Combining Texts

All the ideas for 'fragments/reports', 'On Formally Undecidable Propositions' and 'The Condemnation of 1277'

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27 ideas

1. Philosophy / D. Nature of Philosophy / 4. Divisions of Philosophy
Six parts: dialectic, rhetoric, ethics, politics, physics, theology [Cleanthes, by Diog. Laertius]
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 / 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 / 10. Constructivism / d. Predicativism
Realists are happy with impredicative definitions, which describe entities in terms of other existing entities [Gödel, by Shapiro]
10. Modality / B. Possibility / 1. Possibility
In future, only logical limits can be placed on divine omnipotence [Anon (Par), by Boulter]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / f. Foundationalism critique
It is heresy to require self-evident foundational principles in order to be certain [Anon (Par)]
17. Mind and Body / A. Mind-Body Dualism / 8. Dualism of Mind Critique
Bodies interact with other bodies, and cuts cause pain, and shame causes blushing, so the soul is a body [Cleanthes, by Nemesius]
17. Mind and Body / C. Functionalism / 2. Machine Functionalism
Basic logic can be done by syntax, with no semantics [Gödel, by Rey]
17. Mind and Body / E. Mind as Physical / 1. Physical Mind
The soul suffers when the body hurts, creates redness from shame, and pallor from fear [Cleanthes]
25. Social Practice / E. Policies / 5. Education / d. Study of history
It is heresy to teach that history repeats every 36,000 years [Anon (Par)]
28. God / A. Divine Nature / 3. Divine Perfections
It is heresy to teach that natural impossibilities cannot even be achieved by God [Anon (Par)]
28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
It is heresy to teach that we can know God by his essence in this mortal life [Anon (Par)]
28. God / B. Proving God / 3. Proofs of Evidence / b. Teleological Proof
The ascending scale of living creatures requires a perfect being [Cleanthes, by Tieleman]