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All the ideas for 'On What Grounds What', 'Axiomatic Theories of Truth' and 'Ontology and the Ambitions of Metaphysics'

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89 ideas

1. Philosophy / E. Nature of Metaphysics / 1. Nature of Metaphysics
Metaphysics is (supposedly) first the ontology, then in general what things are like [Hofweber]
Modern Quinean metaphysics is about what exists, but Aristotelian metaphysics asks about grounding [Schaffer,J]
1. Philosophy / E. Nature of Metaphysics / 3. Metaphysical Systems
If you tore the metaphysics out of philosophy, the whole enterprise would collapse [Schaffer,J]
1. Philosophy / E. Nature of Metaphysics / 7. Against Metaphysics
'Fundamentality' is either a superficial idea, or much too obscure [Hofweber]
1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
Analysis rests on natural language, but its ideal is a framework which revises language [Halbach]
2. Reason / B. Laws of Thought / 6. Ockham's Razor
We should not multiply basic entities, but we can have as many derivative entities as we like [Schaffer,J]
2. Reason / D. Definition / 2. Aims of Definition
An explicit definition enables the elimination of what is defined [Halbach]
2. Reason / E. Argument / 3. Analogy
Don't trust analogies; they are no more than a guideline [Halbach]
3. Truth / A. Truth Problems / 1. Truth
Truth axioms prove objects exist, so truth doesn't seem to be a logical notion [Halbach]
Truth-value 'gluts' allow two truth values together; 'gaps' give a partial conception of truth [Halbach]
3. Truth / A. Truth Problems / 2. Defining Truth
Any definition of truth requires a metalanguage [Halbach]
Traditional definitions of truth often make it more obscure, rather than less [Halbach]
If people have big doubts about truth, a definition might give it more credibility [Halbach]
3. Truth / F. Semantic Truth / 1. Tarski's Truth / c. Meta-language for truth
Semantic theories avoid Tarski's Theorem by sticking to a sublanguage [Halbach]
3. Truth / F. Semantic Truth / 2. Semantic Truth
Disquotational truth theories are short of deductive power [Halbach]
3. Truth / G. Axiomatic Truth / 1. Axiomatic Truth
Axiomatic truth doesn't presuppose a truth-definition, though it could admit it at a later stage [Halbach]
To axiomatise Tarski's truth definition, we need a binary predicate for his 'satisfaction' [Halbach]
Compositional Truth CT has the truth of a sentence depending of the semantic values of its constituents [Halbach]
The main semantic theories of truth are Kripke's theory, and revisions semantics [Halbach]
Gödel numbering means a theory of truth can use Peano Arithmetic as its base theory [Halbach]
Truth axioms need a base theory, because that is where truth issues arise [Halbach]
CT proves PA consistent, which PA can't do on its own, so CT is not conservative over PA [Halbach]
We know a complete axiomatisation of truth is not feasible [Halbach]
A theory is 'conservative' if it adds no new theorems to its base theory [Halbach, by PG]
The Tarski Biconditional theory TB is Peano Arithmetic, plus truth, plus all Tarski bi-conditionals [Halbach]
Theories of truth are 'typed' (truth can't apply to sentences containing 'true'), or 'type-free' [Halbach]
3. Truth / G. Axiomatic Truth / 2. FS Truth Axioms
Friedman-Sheard is type-free Compositional Truth, with two inference rules for truth [Halbach]
3. Truth / G. Axiomatic Truth / 3. KF Truth Axioms
Kripke-Feferman theory KF axiomatises Kripke fixed-points, with Strong Kleene logic with gluts [Halbach]
The KF is much stronger deductively than FS, which relies on classical truth [Halbach]
The KF theory is useful, but it is not a theory containing its own truth predicate [Halbach]
3. Truth / H. Deflationary Truth / 1. Redundant Truth
'It's true that Fido is a dog' conjures up a contrast class, of 'it's false' or 'it's unlikely' [Hofweber]
3. Truth / H. Deflationary Truth / 2. Deflationary Truth
Deflationism says truth is a disquotation device to express generalisations, adding no new knowledge [Halbach]
The main problem for deflationists is they can express generalisations, but not prove them [Halbach]
Deflationists say truth is just for expressing infinite conjunctions or generalisations [Halbach]
Compositional Truth CT proves generalisations, so is preferred in discussions of deflationism [Halbach]
Some say deflationism is axioms which are conservative over the base theory [Halbach]
4. Formal Logic / E. Nonclassical Logics / 3. Many-Valued Logic
In Strong Kleene logic a disjunction just needs one disjunct to be true [Halbach]
In Weak Kleene logic there are 'gaps', neither true nor false if one component lacks a truth value [Halbach]
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Every attempt at formal rigour uses some set theory [Halbach]
5. Theory of Logic / A. Overview of Logic / 6. Classical Logic
The underestimated costs of giving up classical logic are found in mathematical reasoning [Halbach]
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
Since properties can have properties, some theorists rank them in 'types' [Hofweber]
5. Theory of Logic / E. Structures of Logic / 8. Theories in Logic
A theory is some formulae and all of their consequences [Halbach]
5. Theory of Logic / F. Referring in Logic / 1. Naming / c. Names as referential
Maybe not even names are referential, but are just by used by speakers to refer [Hofweber]
5. Theory of Logic / F. Referring in Logic / 1. Naming / d. Singular terms
'Singular terms' are not found in modern linguistics, and are not the same as noun phrases [Hofweber]
If two processes are said to be identical, that doesn't make their terms refer to entities [Hofweber]
5. Theory of Logic / G. Quantification / 1. Quantification
The inferential quantifier focuses on truth; the domain quantifier focuses on reality [Hofweber]
5. Theory of Logic / K. Features of Logics / 3. Soundness
You cannot just say all of Peano arithmetic is true, as 'true' isn't part of the system [Halbach]
Soundness must involve truth; the soundness of PA certainly needs it [Halbach]
Normally we only endorse a theory if we believe it to be sound [Halbach]
5. Theory of Logic / L. Paradox / 1. Paradox
Many new paradoxes may await us when we study interactions between frameworks [Halbach]
5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox
The liar paradox applies truth to a negated truth (but the conditional will serve equally) [Halbach]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / a. Numbers
Numbers are used as singular terms, as adjectives, and as symbols [Hofweber]
The Amazonian Piraha language is said to have no number words [Hofweber]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / f. Arithmetic
The fundamental theorem of arithmetic is that all numbers are composed uniquely of primes [Hofweber]
6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / g. Applying mathematics
How can words be used for counting if they are objects? [Hofweber]
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / d. Peano arithmetic
The compactness theorem can prove nonstandard models of PA [Halbach]
The global reflection principle seems to express the soundness of Peano Arithmetic [Halbach]
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
To reduce PA to ZF, we represent the non-negative integers with von Neumann ordinals [Halbach]
6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / a. For mathematical platonism
If 'there are red roses' implies 'there are roses', then 'there are prime numbers' implies 'there are numbers' [Schaffer,J]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
Logicism makes sense of our ability to know arithmetic just by thought [Hofweber]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / b. Type theory
Set theory was liberated early from types, and recent truth-theories are exploring type-free [Halbach]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / c. Neo-logicism
Neo-Fregeans are dazzled by a technical result, and ignore practicalities [Hofweber]
7. Existence / C. Structure of Existence / 1. Grounding / a. Nature of grounding
Grounding is unanalysable and primitive, and is the basic structuring concept in metaphysics [Schaffer,J]
7. Existence / C. Structure of Existence / 2. Reduction
That Peano arithmetic is interpretable in ZF set theory is taken by philosophers as a reduction [Halbach]
7. Existence / C. Structure of Existence / 5. Supervenience / a. Nature of supervenience
Supervenience is just modal correlation [Schaffer,J]
7. Existence / C. Structure of Existence / 5. Supervenience / c. Significance of supervenience
Supervenience offers little explanation for things which necessarily go together [Hofweber]
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / a. Abstract/concrete
The cosmos is the only fundamental entity, from which all else exists by abstraction [Schaffer,J]
7. Existence / D. Theories of Reality / 3. Reality
Reality can be seen as the totality of facts, or as the totality of things [Hofweber]
7. Existence / D. Theories of Reality / 8. Facts / a. Facts
There are probably ineffable facts, systematically hidden from us [Hofweber]
7. Existence / E. Categories / 4. Category Realism
Maybe categories are just the different ways that things depend on basic substances [Schaffer,J]
9. Objects / A. Existence of Objects / 6. Nihilism about Objects
Our perceptual beliefs are about ordinary objects, not about simples arranged chair-wise [Hofweber]
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
There exist heaps with no integral unity, so we should accept arbitrary composites in the same way [Schaffer,J]
The notion of 'grounding' can explain integrated wholes in a way that mere aggregates can't [Schaffer,J]
10. Modality / A. Necessity / 2. Nature of Necessity
Maybe necessity is a predicate, not the usual operator, to make it more like truth [Halbach]
10. Modality / B. Possibility / 9. Counterfactuals
Counterfactuals are essential for planning, and learning from mistakes [Hofweber]
10. Modality / E. Possible worlds / 1. Possible Worlds / b. Impossible worlds
Belief in impossible worlds may require dialetheism [Schaffer,J]
11. Knowledge Aims / B. Certain Knowledge / 2. Common Sense Certainty
'Moorean certainties' are more credible than any sceptical argument [Schaffer,J]
19. Language / A. Nature of Meaning / 1. Meaning
The "Fido"-Fido theory of meaning says every expression in a language has a referent [Hofweber]
19. Language / A. Nature of Meaning / 7. Meaning Holism / c. Meaning by Role
Inferential role semantics is an alternative to semantics that connects to the world [Hofweber]
19. Language / C. Assigning Meanings / 1. Syntax
Syntactic form concerns the focus of the sentence, as well as the truth-conditions [Hofweber]
19. Language / C. Assigning Meanings / 3. Predicates
Properties can be expressed in a language despite the absence of a single word for them [Hofweber]
'Being taller than this' is a predicate which can express many different properties [Hofweber]
19. Language / C. Assigning Meanings / 4. Compositionality
Compositonality is a way to build up the truth-conditions of a sentence [Hofweber]
19. Language / D. Propositions / 1. Propositions
Proposition have no content, because they are content [Hofweber]
19. Language / D. Propositions / 2. Abstract Propositions / a. Propositions as sense
Without propositions there can be no beliefs or desires [Hofweber]
19. Language / D. Propositions / 3. Concrete Propositions
Do there exist thoughts which we are incapable of thinking? [Hofweber]
19. Language / D. Propositions / 4. Mental Propositions
We need propositions to ascribe the same beliefs to people with different languages [Halbach]
19. Language / F. Communication / 5. Pragmatics / a. Contextual meaning
'Semantic type coercion' is selecting the reading of a word to make the best sense [Hofweber]
19. Language / F. Communication / 5. Pragmatics / b. Implicature
'Background deletion' is appropriately omitting background from an answer [Hofweber]