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All the ideas for 'Exigency to Exist in Essences', 'Tarski's Theory of Truth' and 'The Identity of Indiscernibles'

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16 ideas

3. Truth / A. Truth Problems / 4. Uses of Truth
The notion of truth is to help us make use of the utterances of others [Field,H]
     Full Idea: I suspect that the original purpose of the notion of truth was to aid us in utilizing the utterances of others in drawing conclusions about the world,...so we must attend to its social role, and that being in a position to assert something is what counts.
     From: Hartry Field (Tarski's Theory of Truth [1972], §5)
     A reaction: [Last bit compressed] This sounds excellent. Deflationary and redundancy views are based on a highly individualistic view of utterances and truth, but we need to be much more contextual and pragmatic if we are to get the right story.
3. Truth / A. Truth Problems / 9. Rejecting Truth
In the early 1930s many philosophers thought truth was not scientific [Field,H]
     Full Idea: In the early 1930s many philosophers believed that the notion of truth could not be incorporated into a scientific conception of the world.
     From: Hartry Field (Tarski's Theory of Truth [1972], §3)
     A reaction: This leads on to an account of why Tarski's formal version was so important, and Field emphasises Tarski's physicalist metaphysic.
3. Truth / F. Semantic Truth / 1. Tarski's Truth / a. Tarski's truth definition
Tarski reduced truth to reference or denotation [Field,H, by Hart,WD]
     Full Idea: Tarski can be viewed as having reduced truth to reference or denotation.
     From: report of Hartry Field (Tarski's Theory of Truth [1972]) by William D. Hart - The Evolution of Logic 4
Tarski really explained truth in terms of denoting, predicating and satisfied functions [Field,H]
     Full Idea: A proper account of Tarski's truth definition explains truth in terms of three other semantic notions: what it is for a name to denote something, and for a predicate to apply to something, and for a function symbol to be fulfilled by a pair of things.
     From: Hartry Field (Tarski's Theory of Truth [1972])
     A reaction: This is Field's 'T1' version, which is meant to spell out what was really going on in Tarski's account.
3. Truth / F. Semantic Truth / 1. Tarski's Truth / b. Satisfaction and truth
Tarski just reduced truth to some other undefined semantic notions [Field,H]
     Full Idea: It is normally claimed that Tarski defined truth using no undefined semantic terms, but I argue that he reduced the notion of truth to certain other semantic notions, but did not in any way explicate these other notions.
     From: Hartry Field (Tarski's Theory of Truth [1972], §0)
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / j. Axiom of Choice IX
The Axiom of Choice needs a criterion of choice [Black]
     Full Idea: Some mathematicians seem to think that talk of an Axiom of Choice allows them to choose a single member of a collection when there is no criterion of choice.
     From: Max Black (The Identity of Indiscernibles [1952], p.68)
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
Tarski gives us the account of truth needed to build a group of true sentences in a model [Field,H]
     Full Idea: Model theory must choose the denotations of the primitives so that all of a group of sentences come out true, so we need a theory of how the truth value of a sentence depends on the denotation of its primitive nonlogical parts, which Tarski gives us.
     From: Hartry Field (Tarski's Theory of Truth [1972], §1)
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Model theory is unusual in restricting the range of the quantifiers [Field,H]
     Full Idea: In model theory we are interested in allowing a slightly unusual semantics for quantifiers: we are willing to allow that the quantifier not range over everything.
     From: Hartry Field (Tarski's Theory of Truth [1972], n 5)
7. Existence / A. Nature of Existence / 5. Reason for Existence
Possibles demand existence, so as many of them as possible must actually exist [Leibniz]
     Full Idea: From the conflict of all the possibles demanding existence, this at once follows, that there exists that series of things by which as many of them as possible exist.
     From: Gottfried Leibniz (Exigency to Exist in Essences [1690], p.91)
     A reaction: I'm in tune with a lot of Leibniz, but my head swims with this one. He seems to be a Lewisian about possible worlds - that they are concrete existing entities (with appetites!). Could Lewis include Leibniz's idea in his system?
God's sufficient reason for choosing reality is in the fitness or perfection of possibilities [Leibniz]
     Full Idea: The sufficient reason for God's choice can be found only in the fitness (convenance) or in the degree of perfection that the several worlds possess.
     From: Gottfried Leibniz (Exigency to Exist in Essences [1690], p.92)
     A reaction: The 'fitness' of a world and its 'perfection' seem very different things. A piece of a jigsaw can have wonderful fitness, without perfection. Occasionally you get that sinking feeling with metaphysicians that they just make it up.
9. Objects / A. Existence of Objects / 5. Individuation / b. Individuation by properties
Two things can only be distinguished by a distinct property or a distinct relation [Black]
     Full Idea: The only way we can discover that two things exist is by finding out that one has a quality not possessed by the other, or else that one has a relational characteristic that the other hasn't.
     From: Max Black (The Identity of Indiscernibles [1952], p.67)
     A reaction: At least this doesn't conflate relations with properties. Note that this idea is clearly epistemological, and in no way rules out the separateness of two objects which none of us can ever discern. Maybe the Earth has two Suns, which imperceptibly swap.
9. Objects / F. Identity among Objects / 5. Self-Identity
The 'property' of self-identity is uselessly tautological [Black]
     Full Idea: Saying that 'a has the property of being identical with a' is a roundabout way of saying nothing - a useless tautology - and means not more than 'a is a'
     From: Max Black (The Identity of Indiscernibles [1952], p.66)
     A reaction: This matter resembles the problem of the number zero, and the empty set, which seem to be crucial entities for logicians, but of no interest to a common sense view of the world. So much the worse for logic, I am inclined to say.
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
If the universe just held two indiscernibles spheres, that refutes the Identity of Indiscernibles [Black]
     Full Idea: Isn't it logically possible that the universe should have contained nothing but two exactly similar spheres? ...So two things would have all their properties in common, and this would refute the Principle of the Identity of Indiscernibles.
     From: Max Black (The Identity of Indiscernibles [1952], p.67)
     A reaction: [Black is the originator of this famous example] It also appears to be naturally possible. An observer at an instant of viewing will discern a relational difference relative to themselves. Most people take Black's objection to be decisive.
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
The actual universe is the richest composite of what is possible [Leibniz]
     Full Idea: The actual universe is the collection of the possibles which forms the richest composite.
     From: Gottfried Leibniz (Exigency to Exist in Essences [1690], p.92)
     A reaction: 'Richest' for Leibniz means a maximum combination of existence, order and variety. It's rather like picking the best starting team from a squad of footballers.
17. Mind and Body / E. Mind as Physical / 2. Reduction of Mind
'Valence' and 'gene' had to be reduced to show their compatibility with physicalism [Field,H]
     Full Idea: 'Valence' and 'gene' were perfectly clear long before anyone succeeded in reducing them, but it was their reducibility and not their clarity before reduction that showed them to be compatible with physicalism.
     From: Hartry Field (Tarski's Theory of Truth [1972], §5)
19. Language / B. Reference / 3. Direct Reference / b. Causal reference
Field says reference is a causal physical relation between mental states and objects [Field,H, by Putnam]
     Full Idea: In Field's view reference is a 'physicalistic relation', i.e. a complex causal relation between words or mental representations and objects or sets of objects; it is up to physical science to discover what that physicalistic relation is.
     From: report of Hartry Field (Tarski's Theory of Truth [1972]) by Hilary Putnam - Reason, Truth and History Ch.2
     A reaction: I wouldn't hold your breath while the scientists do their job. If physicalism is right then Field is right, but physics seems no more appropriate for giving a theory of reference than it does for giving a theory of music.