Combining Texts

All the ideas for 'Existence and Quantification', 'Aenesidemus' and 'Introduction to Mathematical Logic'

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30 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
5745 Quine says quantified modal logic creates nonsense, bad ontology, and false essentialism [Melia on Quine]
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 / A. Overview of Logic / 7. Second-Order Logic
8789 Various strategies try to deal with the ontological commitments of second-order logic [Hale/Wright on Quine]
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]
7. Existence / A. Nature of Existence / 3. Being / b. Being and existence
16966 Philosophers tend to distinguish broad 'being' from narrower 'existence' - but I reject that [Quine]
7. Existence / A. Nature of Existence / 6. Criterion for Existence
16965 All we have of general existence is what existential quantifiers express [Quine]
7. Existence / D. Theories of Reality / 2. Realism
22014 Consciousness is not entirely representational, because there are pains, and the self [Schulze, by Pinkard]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / b. Commitment of quantifiers
16963 Existence is implied by the quantifiers, not by the constants [Quine]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / c. Commitment of predicates
16964 Theories are committed to objects of which some of its predicates must be true [Quine]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / d. Commitment of theories
4216 Express a theory in first-order predicate logic; its ontology is the types of bound variable needed for truth [Quine, by Lowe]
18966 Ontological commitment of theories only arise if they are classically quantified [Quine]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / e. Ontological commitment problems
14490 You can be implicitly committed to something without quantifying over it [Thomasson on Quine]
7. Existence / E. Categories / 1. Categories
16961 In formal terms, a category is the range of some style of variables [Quine]
10. Modality / A. Necessity / 2. Nature of Necessity
17742 Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki]