Combining Texts

All the ideas for 'The Concept of a Person', 'On Formally Undecidable Propositions' and 'Remarks on the Foundations of Mathematics'

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27 ideas

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]
3. Truth / H. Deflationary Truth / 1. Redundant Truth
'It is true that this follows' means simply: this follows [Wittgenstein]
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 / 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]
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 / 6. Logicism / a. Early logicism
Two and one making three has the necessity of logical inference [Wittgenstein]
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]
15. Nature of Minds / A. Nature of Mind / 4. Other Minds / b. Scepticism of other minds
Maybe induction could never prove the existence of something unobservable [Ayer]
16. Persons / B. Nature of the Self / 1. Self and Consciousness
Consciousness must involve a subject, and only bodies identify subjects [Ayer]
16. Persons / B. Nature of the Self / 7. Self and Body / a. Self needs body
People own conscious states because they are causally related to the identifying body [Ayer]
16. Persons / C. Self-Awareness / 3. Limits of Introspection
We identify experiences by their owners, so we can't define owners by their experiences [Ayer]
16. Persons / D. Continuity of the Self / 2. Mental Continuity / a. Memory is Self
Memory is the best proposal as what unites bundles of experiences [Ayer]
Not all exerience can be remembered, as this would produce an infinite regress [Ayer]
16. Persons / D. Continuity of the Self / 6. Body sustains Self
Personal identity can't just be relations of experiences, because the body is needed to identify them [Ayer]
17. Mind and Body / C. Functionalism / 2. Machine Functionalism
Basic logic can be done by syntax, with no semantics [Gödel, by Rey]