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9766
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Study vagueness first by its logic, then by its truth-conditions, and then its metaphysics [Fine,K]
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Full Idea:
My investigation of vagueness began with the question 'What is the correct logic of vagueness?', which led to the further question 'What are the correct truth-conditions for a vague language?', which led to questions of meaning and existence.
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From:
Kit Fine (Vagueness, Truth and Logic [1975], Intro)
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A reaction:
This is the most perfect embodiment of the strategy of analytical philosophy which I have ever read. It is the strategy invented by Frege in the 'Grundlagen'. Is this still the way to go, or has this pathway slowly sunk into the swamp?
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9775
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Excluded Middle, and classical logic, may fail for vague predicates [Fine,K]
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Full Idea:
Maybe classical logic fails for vagueness in Excluded Middle. If 'H bald ∨ ¬(H bald)' is true, then one disjunct is true. But if the second is true the first is false, and the sentence is either true or false, contrary to the borderline assumption.
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From:
Kit Fine (Vagueness, Truth and Logic [1975], 4)
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A reaction:
Fine goes on to argue against the implication that we need a special logic for vague predicates.
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14234
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If you only refer to objects one at a time, you need sets in order to refer to a plurality [Oliver/Smiley]
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Full Idea:
A 'singularist', who refers to objects one at a time, must resort to the language of sets in order to replace plural reference to members ('Henry VIII's wives') by singular reference to a set ('the set of Henry VIII's wives').
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From:
Oliver,A/Smiley,T (What are Sets and What are they For? [2006], Intro)
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A reaction:
A simple and illuminating point about the motivation for plural reference. Null sets and singletons give me the creeps, so I would personally prefer to avoid set theory when dealing with ontology.
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14237
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We can use plural language to refer to the set theory domain, to avoid calling it a 'set' [Oliver/Smiley]
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Full Idea:
Plurals earn their keep in set theory, to answer Skolem's remark that 'in order to treat of 'sets', we must begin with 'domains' that are constituted in a certain way'. We can speak in the plural of 'the objects', not a 'domain' of objects.
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From:
Oliver,A/Smiley,T (What are Sets and What are they For? [2006], Intro)
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A reaction:
[Skolem 1922:291 in van Heijenoort] Zermelo has said that the domain cannot be a set, because every set belongs to it.
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14246
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If mathematics purely concerned mathematical objects, there would be no applied mathematics [Oliver/Smiley]
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Full Idea:
If mathematics was purely concerned with mathematical objects, there would be no room for applied mathematics.
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From:
Oliver,A/Smiley,T (What are Sets and What are they For? [2006], 5.1)
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A reaction:
Love it! Of course, they are using 'objects' in the rather Fregean sense of genuine abstract entities. I don't see why fictionalism shouldn't allow maths to be wholly 'pure', although we have invented fictions which actually have application.
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14247
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Sets might either represent the numbers, or be the numbers, or replace the numbers [Oliver/Smiley]
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Full Idea:
Identifying numbers with sets may mean one of three quite different things: 1) the sets represent the numbers, or ii) they are the numbers, or iii) they replace the numbers.
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From:
Oliver,A/Smiley,T (What are Sets and What are they For? [2006], 5.2)
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A reaction:
Option one sounds the most plausible to me. I will take numbers to be patterns embedded in nature, and sets are one way of presenting them in shorthand form, in order to bring out what is repeated.
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9768
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Vagueness is semantic, a deficiency of meaning [Fine,K]
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Full Idea:
I take vagueness to be a semantic feature, a deficiency of meaning. It is to be distinguished from generality, undecidability, and ambiguity.
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From:
Kit Fine (Vagueness, Truth and Logic [1975], Intro)
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A reaction:
Sounds good. If we cut nature at the joints with our language, then nature is going to be too subtle and vast for our finite and gerrymandered language, and so it will break down in tricky situations. But maybe epistemology precedes semantics?
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9776
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A thing might be vaguely vague, giving us higher-order vagueness [Fine,K]
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Full Idea:
There is a possibility of 'higher-order vagueness'. The vague may be vague, or vaguely vague, and so on. If J has few hairs on his head than H, then he may be a borderline case of a borderline case.
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From:
Kit Fine (Vagueness, Truth and Logic [1975], 5)
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A reaction:
Such slim grey areas can also be characterised as those where you think he is definitely bald, but I am not so sure.
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9770
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Logical connectives cease to be truth-functional if vagueness is treated with three values [Fine,K]
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Full Idea:
With a three-value approach, if P is 'blob is pink' and R is 'blob is red', then P&P is indefinite, but P&R is false, and P∨P is indefinite, but P∨R is true. This means the connectives & and ∨ are not truth-functional.
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From:
Kit Fine (Vagueness, Truth and Logic [1975], 1)
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A reaction:
The point is that there could then be no logic in any way classical for vague sentences and three truth values. A powerful point.
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9773
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With the super-truth approach, the classical connectives continue to work [Fine,K]
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Full Idea:
With the super-truth approach, if P is 'blob is pink' and R is 'blob is red', then P&R is false, and P∨R is true, since one of P and R is true and one is false in any complete and admissible specification. It encompasses all 'penumbral truths'.
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From:
Kit Fine (Vagueness, Truth and Logic [1975], 3)
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A reaction:
[See Idea 9767 for the super-truth approach, and Idea 9770 for a contrasting view] The approach, which seems quite appealing, is that we will in no circumstances give up basic classical logic, but we will make maximum concessions to vagueness.
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