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Single Idea 13891

[filed under theme 6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / f. Cardinal numbers ]

Full Idea

Benacerraf claims that the concept of a progression is in some way the fundamental arithmetical notion, essential to understanding the idea of a finite cardinal, with a grasp of progressions sufficing for grasping finite cardinals.

Gist of Idea

To understand finite cardinals, it is necessary and sufficient to understand progressions

Source

report of Paul Benacerraf (What Numbers Could Not Be [1965]) by Crispin Wright - Frege's Concept of Numbers as Objects 3.xv

Book Ref

Wright,Crispin: 'Frege's Conception of Numbers' [Scots Philosophical Monographs 1983], p.117


A Reaction

He cites Dedekind (and hence the Peano Axioms) as the source of this. The interest is that progression seems to be fundamental to ordianls, but this claims it is also fundamental to cardinals. Note that in the first instance they are finite.


The 24 ideas from 'What Numbers Could Not Be'

Benacerraf says numbers are defined by their natural ordering [Benacerraf, by Fine,K]
To understand finite cardinals, it is necessary and sufficient to understand progressions [Benacerraf, by Wright,C]
Disputes about mathematical objects seem irrelevant, and mathematicians cannot resolve them [Benacerraf, by Friend]
No particular pair of sets can tell us what 'two' is, just by one-to-one correlation [Benacerraf, by Lowe]
A set has k members if it one-one corresponds with the numbers less than or equal to k [Benacerraf]
We can count intransitively (reciting numbers) without understanding transitive counting of items [Benacerraf]
Someone can recite numbers but not know how to count things; but not vice versa [Benacerraf]
The application of a system of numbers is counting and measurement [Benacerraf]
To explain numbers you must also explain cardinality, the counting of things [Benacerraf]
For Zermelo 3 belongs to 17, but for Von Neumann it does not [Benacerraf]
The successor of x is either x and all its members, or just the unit set of x [Benacerraf]
Numbers can't be sets if there is no agreement on which sets they are [Benacerraf]
Number words are not predicates, as they function very differently from adjectives [Benacerraf]
The set-theory paradoxes mean that 17 can't be the class of all classes with 17 members [Benacerraf]
Identity statements make sense only if there are possible individuating conditions [Benacerraf]
If ordinal numbers are 'reducible to' some set-theory, then which is which? [Benacerraf]
If any recursive sequence will explain ordinals, then it seems to be the structure which matters [Benacerraf]
The job is done by the whole system of numbers, so numbers are not objects [Benacerraf]
The number 3 defines the role of being third in a progression [Benacerraf]
Number words no more have referents than do the parts of a ruler [Benacerraf]
Number-as-objects works wholesale, but fails utterly object by object [Benacerraf]
There are no such things as numbers [Benacerraf]
Mathematical objects only have properties relating them to other 'elements' of the same structure [Benacerraf]
How can numbers be objects if order is their only property? [Benacerraf, by Putnam]