Combining Philosophers

All the ideas for Laurence Bonjour, Volker Halbach and Oxford Univ 1350

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99 ideas

1. Philosophy / B. History of Ideas / 4. Early European Thought
There is a five shilling fine for each point of divergence from the thinking of Aristotle [Oxford Univ 1350]
1. Philosophy / D. Nature of Philosophy / 1. Philosophy
Philosophy is a priori if it is anything [Bonjour]
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 / A. Nature of Reason / 3. Pure Reason
Perceiving necessary connections is the essence of reasoning [Bonjour]
2. Reason / A. Nature of Reason / 6. Coherence
Coherence can't be validated by appeal to coherence [Bonjour]
For any given area, there seem to be a huge number of possible coherent systems of beliefs [Bonjour]
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]
Truth definitions don't produce a good theory, because they go beyond your current language [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
In semantic theories of truth, the predicate is in an object-language, and the definition in a metalanguage [Halbach]
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
Instead of a truth definition, add a primitive truth predicate, and axioms for how it works [Halbach]
Should axiomatic truth be 'conservative' - not proving anything apart from implications of the axioms? [Halbach]
If truth is defined it can be eliminated, whereas axiomatic truth has various commitments [Halbach]
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]
Axiomatic theories of truth need a weak logical framework, and not a strong metatheory [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
The KF theory is useful, but it is not a theory containing its own truth predicate [Halbach]
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]
3. Truth / H. Deflationary Truth / 2. Deflationary Truth
Deflationists say truth merely serves to express infinite conjunctions [Halbach]
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
To prove the consistency of set theory, we must go beyond set theory [Halbach]
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 / C. Ontology of Logic / 1. Ontology of Logic
We can use truth instead of ontologically loaded second-order comprehension assumptions about properties [Halbach]
5. Theory of Logic / E. Structures of Logic / 7. Predicates in Logic
Instead of saying x has a property, we can say a formula is true of x - as long as we have 'true' [Halbach]
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 / K. Features of Logics / 3. Soundness
Soundness must involve truth; the soundness of PA certainly needs it [Halbach]
You cannot just say all of Peano arithmetic is true, as 'true' isn't part of the system [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 / 4. Paradoxes in Logic / e. The Lottery paradox
The Lottery Paradox says each ticket is likely to lose, so there probably won't be a winner [Bonjour, by PG]
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 / 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 / 6. Logicism / b. Type theory
Set theory was liberated early from types, and recent truth-theories are exploring type-free [Halbach]
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]
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 / 1. Possibility
The concept of possibility is prior to that of necessity [Bonjour]
11. Knowledge Aims / A. Knowledge / 1. Knowledge
The concept of knowledge is so confused that it is best avoided [Bonjour]
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
It is hard to give the concept of 'self-evident' a clear and defensible characterization [Bonjour]
12. Knowledge Sources / B. Perception / 8. Adverbial Theory
The adverbial account will still be needed when a mind apprehends its sense-data [Bonjour]
12. Knowledge Sources / C. Rationalism / 1. Rationalism
Moderate rationalists believe in fallible a priori justification [Bonjour]
Our rules of thought can only be judged by pure rational insight [Bonjour]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / a. Foundationalism
Externalist theories of knowledge are one species of foundationalism [Bonjour]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / b. Basic beliefs
The big problem for foundationalism is to explain how basic beliefs are possible [Bonjour]
Conscious states have built-in awareness of content, so we know if a conceptual description of it is correct [Bonjour]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / d. Rational foundations
A priori justification requires understanding but no experience [Bonjour]
You can't explain away a priori justification as analyticity, and you can't totally give it up [Bonjour]
A priori justification can vary in degree [Bonjour]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / e. Pro-foundations
The main argument for foundationalism is that all other theories involve a regress leading to scepticism [Bonjour]
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / f. Foundationalism critique
The induction problem blocks any attempted proof of physical statements [Bonjour]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
A coherence theory of justification can combine with a correspondence theory of truth [Bonjour]
There will always be a vast number of equally coherent but rival systems [Bonjour]
Empirical coherence must attribute reliability to spontaneous experience [Bonjour]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / b. Pro-coherentism
The objection that a negated system is equally coherent assume that coherence is consistency [Bonjour]
A well written novel cannot possibly match a real belief system for coherence [Bonjour]
A coherent system can be justified with initial beliefs lacking all credibility [Bonjour]
The best explanation of coherent observations is they are caused by and correspond to reality [Bonjour]
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / c. Coherentism critique
My incoherent beliefs about art should not undermine my very coherent beliefs about physics [Bonjour]
Coherence seems to justify empirical beliefs about externals when there is no external input [Bonjour]
Coherentists must give a reason why coherent justification is likely to lead to the truth [Bonjour]
13. Knowledge Criteria / C. External Justification / 1. External Justification
Extreme externalism says no more justification is required than the truth of the belief [Bonjour]
Externalist theories of justification don't require believers to have reasons for their beliefs [Bonjour]
13. Knowledge Criteria / C. External Justification / 3. Reliabilism / a. Reliable knowledge
Reliabilists disagree over whether some further requirement is needed to produce knowledge [Bonjour]
13. Knowledge Criteria / C. External Justification / 3. Reliabilism / b. Anti-reliabilism
External reliability is not enough, if the internal state of the believer is known to be irrational [Bonjour]
If the reliable facts producing a belief are unknown to me, my belief is not rational or responsible [Bonjour]
13. Knowledge Criteria / C. External Justification / 10. Anti External Justification
Even if there is no obvious irrationality, it may be irrational to base knowledge entirely on external criteria [Bonjour]
Externalism means we have no reason to believe, which is strong scepticism [Bonjour]
14. Science / A. Basis of Science / 5. Anomalies
Anomalies challenge the claim that the basic explanations are actually basic [Bonjour]
14. Science / C. Induction / 2. Aims of Induction
Induction must go beyond the evidence, in order to explain why the evidence occurred [Bonjour]
15. Nature of Minds / B. Features of Minds / 1. Consciousness / f. Higher-order thought
If neither the first-level nor the second-level is itself conscious, there seems to be no consciousness present [Bonjour]
18. Thought / C. Content / 1. Content
All thought represents either properties or indexicals [Bonjour]
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 / 6. Interpreting Language / b. Indeterminate translation
Indeterminacy of translation is actually indeterminacy of meaning and belief [Bonjour]