Combining Texts

All the ideas for 'fragments/reports', 'On Formally Undecidable Propositions' and 'Vagueness and Contradiction'

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40 ideas

1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
The paradox of analysis says that any conceptual analysis must be either trivial or false [Sorensen]
2. Reason / B. Laws of Thought / 1. Laws of Thought
Two long understandable sentences can have an unintelligible conjunction [Sorensen]
3. Truth / B. Truthmakers / 6. Making Negative Truths
If nothing exists, no truthmakers could make 'Nothing exists' true [Sorensen]
3. Truth / B. Truthmakers / 12. Rejecting Truthmakers
Which toothbrush is the truthmaker for 'buy one, get one free'? [Sorensen]
3. Truth / F. Semantic Truth / 1. Tarski's Truth / a. Tarski's truth definition
Prior to Gödel we thought truth in mathematics consisted in provability [Gödel, by Quine]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
Gödel show that the incompleteness of set theory was a necessity [Gödel, by Hallett,M]
5. Theory of Logic / D. Assumptions for Logic / 1. Bivalence
No attempt to deny bivalence has ever been accepted [Sorensen]
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
We now see that generalizations use variables rather than abstract entities [Sorensen]
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
The limitations of axiomatisation were revealed by the incompleteness theorems [Gödel, by Koellner]
5. Theory of Logic / K. Features of Logics / 2. Consistency
Second Incompleteness: nice theories can't prove their own consistency [Gödel, by Smith,P]
5. Theory of Logic / K. Features of Logics / 3. Soundness
If soundness can't be proved internally, 'reflection principles' can be added to assert soundness [Gödel, by Halbach/Leigh]
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
Gödel's First Theorem sabotages logicism, and the Second sabotages Hilbert's Programme [Smith,P on Gödel]
The undecidable sentence can be decided at a 'higher' level in the system [Gödel]
5. Theory of Logic / L. Paradox / 3. Antinomies
Denying problems, or being romantically defeated by them, won't make them go away [Sorensen]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
Banning self-reference would outlaw 'This very sentence is in English' [Sorensen]
6. Mathematics / A. Nature of Mathematics / 1. Mathematics
There can be no single consistent theory from which all mathematical truths can be derived [Gödel, by George/Velleman]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Gödel showed that arithmetic is either incomplete or inconsistent [Gödel, by Rey]
First Incompleteness: arithmetic must always be incomplete [Gödel, by Smith,P]
Arithmetical truth cannot be fully and formally derived from axioms and inference rules [Gödel, by Nagel/Newman]
Gödel's Second says that semantic consequence outruns provability [Gödel, by Hanna]
First Incompleteness: a decent consistent system is syntactically incomplete [Gödel, by George/Velleman]
Second Incompleteness: a decent consistent system can't prove its own consistency [Gödel, by George/Velleman]
There is a sentence which a theory can show is true iff it is unprovable [Gödel, by Smith,P]
'This system can't prove this statement' makes it unprovable either way [Gödel, by Clegg]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism
Realists are happy with impredicative definitions, which describe entities in terms of other existing entities [Gödel, by Shapiro]
7. Existence / D. Theories of Reality / 10. Vagueness / c. Vagueness as ignorance
Vague words have hidden boundaries [Sorensen]
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
An offer of 'free coffee or juice' could slowly shift from exclusive 'or' to inclusive 'or' [Sorensen]
12. Knowledge Sources / A. A Priori Knowledge / 1. Nature of the A Priori
It is propositional attitudes which can be a priori, not the propositions themselves [Sorensen]
Attributing apriority to a proposition is attributing a cognitive ability to someone [Sorensen]
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / d. Secondary qualities
The colour bands of the spectrum arise from our biology; they do not exist in the physics [Sorensen]
12. Knowledge Sources / B. Perception / 5. Interpretation
We are unable to perceive a nose (on the back of a mask) as concave [Sorensen]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / b. Pro-coherentism
Bayesians build near-certainty from lots of reasonably probable beliefs [Sorensen]
13. Knowledge Criteria / D. Scepticism / 3. Illusion Scepticism
Illusions are not a reason for skepticism, but a source of interesting scientific information [Sorensen]
17. Mind and Body / C. Functionalism / 2. Machine Functionalism
Basic logic can be done by syntax, with no semantics [Gödel, by Rey]
19. Language / A. Nature of Meaning / 5. Meaning as Verification
The negation of a meaningful sentence must itself be meaningful [Sorensen]
19. Language / D. Propositions / 4. Mental Propositions
Propositions are what settle problems of ambiguity in sentences [Sorensen]
25. Social Practice / A. Freedoms / 4. Free market
I can buy any litre of water, but not every litre of water [Sorensen]
26. Natural Theory / A. Speculations on Nature / 5. Infinite in Nature
Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius]
27. Natural Reality / G. Biology / 3. Evolution
Archelaus said life began in a primeval slime [Archelaus, by Schofield]
28. God / A. Divine Nature / 4. Divine Contradictions
God cannot experience unwanted pain, so God cannot understand human beings [Sorensen]