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Single Idea 8693
[filed under theme 18. Thought / E. Abstraction / 7. Abstracta by Equivalence
]
Full Idea
Hume's Principle has a structure Boolos calls an 'abstraction principle'. Within the scope of two universal quantifiers, a biconditional connects an identity between two things and an equivalence relation. It says we don't care about other differences.
Clarification
Hume's Principle says numbers are identical through one-to-one correspondence
Gist of Idea
An 'abstraction principle' says two things are identical if they are 'equivalent' in some respect
Source
George Boolos (Is Hume's Principle analytic? [1997]), quoted by Michèle Friend - Introducing the Philosophy of Mathematics 3.7
Book Ref
Friend,Michèle: 'Introducing the Philosophy of Mathematics' [Acumen 2007], p.75
A Reaction
This seems to be the traditional principle of abstraction by ignoring some properties, but dressed up in the clothes of formal logic. Frege tries to eliminate psychology, but Boolos implies that what we 'care about' is relevant.
The
31 ideas
from George Boolos
10482
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The logic of ZF is classical first-order predicate logic with identity
[Boolos]
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10483
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Mathematics and science do not require very high orders of infinity
[Boolos]
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10484
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The iterative conception says sets are formed at stages; some are 'earlier', and must be formed first
[Boolos]
|
10485
|
Naïve sets are inconsistent: there is no set for things that do not belong to themselves
[Boolos]
|
10488
|
It is lunacy to think we only see ink-marks, and not word-types
[Boolos]
|
10487
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I am a fan of abstract objects, and confident of their existence
[Boolos]
|
10489
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We deal with abstract objects all the time: software, poems, mistakes, triangles..
[Boolos]
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10490
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Mathematics isn't surprising, given that we experience many objects as abstract
[Boolos]
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10491
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Infinite natural numbers is as obvious as infinite sentences in English
[Boolos]
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10492
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A few axioms of set theory 'force themselves on us', but most of them don't
[Boolos]
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8693
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An 'abstraction principle' says two things are identical if they are 'equivalent' in some respect
[Boolos]
|
13547
|
Limitation of Size is weak (Fs only collect is something the same size does) or strong (fewer Fs than objects)
[Boolos, by Potter]
|
18192
|
Do the Replacement Axioms exceed the iterative conception of sets?
[Boolos, by Maddy]
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14249
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Boolos reinterprets second-order logic as plural logic
[Boolos, by Oliver/Smiley]
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13841
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Why should compactness be definitive of logic?
[Boolos, by Hacking]
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10829
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A sentence can't be a truth of logic if it asserts the existence of certain sets
[Boolos]
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10830
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Second-order logic metatheory is set-theoretic, and second-order validity has set-theoretic problems
[Boolos]
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10832
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'∀x x=x' only means 'everything is identical to itself' if the range of 'everything' is fixed
[Boolos]
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10833
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Many concepts can only be expressed by second-order logic
[Boolos]
|
10834
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Weak completeness: if it is valid, it is provable. Strong: it is provable from a set of sentences
[Boolos]
|
13671
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Second-order quantifiers are just like plural quantifiers in ordinary language, with no extra ontology
[Boolos, by Shapiro]
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10267
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We should understand second-order existential quantifiers as plural quantifiers
[Boolos, by Shapiro]
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7806
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Boolos invented plural quantification
[Boolos, by Benardete,JA]
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10225
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Monadic second-order logic might be understood in terms of plural quantifiers
[Boolos, by Shapiro]
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7785
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The use of plurals doesn't commit us to sets; there do not exist individuals and collections
[Boolos]
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10736
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Boolos showed how plural quantifiers can interpret monadic second-order logic
[Boolos, by Linnebo]
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10780
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Any sentence of monadic second-order logic can be translated into plural first-order logic
[Boolos, by Linnebo]
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10697
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Identity is clearly a logical concept, and greatly enhances predicate calculus
[Boolos]
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10698
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Plural forms have no more ontological commitment than to first-order objects
[Boolos]
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10699
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Does a bowl of Cheerios contain all its sets and subsets?
[Boolos]
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10700
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First- and second-order quantifiers are two ways of referring to the same things
[Boolos]
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