Combining Texts

All the ideas for 'Changes in Events and Changes in Things', 'Introduction to Mathematical Logic' and 'Notebooks 1914-1916'

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30 ideas

1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
18274 Analysis complicates a statement, but only as far as the complexity of its meaning [Wittgenstein]
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
16908 We can dispense with self-evidence, if language itself prevents logical mistakes [Jeshion on Wittgenstein]
17741 To determine the patterns in logic, one must identify its 'building blocks' [Walicki]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
18276 A statement's logical form derives entirely from its constituents [Wittgenstein]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
6563 'And' and 'not' are non-referring terms, which do not represent anything [Wittgenstein, by Fogelin]
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]
7. Existence / C. Structure of Existence / 6. Fundamentals / d. Logical atoms
23472 The sense of propositions relies on the world's basic logical structure [Wittgenstein]
7. Existence / D. Theories of Reality / 8. Facts / b. Types of fact
15201 That Queen Anne is dead is a 'general fact', not a fact about Queen Anne [Prior,AN]
10. Modality / A. Necessity / 2. Nature of Necessity
17742 Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki]
12. Knowledge Sources / A. A Priori Knowledge / 5. A Priori Synthetic
23500 My main problem is the order of the world, and whether it is knowable a priori [Wittgenstein]
16. Persons / B. Nature of the Self / 4. Presupposition of Self
22323 The philosophical I is the metaphysical subject, the limit - not a part of the world [Wittgenstein]
19. Language / A. Nature of Meaning / 2. Meaning as Mental
23481 Propositions assemble a world experimentally, like the model of a road accident [Wittgenstein]
25. Social Practice / F. Life Issues / 4. Suicide
4678 Absolute prohibitions are the essence of ethics, and suicide is the most obvious example [Wittgenstein]
27. Natural Reality / D. Time / 2. Passage of Time / e. Tensed (A) series
22899 'Thank goodness that's over' is not like 'thank goodness that happened on Friday' [Prior,AN]