Combining Texts

All the ideas for 'Introduction to Mathematical Logic', 'In Defense of Essentialism' and 'Survival and Identity, with postscript'

expand these ideas     |    start again     |     specify just one area for these texts

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 / 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 / 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
17761 A compact axiomatisation makes it possible to understand a field as a whole [Walicki]
17763 Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
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]
17757 Members of ordinals are ordinals, and also subsets of ordinals [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]
9. Objects / A. Existence of Objects / 5. Individuation / e. Individuation by kind
14193 'Substance theorists' take modal properties as primitive, without structure, just falling under a sortal [Paul,LA]
14195 If an object's sort determines its properties, we need to ask what determines its sort [Paul,LA]
14196 Substance essentialism says an object is multiple, as falling under various different sortals [Paul,LA]
9. Objects / C. Structure of Objects / 8. Parts of Objects / b. Sums of parts
14198 Absolutely unrestricted qualitative composition would allow things with incompatible properties [Paul,LA]
9. Objects / D. Essence of Objects / 2. Types of Essence
14190 Deep essentialist objects have intrinsic properties that fix their nature; the shallow version makes it contextual [Paul,LA]
9. Objects / D. Essence of Objects / 6. Essence as Unifier
14191 Deep essentialists say essences constrain how things could change; modal profiles fix natures [Paul,LA]
9. Objects / D. Essence of Objects / 15. Against Essentialism
14192 Essentialism must deal with charges of arbitrariness, and failure to reduce de re modality [Paul,LA]
14197 An object's modal properties don't determine its possibilities [Paul,LA]
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 / 4. De re / De dicto modality
16079 De re modal predicates are ambiguous [Lewis, by Rudder Baker]
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
14189 'Modal realists' believe in many concrete worlds, 'actualists' in just this world, 'ersatzists' in abstract other worlds [Paul,LA]