Combining Philosophers

All the ideas for Hermarchus, Amie L. Thomasson and Kurt Gdel

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62 ideas

2. Reason / A. Nature of Reason / 1. On Reason
For clear questions posed by reason, reason can also find clear answers [Gödel]
2. Reason / D. Definition / 8. Impredicative Definition
Impredicative Definitions refer to the totality to which the object itself belongs [Gödel]
3. Truth / B. Truthmakers / 12. Rejecting Truthmakers
Maybe analytic truths do not require truth-makers, as they place no demands on the world [Thomasson]
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 / C. Predicate Calculus PC / 3. Completeness of PC
Gödel proved the completeness of first order predicate logic in 1930 [Gödel, by Walicki]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
We perceive the objects of set theory, just as we perceive with our senses [Gödel]
Gödel show that the incompleteness of set theory was a necessity [Gödel, by Hallett,M]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / o. Axiom of Constructibility V = L
Gödel proved the classical relative consistency of the axiom V = L [Gödel, by Putnam]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / p. Axiom of Reducibility
In simple type theory the axiom of Separation is better than Reducibility [Gödel, by Linsky,B]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Gödel proved that first-order logic is complete, and second-order logic incomplete [Gödel, by Dummett]
5. Theory of Logic / A. Overview of Logic / 8. Logic of Mathematics
Mathematical Logic is a non-numerical branch of mathematics, and the supreme science [Gödel]
5. Theory of Logic / B. Logical Consequence / 6. Entailment
Analytical entailments arise from combinations of meanings and inference rules [Thomasson]
5. Theory of Logic / G. Quantification / 2. Domain of Quantification
Reference to a totality need not refer to a conjunction of all its elements [Gödel]
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
Originally truth was viewed with total suspicion, and only demonstrability was accepted [Gödel]
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 Theorems did not refute the claim that all good mathematical questions have answers [Gödel, by Koellner]
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 / K. Features of Logics / 8. Enumerability
A logical system needs a syntactical survey of all possible expressions [Gödel]
5. Theory of Logic / L. Paradox / 5. Paradoxes in Set Theory / a. Set theory paradoxes
Set-theory paradoxes are no worse than sense deception in physics [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 / A. Nature of Mathematics / 5. The Infinite / g. Continuum Hypothesis
The generalized Continuum Hypothesis asserts a discontinuity in cardinal numbers [Gödel]
The Continuum Hypothesis is not inconsistent with the axioms of set theory [Gödel, by Clegg]
If set theory is consistent, we cannot refute or prove the Continuum Hypothesis [Gödel, by Hart,WD]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Gödel eventually hoped for a generalised completeness theorem leaving nothing undecidable [Gödel, by Koellner]
The real reason for Incompleteness in arithmetic is inability to define truth in a language [Gödel]
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]
Some arithmetical problems require assumptions which transcend arithmetic [Gödel]
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / a. For mathematical platonism
Mathematical objects are as essential as physical objects are for perception [Gödel]
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
Basic mathematics is related to abstract elements of our empirical ideas [Gödel]
6. Mathematics / C. Sources of Mathematics / 10. Constructivism / d. Predicativism
Impredicative definitions are admitted into ordinary mathematics [Gödel]
Realists are happy with impredicative definitions, which describe entities in terms of other existing entities [Gödel, by Shapiro]
7. Existence / A. Nature of Existence / 6. Criterion for Existence
Existence might require playing a role in explanation, or in a causal story, or being composed in some way [Thomasson]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / a. Ontological commitment
Rival ontological claims can both be true, if there are analytic relationships between them [Thomasson]
7. Existence / D. Theories of Reality / 11. Ontological Commitment / d. Commitment of theories
Theories do not avoid commitment to entities by avoiding certain terms or concepts [Thomasson]
9. Objects / A. Existence of Objects / 1. Physical Objects
Ordinary objects may be not indispensable, but they are nearly unavoidable [Thomasson]
The simple existence conditions for objects are established by our practices, and are met [Thomasson]
9. Objects / A. Existence of Objects / 6. Nihilism about Objects
It is analytic that if simples are arranged chair-wise, then there is a chair [Thomasson, by Hofweber]
Eliminativists haven't found existence conditions for chairs, beyond those of the word 'chair' [Thomasson]
Ordinary objects are rejected, to avoid contradictions, or for greater economy in thought [Thomasson]
To individuate people we need conventions, but conventions are made up by people [Thomasson]
9. Objects / B. Unity of Objects / 1. Unifying an Object / c. Unity as conceptual
Wherever an object exists, there are intrinsic properties instantiating every modal profile [Thomasson]
9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
If the statue and the lump are two objects, they require separate properties, so we could add their masses [Thomasson]
Given the similarity of statue and lump, what could possibly ground their modal properties? [Thomasson]
9. Objects / F. Identity among Objects / 6. Identity between Objects
Identity claims between objects are only well-formed if the categories are specified [Thomasson]
Identical entities must be of the same category, and meet the criteria for the category [Thomasson]
10. Modality / C. Sources of Modality / 3. Necessity by Convention
Modal Conventionalism says modality is analytic, not intrinsic to the world, and linguistic [Thomasson]
12. Knowledge Sources / E. Direct Knowledge / 1. Common Sense
A chief task of philosophy is making reflective sense of our common sense worldview [Thomasson]
17. Mind and Body / C. Functionalism / 2. Machine Functionalism
Basic logic can be done by syntax, with no semantics [Gödel, by Rey]
19. Language / B. Reference / 3. Direct Reference / b. Causal reference
How can causal theories of reference handle nonexistence claims? [Thomasson]
Pure causal theories of reference have the 'qua problem', of what sort of things is being referred to [Thomasson]
19. Language / E. Analyticity / 1. Analytic Propositions
Analyticity is revealed through redundancy, as in 'He bought a house and a building' [Thomasson]
25. Social Practice / F. Life Issues / 6. Animal Rights
Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley]