Ideas of Bob Hale, by Theme

[British, fl. 2001, Professor at Glasgow Univerity.]

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1. Philosophy / E. Nature of Metaphysics / 1. Nature of Metaphysics
You cannot understand what exists without understanding possibility and necessity
1. Philosophy / F. Analytic Philosophy / 4. Ordinary Language
Questions about objects are questions about certain non-vacuous singular terms
2. Reason / D. Definition / 6. Definition by Essence
A canonical defintion specifies the type of thing, and what distinguish this specimen
4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
The two Barcan principles are easily proved in fairly basic modal logic
With a negative free logic, we can dispense with the Barcan formulae
5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic
If second-order variables range over sets, those are just objects; properties and relations aren't sets
5. Theory of Logic / C. Ontology of Logic / 4. Logic by Convention
Maybe conventionalism applies to meaning, but not to the truth of propositions expressed
5. Theory of Logic / F. Referring in Logic / 1. Naming / d. Singular terms
We should decide whether singular terms are genuine by their usage
If singular terms can't be language-neutral, then we face a relativity about their objects
Often the same singular term does not ensure reliable inference
Plenty of clear examples have singular terms with no ontological commitment
An expression is a genuine singular term if it resists elimination by paraphrase
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
Unlike axiom proofs, natural deduction proofs needn't focus on logical truths and theorems
6. Mathematics / A. Nature of Mathematics / 3. Numbers / g. Real numbers
The real numbers may be introduced by abstraction as ratios of quantities
6. Mathematics / C. Sources of Mathematics / 6. Logicism / c. Neo-logicism
Add Hume's principle to logic, to get numbers; arithmetic truths rest on the nature of the numbers
7. Existence / C. Structure of Existence / 5. Supervenience / a. Nature of supervenience
Interesting supervenience must characterise the base quite differently from what supervenes on it
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / a. Abstract/concrete
The abstract/concrete distinction is based on what is perceivable, causal and located
Colours and points seem to be both concrete and abstract
Token-letters and token-words are concrete objects, type-letters and type-words abstract
The abstract/concrete distinction is in the relations in the identity-criteria of object-names
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / b. Levels of abstraction
There is a hierarchy of abstraction, based on steps taken by equivalence relations
7. Existence / D. Theories of Reality / 7. Facts / c. Facts and truths
There is no gap between a fact that p, and it is true that p; so we only have the truth-condtions for p
8. Modes of Existence / D. Universals / 1. Universals
Realists take universals to be the referrents of both adjectives and of nouns
It is doubtful if one entity, a universal, can be picked out by both predicates and abstract nouns
If F can't have location, there is no problem of things having F in different locations
8. Modes of Existence / E. Nominalism / 1. Nominalism / c. Nominalism about abstracta
Objections to Frege: abstracta are unknowable, non-independent, unstatable, unindividuated
9. Objects / A. Existence of Objects / 2. Abstract Objects / a. Nature of abstracta
Shapes and directions are of something, but games and musical compositions are not
Many abstract objects, such as chess, seem non-spatial, but are not atemporal
If the mental is non-spatial but temporal, then it must be classified as abstract
Being abstract is based on a relation between things which are spatially separated
9. Objects / A. Existence of Objects / 2. Abstract Objects / c. Modern abstracta
The modern Fregean use of the term 'object' is much broader than the ordinary usage
9. Objects / A. Existence of Objects / 2. Abstract Objects / d. Problems with abstracta
We can't believe in a 'whereabouts' because we ask 'what kind of object is it?'
9. Objects / C. Structure of Objects / 5. Composition of an Object
If a chair could be made of slightly different material, that could lead to big changes
9. Objects / F. Identity among Objects / 1. Concept of Identity
The relations featured in criteria of identity are always equivalence relations
9. Objects / F. Identity among Objects / 3. Relative Identity
We sometimes apply identity without having a real criterion
10. Modality / A. Necessity / 2. Nature of Necessity
Absolute necessity might be achievable either logically or metaphysically
10. Modality / A. Necessity / 3. Types of Necessity
Absolute necessities are necessarily necessary
Maybe not-p is logically possible, but p is metaphysically necessary, so the latter is not absolute
'Relative' necessity is just a logical consequence of some statements ('strong' if they are all true)
A strong necessity entails a weaker one, but not conversely; possibilities go the other way
'Absolute necessity' is when there is no restriction on the things which necessitate p
Logical and metaphysical necessities differ in their vocabulary, and their underlying entities
10. Modality / A. Necessity / 5. Metaphysical Necessity
Metaphysical necessity says there is no possibility of falsehood
10. Modality / A. Necessity / 6. Logical Necessity
Logical necessities are true in virtue of the nature of all logical concepts
'Broadly' logical necessities are derived (in a structure) entirely from the concepts
In the McFetridge view, logical necessity means a consequent must be true if the antecedent is
Logical necessity is something which is true, no matter what else is the case
Maybe each type of logic has its own necessity, gradually becoming broader
10. Modality / C. Sources of Modality / 1. Sources of Necessity
Explanation of necessity must rest on something necessary or something contingent
Why is this necessary, and what is necessity in general; why is this necessary truth true, and why necessary?
The explanation of a necessity can be by a truth (which may only happen to be a necessary truth)
It seems that we cannot show that modal facts depend on non-modal facts
10. Modality / C. Sources of Modality / 3. Necessity by Convention
If necessity rests on linguistic conventions, those are contingent, so there is no necessity
10. Modality / C. Sources of Modality / 4. Necessity from Concepts
Concept-identities explain how we know necessities, not why they are necessary
Conceptual necessities are made true by all concepts
10. Modality / C. Sources of Modality / 6. Necessity from Essence
The big challenge for essentialist views of modality is things having necessary existence
Essentialism doesn't explain necessity reductively; it explains all necessities in terms of a few basic natures
If necessity derives from essences, how do we explain the necessary existence of essences?
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
What are these worlds, that being true in all of them makes something necessary?
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
Possible worlds make every proposition true or false, which endorses classical logic
18. Thought / C. Content / 6. Broad Content
The molecules may explain the water, but they are not what 'water' means