Dependencies Between Quantifiers Vs. Dependencies Between Variables
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Gabriel Sandu
Abstract
I will argue that the most significant role of the logic of first-order quantifiers lies in its power to express functional dependencies and independencies between variables. The dependence of a variable x on another variable y has been standardly expressed by the formal dependence of a quantifier Qx on another quantifier Qy, which, in turn, is expressed by the former being in the syntactical scope of the latter. First-order logic, where scopes are required to be nested, cannot express all the possible patterns of dependence and independence between variables. To overcome this problem, two solutions have been proposed: to allow for more patterns of dependence and independence between quantifiers (Independence- Friendly (IF) logic); to express explicitly dependencies and independencies of variables (Dependence logic, Independence logic, etc). In both approaches the truth of a sentence amounts to the existence of appropriate “witness individuals” (Skolem functions).We have here a connection between the truth-conditions of quantified sentences and the existence of all the functions which produce these witness individuals. Hintikka has repeatedly argued that these functions codify winning strategies in certain (semantical) games and emphasized their connection to Wittgenstein’s language games. In my contribution I will look at the interesting perspective that language games open for the discussion of logic in general. Some of these points have been discussed in Hintikka/Sandu 2007.
Abstract
I will argue that the most significant role of the logic of first-order quantifiers lies in its power to express functional dependencies and independencies between variables. The dependence of a variable x on another variable y has been standardly expressed by the formal dependence of a quantifier Qx on another quantifier Qy, which, in turn, is expressed by the former being in the syntactical scope of the latter. First-order logic, where scopes are required to be nested, cannot express all the possible patterns of dependence and independence between variables. To overcome this problem, two solutions have been proposed: to allow for more patterns of dependence and independence between quantifiers (Independence- Friendly (IF) logic); to express explicitly dependencies and independencies of variables (Dependence logic, Independence logic, etc). In both approaches the truth of a sentence amounts to the existence of appropriate “witness individuals” (Skolem functions).We have here a connection between the truth-conditions of quantified sentences and the existence of all the functions which produce these witness individuals. Hintikka has repeatedly argued that these functions codify winning strategies in certain (semantical) games and emphasized their connection to Wittgenstein’s language games. In my contribution I will look at the interesting perspective that language games open for the discussion of logic in general. Some of these points have been discussed in Hintikka/Sandu 2007.
Chapters in this book
- Frontmatter I
- Contents V
- Preface IX
-
Part I: Philosophy of Logic
- Link’s Revenge: A Case Study in Natural Language Mereology 3
- Universal Translatability: An Optimality- Based Justification of (Classical) Logic 37
- Invariance and Necessity 55
- Translations Between Logics: A Survey 71
- On the Relation of Logic to Metalogic 91
- Free Logic and the Quantified Argument Calculus 105
- Dependencies Between Quantifiers Vs. Dependencies Between Variables 117
- Three Types and Traditions of Logic: Syllogistic, Calculus and Predicate Logic 133
- Truth, Paradox, and the Procedural Conception of Fregean Sense 153
- Wittgenstein and Frege on Assertion 169
- Assertions and Their Justification: Demonstration and Self-Evidence 183
- Surprises in Logic: When Dynamic Formality Meets Interactive Compositionality 197
-
Part II: Philosophy of Mathematics
- Neologicist Foundations: Inconsistent Abstraction Principles and Part-Whole 215
- What Hilbert and Bernays Meant by “Finitism” 249
- Wittgenstein and Turing 263
- Remarks on Two Papers of Paul Bernays 297
- The Significance of the Curry-Howard Isomorphism 313
- Reductions of Mathematics: Foundation or Horizon? 327
- What Are the Axioms for Numbers and Who Invented Them? 343
-
Part III: Wittgenstein
- Following a Rule: Waismann’s Variation 359
- Propositions in Wittgenstein and Ramsey 375
- An Unexpected Feature of Classical Propositional Logic in the Tractatus 385
- Ontology in Tractatus Logico-Philosophicus: A Topological Approach 397
- Adding 4.0241 to TLP 415
- Understanding Wittgenstein’s Wood Sellers 429
- On the Infinite, In-Potentia: Discovery of the Hidden Revision of Philosophical Investigations and Its Relation to TS 209 Through the Eyes of Wittgensteinian Mathematics 441
- Incomplete Pictures and Specific Forms: Wittgenstein Around 1930 457
- „Man kann die Menschen nicht zum Guten führen“ – Zur Logik des moralischen Urteils bei Wittgenstein und Hegel 473
- Der Status mathematischer und religiöser Sätze bei Wittgenstein 485
- Gutes Sehen 499
- Wittgenstein’s Conjecture 515
- Index of Names 535
- Index of Subjects 539
Chapters in this book
- Frontmatter I
- Contents V
- Preface IX
-
Part I: Philosophy of Logic
- Link’s Revenge: A Case Study in Natural Language Mereology 3
- Universal Translatability: An Optimality- Based Justification of (Classical) Logic 37
- Invariance and Necessity 55
- Translations Between Logics: A Survey 71
- On the Relation of Logic to Metalogic 91
- Free Logic and the Quantified Argument Calculus 105
- Dependencies Between Quantifiers Vs. Dependencies Between Variables 117
- Three Types and Traditions of Logic: Syllogistic, Calculus and Predicate Logic 133
- Truth, Paradox, and the Procedural Conception of Fregean Sense 153
- Wittgenstein and Frege on Assertion 169
- Assertions and Their Justification: Demonstration and Self-Evidence 183
- Surprises in Logic: When Dynamic Formality Meets Interactive Compositionality 197
-
Part II: Philosophy of Mathematics
- Neologicist Foundations: Inconsistent Abstraction Principles and Part-Whole 215
- What Hilbert and Bernays Meant by “Finitism” 249
- Wittgenstein and Turing 263
- Remarks on Two Papers of Paul Bernays 297
- The Significance of the Curry-Howard Isomorphism 313
- Reductions of Mathematics: Foundation or Horizon? 327
- What Are the Axioms for Numbers and Who Invented Them? 343
-
Part III: Wittgenstein
- Following a Rule: Waismann’s Variation 359
- Propositions in Wittgenstein and Ramsey 375
- An Unexpected Feature of Classical Propositional Logic in the Tractatus 385
- Ontology in Tractatus Logico-Philosophicus: A Topological Approach 397
- Adding 4.0241 to TLP 415
- Understanding Wittgenstein’s Wood Sellers 429
- On the Infinite, In-Potentia: Discovery of the Hidden Revision of Philosophical Investigations and Its Relation to TS 209 Through the Eyes of Wittgensteinian Mathematics 441
- Incomplete Pictures and Specific Forms: Wittgenstein Around 1930 457
- „Man kann die Menschen nicht zum Guten führen“ – Zur Logik des moralischen Urteils bei Wittgenstein und Hegel 473
- Der Status mathematischer und religiöser Sätze bei Wittgenstein 485
- Gutes Sehen 499
- Wittgenstein’s Conjecture 515
- Index of Names 535
- Index of Subjects 539