Combining Philosophers

All the ideas for Volker Halbach, William of Ockham and Daniel Jacobson

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101 ideas

1. Philosophy / D. Nature of Philosophy / 8. Humour
Jokes can sometimes be funny because they are offensive [Jacobson,D]
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 / 3. Non-Contradiction
From an impossibility anything follows [William of Ockham]
2. Reason / B. Laws of Thought / 6. Ockham's Razor
Why use more things when fewer will do? [William of Ockham]
Do not multiply entities beyond necessity [William of Ockham]
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-value 'gluts' allow two truth values together; 'gaps' give a partial conception of truth [Halbach]
Truth axioms prove objects exist, so truth doesn't seem to be a logical notion [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 / C. Correspondence Truth / 1. Correspondence Truth
A proposition is true if its subject and predicate stand for the same thing [William of Ockham]
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
Axiomatic theories of truth need a weak logical framework, and not a strong metatheory [Halbach]
CT proves PA consistent, which PA can't do on its own, so CT is not conservative over PA [Halbach]
Should axiomatic truth be 'conservative' - not proving anything apart from implications of the axioms? [Halbach]
Ockham had an early axiomatic account of truth [William of Ockham, by Halbach]
Instead of a truth definition, add a primitive truth predicate, and axioms for how it works [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]
The main semantic theories of truth are Kripke's theory, and revisions semantics [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]
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]
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 / 2. Deflationary Truth
Some say deflationism is axioms which are conservative over the base theory [Halbach]
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]
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 / G. Quantification / 1. Quantification
The word 'every' only signifies when added to a term such as 'man', referring to all men [William of Ockham]
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]
Normally we only endorse a theory if we believe it to be sound [Halbach]
Soundness must involve truth; the soundness of PA certainly needs it [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 / 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 / 5. Numbers as Adjectival
Just as unity is not a property of a single thing, so numbers are not properties of many things [William of Ockham]
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 / A. Nature of Existence / 3. Being / g. Particular being
The words 'thing' and 'to be' assert the same idea, as a noun and as a verb [William of Ockham]
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 / E. Categories / 5. Category Anti-Realism
Ockham was an anti-realist about the categories [William of Ockham, by Pasnau]
Our words and concepts don't always correspond to what is out there [William of Ockham]
8. Modes of Existence / A. Relations / 1. Nature of Relations
Relations are expressed either as absolute facts, or by a relational concept [William of Ockham]
8. Modes of Existence / D. Universals / 5. Universals as Concepts
Species and genera are individual concepts which naturally signify many individuals [William of Ockham]
8. Modes of Existence / E. Nominalism / 1. Nominalism / b. Nominalism about universals
A universal is not a real feature of objects, but only a thought-object in the mind [William of Ockham]
Universals are single things, and only universal in what they signify [William of Ockham]
9. Objects / B. Unity of Objects / 2. Substance / c. Types of substance
Cut wood doesn't make a new substance, but seems to make separate subjects [William of Ockham]
9. Objects / C. Structure of Objects / 2. Hylomorphism / a. Hylomorphism
Hot water naturally cools down, which is due to the substantial form of the water [William of Ockham]
9. Objects / C. Structure of Objects / 4. Quantity of an Object
Ockham says matter must be extended, so we don't need Quantity [William of Ockham, by Pasnau]
Matter gets its quantity from condensation and rarefaction, which is just local motion [William of Ockham]
9. Objects / D. Essence of Objects / 6. Essence as Unifier
If essence and existence were two things, one could exist without the other, which is impossible [William of Ockham]
9. Objects / D. Essence of Objects / 12. Essential Parts
If parts change, the whole changes [William of Ockham]
10. Modality / A. Necessity / 2. Nature of Necessity
Maybe necessity is a predicate, not the usual operator, to make it more like truth [Halbach]
11. Knowledge Aims / A. Knowledge / 1. Knowledge
Knowledge is a quality existing subjectively in the soul [William of Ockham]
Sometimes 'knowledge' just concerns the conclusion, sometimes the whole demonstration [William of Ockham]
11. Knowledge Aims / A. Knowledge / 4. Belief / c. Aim of beliefs
Our intellect only assents to what we believe to be true [William of Ockham]
11. Knowledge Aims / B. Certain Knowledge / 1. Certainty
Knowledge is certain cognition of something that is true [William of Ockham]
15. Nature of Minds / C. Capacities of Minds / 3. Abstraction by mind
Abstractive cognition knows universals abstracted from many singulars [William of Ockham]
If an animal approached from a distance, we might abstract 'animal' from one instance [William of Ockham]
17. Mind and Body / D. Property Dualism / 6. Mysterianism
There are no secure foundations to prove the separate existence of mind, in reason or experience [William of Ockham]
18. Thought / E. Abstraction / 2. Abstracta by Selection
A universal is the result of abstraction, which is only a kind of mental picturing [William of Ockham]
19. Language / D. Propositions / 4. Mental Propositions
Some concepts for propositions exist only in the mind, and in no language [William of Ockham]
We need propositions to ascribe the same beliefs to people with different languages [Halbach]
21. Aesthetics / A. Aesthetic Experience / 2. Aesthetic Attitude
We don't often respond to events in art as if they were real events [Jacobson,D]
21. Aesthetics / C. Artistic Issues / 7. Art and Morality
Audiences can be too moral [Jacobson,D]
'Autonomism' says the morality is irrelevant to the aesthetics [Jacobson,D]
Moral defects of art can be among its aesthetic virtues [Jacobson,D]
Immoral art encourages immoral emotions [Jacobson,D]
Moderate moralism says moral qualities can sometimes also be aesthetic qualities [Jacobson,D]
We can judge art ethically, or rate its ethical influence, or assess its quality via its ethics [Jacobson,D]
26. Natural Theory / A. Speculations on Nature / 7. Later Matter Theories / b. Corpuscles
Every extended material substance is composed of parts distant from one another [William of Ockham]
27. Natural Reality / D. Time / 1. Nature of Time / i. Denying time
The past has ceased to exist, and the future does not yet exist, so time does not exist [William of Ockham]
28. God / A. Divine Nature / 3. Divine Perfections
God is not wise, but more-than-wise; God is not good, but more-than-good [William of Ockham]
28. God / A. Divine Nature / 6. Divine Morality / d. God decrees morality
William of Ockham is the main spokesman for God's commands being the source of morality [William of Ockham]
28. God / C. Attitudes to God / 4. God Reflects Humanity
We could never form a concept of God's wisdom if we couldn't abstract it from creatures [William of Ockham]
29. Religion / B. Monotheistic Religion / 4. Christianity / a. Christianity
To love God means to love whatever God wills to be loved [William of Ockham]
29. Religion / B. Monotheistic Religion / 4. Christianity / c. Angels
Even an angel must have some location [William of Ockham, by Pasnau]