VII (d)
W. V. A. Quine
Identity, ostension and hypostasis
In
From a Logical Point of View, , Cambridge, MA 1953

Quine VII (e)
W. V. A. Quine
New foundations for mathematical logic
In
From a Logical Point of View, , Cambridge, MA 1953

Quine VII (f)
W. V. A. Quine
Logic and the reification of universals
In
From a Logical Point of View, , Cambridge, MA 1953

Quine VII (g)
W. V. A. Quine
Notes on the theory of reference
In
From a Logical Point of View, , Cambridge, MA 1953

Quine VII (h)
W. V. A. Quine
Reference and modality
In
From a Logical Point of View, , Cambridge, MA 1953

Quine VII (i)
W. V. A. Quine
Meaning and existential inference
In
From a Logical Point of View, , Cambridge, MA 1953

Quine VIII
W.V.O. Quine
Designation and Existence, in: The Journal of Philosophy 36 (1939)
German Edition:
Bezeichnung und Referenz
In
Zur Philosophie der idealen Sprache, J. Sinnreich (Hg), München 1982

Quine IX
W.V.O. Quine
Set Theory and its Logic, Cambridge/MA 1963
German Edition:
Mengenlehre und ihre Logik Wiesbaden 1967

Quine X
W.V.O. Quine
The Philosophy of Logic, Cambridge/MA 1970, 1986
German Edition:
Philosophie der Logik Bamberg 2005

Quine XII
W.V.O. Quine
Ontological Relativity and Other Essays, New York 1969
German Edition:
Ontologische Relativität Frankfurt 2003

Quine XIII
Willard Van Orman Quine
Quiddities Cambridge/London 1987


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Ed. Martin Schulz, access date 2020-04-08
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