Combining Philosophers

All the ideas for Menedemus, Gregory L. Murphy and Kurt Gdel

expand these ideas     |    start again     |     specify just one area for these philosophers


65 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 / 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 / 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]
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 showed that arithmetic is either incomplete or inconsistent [Gödel, by Rey]
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]
12. Knowledge Sources / B. Perception / 5. Interpretation
Research shows perceptual discrimination is sharper at category boundaries [Murphy]
14. Science / C. Induction / 1. Induction
Induction is said to just compare properties of categories, but the type of property also matters [Murphy]
17. Mind and Body / C. Functionalism / 2. Machine Functionalism
Basic logic can be done by syntax, with no semantics [Gödel, by Rey]
18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts
The main theories of concepts are exemplar, prototype and knowledge [Murphy]
18. Thought / D. Concepts / 4. Structure of Concepts / c. Classical concepts
The classical definitional approach cannot distinguish typical and atypical category members [Murphy]
Classical concepts follow classical logic, but concepts in real life don't work that way [Murphy]
Classical concepts are transitive hierarchies, but actual categories may be intransitive [Murphy]
The classical core is meant to be the real concept, but actually seems unimportant [Murphy]
The theoretical and practical definitions for the classical view are very hard to find [Murphy]
18. Thought / D. Concepts / 4. Structure of Concepts / d. Concepts as prototypes
There is no 'ideal' bird or dog, and prototypes give no information about variability [Murphy]
Prototypes are unified representations of the entire category (rather than of members) [Murphy]
The prototype theory uses observed features, but can't include their construction [Murphy]
The prototype theory handles hierarchical categories and combinations of concepts well [Murphy]
Prototypes theory of concepts is best, as a full description with weighted typical features [Murphy]
Learning concepts is forming prototypes with a knowledge structure [Murphy]
18. Thought / D. Concepts / 4. Structure of Concepts / e. Concepts from exemplars
The exemplar view of concepts says 'dogs' is the set of dogs I remember [Murphy]
Children using knowing and essentialist categories doesn't fit the exemplar view [Murphy]
Exemplar theory struggles with hierarchical classification and with induction [Murphy]
Conceptual combination must be compositional, and can't be built up from exemplars [Murphy]
The concept of birds from exemplars must also be used in inductions about birds [Murphy]
The most popular theories of concepts are based on prototypes or exemplars [Murphy]
18. Thought / D. Concepts / 4. Structure of Concepts / f. Theory theory of concepts
We do not learn concepts in isolation, but as an integrated part of broader knowledge [Murphy]
Concepts with familiar contents are easier to learn [Murphy]
Some knowledge is involved in instant use of categories, other knowledge in explanations [Murphy]
People categorise things consistent with their knowledge, even rejecting some good evidence [Murphy]
23. Ethics / A. Egoism / 1. Ethical Egoism
The greatest good is not the achievement of desire, but to desire what is proper [Menedemus, by Diog. Laertius]