Combining Texts

All the ideas for 'Good and Evil', 'Alfred Tarski: life and logic' and 'Mathematics is Megethology'

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24 ideas

4. Formal Logic / F. Set Theory ST / 1. Set Theory
10807 Mathematics reduces to set theory, which reduces, with some mereology, to the singleton function [Lewis]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set
10809 We can accept the null set, but not a null class, a class lacking members [Lewis]
10812 The null set is not a little speck of sheer nothingness, a black hole in Reality [Lewis]
10811 The null set plays the role of last resort, for class abstracts and for existence [Lewis]
4. Formal Logic / F. Set Theory ST / 3. Types of Set / c. Unit (Singleton) Sets
10813 What on earth is the relationship between a singleton and an element? [Lewis]
10814 Are all singletons exact intrinsic duplicates? [Lewis]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
10147 The Axiom of Choice is consistent with the other axioms of set theory [Feferman/Feferman]
10148 Axiom of Choice: a set exists which chooses just one element each of any set of sets [Feferman/Feferman]
10149 Platonist will accept the Axiom of Choice, but others want criteria of selection or definition [Feferman/Feferman]
10150 The Trichotomy Principle is equivalent to the Axiom of Choice [Feferman/Feferman]
10146 Cantor's theories needed the Axiom of Choice, but it has led to great controversy [Feferman/Feferman]
4. Formal Logic / G. Formal Mereology / 1. Mereology
10806 Megethology is the result of adding plural quantification to mereology [Lewis]
5. Theory of Logic / E. Structures of Logic / 6. Relations in Logic
10816 We can use mereology to simulate quantification over relations [Lewis]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
10158 A structure is a 'model' when the axioms are true. So which of the structures are models? [Feferman/Feferman]
10162 Tarski and Vaught established the equivalence relations between first-order structures [Feferman/Feferman]
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
10159 Löwenheim-Skolem Theorem, and Gödel's completeness of first-order logic, the earliest model theory [Feferman/Feferman]
10160 Löwenheim-Skolem says if the sentences are countable, so is the model [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 4. Completeness
10161 If a sentence holds in every model of a theory, then it is logically derivable from the theory [Feferman/Feferman]
5. Theory of Logic / K. Features of Logics / 7. Decidability
10156 'Recursion theory' concerns what can be solved by computing machines [Feferman/Feferman]
10155 Both Principia Mathematica and Peano Arithmetic are undecidable [Feferman/Feferman]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
10808 Mathematics is generalisations about singleton functions [Lewis]
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / e. Structuralism critique
10815 We don't need 'abstract structures' to have structural truths about successor functions [Lewis]
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
10810 I say that absolutely any things can have a mereological fusion [Lewis]
22. Metaethics / C. The Good / 1. Goodness / a. Form of the Good
22489 'Good' is an attributive adjective like 'large', not predicative like 'red' [Geach, by Foot]