Combining Texts

All the ideas for 'works', 'Aboutness' and 'Introduction to Mathematical Logic'

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35 ideas

3. Truth / A. Truth Problems / 5. Truth Bearers
A statement S is 'partly true' if it has some wholly true parts [Yablo]
4. Formal Logic / A. Syllogistic Logic / 2. Syllogistic Logic
An 'enthymeme' is an argument with an indispensable unstated assumption [Yablo]
4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
Post proved the consistency of propositional logic in 1921 [Walicki]
Propositional language can only relate statements as the same or as different [Walicki]
4. Formal Logic / B. Propositional Logic PL / 3. Truth Tables
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
The empty set is useful for defining sets by properties, when the members are not yet known [Walicki]
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
Ordinals play the central role in set theory, providing the model of well-ordering [Walicki]
4. Formal Logic / G. Formal Mereology / 3. Axioms of Mereology
y is only a proper part of x if there is a z which 'makes up the difference' between them [Yablo]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
To determine the patterns in logic, one must identify its 'building blocks' [Walicki]
5. Theory of Logic / F. Referring in Logic / 1. Naming / e. Empty names
'Pegasus doesn't exist' is false without Pegasus, yet the absence of Pegasus is its truthmaker [Yablo]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
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
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
A compact axiomatisation makes it possible to understand a field as a whole [Walicki]
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
Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki]
Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki]
The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki]
Two infinite ordinals can represent a single infinite cardinal [Walicki]
Members of ordinals are ordinals, and also subsets of ordinals [Walicki]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
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
Inductive proof depends on the choice of the ordering [Walicki]
6. Mathematics / C. Sources of Mathematics / 3. Mathematical Nominalism
A nominalist can assert statements about mathematical objects, as being partly true [Yablo]
9. Objects / C. Structure of Objects / 8. Parts of Objects / a. Parts of objects
Parthood lacks the restriction of kind which most relations have [Yablo]
10. Modality / A. Necessity / 2. Nature of Necessity
Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki]
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / b. Gettier problem
Gettier says you don't know if you are confused about how it is true [Yablo]
14. Science / B. Scientific Theories / 2. Aim of Science
A theory need not be true to be good; it should just be true about its physical aspects [Yablo]
14. Science / C. Induction / 5. Paradoxes of Induction / b. Raven paradox
If sentences point to different evidence, they must have different subject-matter [Yablo]
Most people say nonblack nonravens do confirm 'all ravens are black', but only a tiny bit [Yablo]
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
Sentence-meaning is the truth-conditions - plus factors responsible for them [Yablo]
19. Language / C. Assigning Meanings / 4. Compositionality
The content of an assertion can be quite different from compositional content [Yablo]
19. Language / C. Assigning Meanings / 6. Truth-Conditions Semantics
Truth-conditions as subject-matter has problems of relevance, short cut, and reversal [Yablo]
19. Language / F. Communication / 3. Denial
Not-A is too strong to just erase an improper assertion, because it actually reverses A [Yablo]
29. Religion / B. Monotheistic Religion / 4. Christianity / d. Heresy
Philosophers are the forefathers of heretics [Tertullian]
29. Religion / D. Religious Issues / 1. Religious Commitment / e. Fideism
I believe because it is absurd [Tertullian]