Combining Texts

All the ideas for 'Physics and Philosophy', 'Consistency and realism (with 1972 note)' and 'On Formally Undecidable Propositions'

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36 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]
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 / 4. Mathematical Empiricism / b. Indispensability of mathematics
If it can't be expressed mathematically, it can't occur in nature? [Heisenberg]
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 / 2. Realism
Quantum theory shows that exact science does not need dogmatic realism [Heisenberg]
7. Existence / D. Theories of Reality / 4. Anti-realism
Quantum theory does not introduce minds into atomic events [Heisenberg]
8. Modes of Existence / C. Powers and Dispositions / 2. Powers as Basic
A 'probability wave' is a quantitative version of Aristotle's potential, a mid-way type of reality [Heisenberg]
9. Objects / B. Unity of Objects / 2. Substance / a. Substance
We can retain the idea of 'substance', as indestructible mass or energy [Heisenberg]
9. Objects / C. Structure of Objects / 2. Hylomorphism / b. Form as principle
Basic particles have a mathematical form, which is more important than their substance [Heisenberg]
14. Science / D. Explanation / 2. Types of Explanation / e. Lawlike explanations
We give a mathematical account of a system of natural connections in order to clarify them [Heisenberg]
17. Mind and Body / C. Functionalism / 2. Machine Functionalism
Basic logic can be done by syntax, with no semantics [Gödel, by Rey]
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / f. Ethical non-cognitivism
We tolerate inconsistency in ethics but not in other beliefs (which reflect an independent order) [Williams,B, by Foot]
26. Natural Theory / D. Laws of Nature / 2. Types of Laws
Seven theories in science: mechanics, heat, electricity, quantum, particles, relativity, life [Heisenberg, by PG]
27. Natural Reality / A. Classical Physics / 2. Thermodynamics / a. Energy
Energy is that which moves, and is the substance from which everything is made [Heisenberg]
Energy is an unchanging substance, having many forms, and causing all change [Heisenberg]
27. Natural Reality / B. Modern Physics / 2. Electrodynamics / b. Fields
Maxwell introduced real fields, which transferred forces from point to point [Heisenberg]
27. Natural Reality / B. Modern Physics / 2. Electrodynamics / d. Quantum mechanics
Radiation interference needs waves, but radiation photoelectric effects needs particles [Heisenberg]
27. Natural Reality / B. Modern Physics / 4. Standard Model / a. Concept of matter
An atom's stability after collisions needs explaining (which Newton's mechanics can't do) [Heisenberg]
Position is complementary to velocity or momentum, so the whole system is indeterminate [Heisenberg]
It was formerly assumed that electromagnetic waves could not be a reality in themselves [Heisenberg]
27. Natural Reality / C. Space / 4. Substantival Space
So-called 'empty' space is the carrier of geometry and kinematics [Heisenberg]
27. Natural Reality / D. Time / 3. Parts of Time / e. Present moment
In relativity the length of the 'present moment' is relative to distance from the observer [Heisenberg]