Combining Texts

All the ideas for 'Philosophy of Language', 'The Mirage of Social Justice' and 'Introduction to Mathematical Logic'

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29 ideas

4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
17749 Post proved the consistency of propositional logic in 1921 [Walicki]
17765 Propositional language can only relate statements as the same or as different [Walicki]
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
17764 Boolean connectives are interpreted as functions on the set {1,0} [Walicki]
4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
15163 The interest of quantified modal logic is its metaphysical necessity and essentialism [Soames]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
17752 The empty set is useful for defining sets by properties, when the members are not yet known [Walicki]
17753 The empty set avoids having to take special precautions in case members vanish [Walicki]
4. Formal Logic / F. Set Theory ST / 6. Ordering in Sets
17759 Ordinals play the central role in set theory, providing the model of well-ordering [Walicki]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
17741 To determine the patterns in logic, one must identify its 'building blocks' [Walicki]
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / a. Descriptions
15158 Indefinite descriptions are quantificational in subject position, but not in predicate position [Soames]
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / c. Theory of definite descriptions
15157 Recognising the definite description 'the man' as a quantifier phrase, not a singular term, is a real insight [Soames]
5. Theory of Logic / G. Quantification / 7. Unorthodox Quantification
15156 The universal and existential quantifiers were chosen to suit mathematics [Soames]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
17747 A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
17748 The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
17763 Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki]
17761 A compact axiomatisation makes it possible to understand a field as a whole [Walicki]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
17757 Members of ordinals are ordinals, and also subsets of ordinals [Walicki]
17758 Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki]
17755 Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki]
17756 The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki]
17760 Two infinite ordinals can represent a single infinite cardinal [Walicki]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
17762 In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
17754 Inductive proof depends on the choice of the ordering [Walicki]
10. Modality / A. Necessity / 2. Nature of Necessity
17742 Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki]
10. Modality / A. Necessity / 5. Metaphysical Necessity
15161 There are more metaphysically than logically necessary truths [Soames]
15162 We understand metaphysical necessity intuitively, from ordinary life [Soames]
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
15152 To study meaning, study truth conditions, on the basis of syntax, and representation by the parts [Soames]
15153 Tarski's account of truth-conditions is too weak to determine meanings [Soames]
19. Language / D. Propositions / 4. Mental Propositions
15154 We should use cognitive states to explain representational propositions, not vice versa [Soames]
25. Social Practice / D. Justice / 1. Basis of justice
20543 'Social justice' is a confused idea, and inequalities need no justification [Hayek, by Swift]