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All the ideas for 'Intro to Gödel's Theorems', 'Category Mistakes' and 'Does Conceivability Entail Possibility?'

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97 ideas

2. Reason / F. Fallacies / 8. Category Mistake / a. Category mistakes
People have dreams which involve category mistakes [Magidor]
Category mistakes are either syntactic, semantic, or pragmatic [Magidor]
2. Reason / F. Fallacies / 8. Category Mistake / b. Category mistake as syntactic
Category mistakes as syntactic needs a huge number of fine-grained rules [Magidor]
Embedded (in 'he said that…') category mistakes show syntax isn't the problem [Magidor]
Category mistakes seem to be universal across languages [Magidor]
2. Reason / F. Fallacies / 8. Category Mistake / c. Category mistake as semantic
Two good sentences should combine to make a good sentence, but that might be absurd [Magidor]
The normal compositional view makes category mistakes meaningful [Magidor]
If a category mistake is synonymous across two languages, that implies it is meaningful [Magidor]
Category mistakes are meaningful, because metaphors are meaningful category mistakes [Magidor]
A good explanation of why category mistakes sound wrong is that they are meaningless [Magidor]
If a category mistake has unimaginable truth-conditions, then it seems to be meaningless [Magidor]
Category mistakes are neither verifiable nor analytic, so verificationism says they are meaningless [Magidor]
Category mistakes play no role in mental life, so conceptual role semantics makes them meaningless [Magidor]
Maybe when you say 'two is green', the predicate somehow fails to apply? [Magidor]
If category mistakes aren't syntax failure or meaningless, maybe they just lack a truth-value? [Magidor]
2. Reason / F. Fallacies / 8. Category Mistake / d. Category mistake as pragmatic
Category mistakes suffer from pragmatic presupposition failure (which is not mere triviality) [Magidor]
In 'two is green', 'green' has a presupposition of being coloured [Magidor]
Category mistakes because of presuppositions still have a truth value (usually 'false') [Magidor]
'Numbers are coloured and the number two is green' seems to be acceptable [Magidor]
Maybe the presuppositions of category mistakes are the abilities of things? [Magidor]
2. Reason / F. Fallacies / 8. Category Mistake / e. Category mistake as ontological
The presuppositions in category mistakes reveal nothing about ontology [Magidor]
4. Formal Logic / E. Nonclassical Logics / 8. Intensional Logic
Intensional logic maps logical space, showing which predicates are compatible or incompatible [Magidor]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
There cannot be a set theory which is complete [Smith,P]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Second-order arithmetic can prove new sentences of first-order [Smith,P]
5. Theory of Logic / E. Structures of Logic / 5. Functions in Logic
A 'total function' maps every element to one element in another set [Smith,P]
An argument is a 'fixed point' for a function if it is mapped back to itself [Smith,P]
Two functions are the same if they have the same extension [Smith,P]
A 'partial function' maps only some elements to another set [Smith,P]
The 'range' of a function is the set of elements in the output set created by the function [Smith,P]
5. Theory of Logic / E. Structures of Logic / 7. Predicates in Logic
The Comprehension Schema says there is a property only had by things satisfying a condition [Smith,P]
5. Theory of Logic / E. Structures of Logic / 8. Theories in Logic
A 'theorem' of a theory is a sentence derived from the axioms using the proof system [Smith,P]
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
A 'natural deduction system' has no axioms but many rules [Smith,P]
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
No nice theory can define truth for its own language [Smith,P]
5. Theory of Logic / J. Model Theory in Logic / 2. Isomorphisms
A 'bijective' function has one-to-one correspondence in both directions [Smith,P]
A 'surjective' ('onto') function creates every element of the output set [Smith,P]
An 'injective' ('one-to-one') function creates a distinct output element from each original [Smith,P]
5. Theory of Logic / K. Features of Logics / 3. Soundness
If everything that a theory proves is true, then it is 'sound' [Smith,P]
Soundness is true axioms and a truth-preserving proof system [Smith,P]
A theory is 'sound' iff every theorem is true (usually from true axioms and truth-preservation) [Smith,P]
5. Theory of Logic / K. Features of Logics / 4. Completeness
A theory is 'negation complete' if it proves all sentences or their negation [Smith,P]
'Complete' applies both to whole logics, and to theories within them [Smith,P]
A theory is 'negation complete' if one of its sentences or its negation can always be proved [Smith,P]
5. Theory of Logic / K. Features of Logics / 5. Incompleteness
Two routes to Incompleteness: semantics of sound/expressible, or syntax of consistency/proof [Smith,P]
5. Theory of Logic / K. Features of Logics / 7. Decidability
A theory is 'decidable' if all of its sentences could be mechanically proved [Smith,P]
Any consistent, axiomatized, negation-complete formal theory is decidable [Smith,P]
'Effective' means simple, unintuitive, independent, controlled, dumb, and terminating [Smith,P]
5. Theory of Logic / K. Features of Logics / 8. Enumerability
A set is 'enumerable' is all of its elements can result from a natural number function [Smith,P]
A set is 'effectively enumerable' if a computer could eventually list every member [Smith,P]
A finite set of finitely specifiable objects is always effectively enumerable (e.g. primes) [Smith,P]
The set of ordered pairs of natural numbers <i,j> is effectively enumerable [Smith,P]
The thorems of a nice arithmetic can be enumerated, but not the truths (so they're diffferent) [Smith,P]
5. Theory of Logic / K. Features of Logics / 9. Expressibility
Being 'expressible' depends on language; being 'capture/represented' depends on axioms and proof system [Smith,P]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / a. Numbers
For primes we write (x not= 1 ∧ ∀u∀v(u x v = x → (u = 1 ∨ v = 1))) [Smith,P]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
The reals contain the naturals, but the theory of reals doesn't contain the theory of naturals [Smith,P]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / f. Arithmetic
The truths of arithmetic are just true equations and their universally quantified versions [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
All numbers are related to zero by the ancestral of the successor relation [Smith,P]
The number of Fs is the 'successor' of the Gs if there is a single F that isn't G [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / b. Baby arithmetic
Baby arithmetic covers addition and multiplication, but no general facts about numbers [Smith,P]
Baby Arithmetic is complete, but not very expressive [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / c. Robinson arithmetic
Robinson Arithmetic 'Q' has basic axioms, quantifiers and first-order logic [Smith,P]
Robinson Arithmetic (Q) is not negation complete [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
Natural numbers have zero, unique successors, unending, no circling back, and no strays [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / f. Mathematical induction
The logic of arithmetic must quantify over properties of numbers to handle induction [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / g. Incompleteness of Arithmetic
Incompleteness results in arithmetic from combining addition and successor with multiplication [Smith,P]
Multiplication only generates incompleteness if combined with addition and successor [Smith,P]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / e. Caesar problem
Some suggest that the Julius Caesar problem involves category mistakes [Magidor]
8. Modes of Existence / A. Relations / 4. Formal Relations / c. Ancestral relation
The 'ancestral' of a relation is a new relation which creates a long chain of the original relation [Smith,P]
9. Objects / B. Unity of Objects / 3. Unity Problems / c. Statue and clay
We can explain the statue/clay problem by a category mistake with a false premise [Magidor]
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / a. Conceivable as possible
Modal Rationalism: conceivability gives a priori access to modal truths [Chalmers, by Stalnaker]
Evaluate primary possibility from some world, and secondary possibility from this world [Chalmers, by Vaidya]
18. Thought / A. Modes of Thought / 2. Propositional Attitudes
Propositional attitudes relate agents to either propositions, or meanings, or sentence/utterances [Magidor]
18. Thought / C. Content / 1. Content
Two sentences with different meanings can, on occasion, have the same content [Magidor]
18. Thought / D. Concepts / 4. Structure of Concepts / b. Analysis of concepts
To grasp 'two' and 'green', must you know that two is not green? [Magidor]
19. Language / C. Assigning Meanings / 1. Syntax
Generative semantics says structure is determined by semantics as well as syntactic rules [Magidor]
'John is easy to please' and 'John is eager to please' have different deep structure [Magidor]
19. Language / C. Assigning Meanings / 2. Semantics
The semantics of a sentence is its potential for changing a context [Magidor]
19. Language / C. Assigning Meanings / 4. Compositionality
Strong compositionality says meaningful expressions syntactically well-formed are meaningful [Magidor]
Weaker compositionality says meaningful well-formed sentences get the meaning from the parts [Magidor]
Understanding unlimited numbers of sentences suggests that meaning is compositional [Magidor]
19. Language / D. Propositions / 2. Abstract Propositions / b. Propositions as possible worlds
Are there partial propositions, lacking truth value in some possible worlds? [Magidor]
19. Language / F. Communication / 5. Pragmatics / a. Contextual meaning
A sentence can be meaningful, and yet lack a truth value [Magidor]
In the pragmatic approach, presuppositions are assumed in a context, for successful assertion [Magidor]
19. Language / F. Communication / 5. Pragmatics / b. Implicature
The infelicitiousness of trivial truth is explained by uninformativeness, or a static context-set [Magidor]
The infelicitiousness of trivial falsity is explained by expectations, or the loss of a context-set [Magidor]
19. Language / F. Communication / 5. Pragmatics / c. Presupposition
A presupposition is what makes an utterance sound wrong if it is not assumed? [Magidor]
A test for presupposition would be if it provoked 'hey wait a minute - I have no idea that....' [Magidor]
The best tests for presupposition are projecting it to negation, conditional, conjunction, questions [Magidor]
If both s and not-s entail a sentence p, then p is a presupposition [Magidor]
Why do certain words trigger presuppositions? [Magidor]
19. Language / F. Communication / 6. Interpreting Language / d. Metaphor
Gricean theories of metaphor involve conversational implicatures based on literal meanings [Magidor]
Non-cognitivist views of metaphor says there are no metaphorical meanings, just effects of the literal [Magidor]
Metaphors tend to involve category mistakes, by joining disjoint domains [Magidor]
One theory says metaphors mean the same as the corresponding simile [Magidor]
Theories of metaphor divide over whether they must have literal meanings [Magidor]
The simile view of metaphors removes their magic, and won't explain why we use them [Magidor]
Maybe a metaphor is just a substitute for what is intended literally, like 'icy' for 'unemotional' [Magidor]
Metaphors as substitutes for the literal misses one predicate varying with context [Magidor]