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Single Idea 9910

[filed under theme 6. Mathematics / C. Sources of Mathematics / 1. Mathematical Platonism / b. Against mathematical platonism ]

Full Idea

The identification of numbers with objects works wholesale but fails utterly object by object.

Gist of Idea

Number-as-objects works wholesale, but fails utterly object by object

Source

Paul Benacerraf (What Numbers Could Not Be [1965], IIIC)

Book Ref

'Philosophy of Mathematics: readings (2nd)', ed/tr. Benacerraf/Putnam [CUP 1983], p.292


A Reaction

This seems to be a glaring problem for platonists. You can stare at 1728 till you are blue in the face, but it only begins to have any properties at all once you examine its place in the system. This is unusual behaviour for an object.

Related Idea

Idea 9964 Since mathematical objects are essentially relational, they can't be picked out on their own [Jubien]


The 31 ideas from Paul Benacerraf

If numbers are basically the cardinals (Frege-Russell view) you could know some numbers in isolation [Benacerraf]
Obtaining numbers by abstraction is impossible - there are too many; only a rule could give them, in order [Benacerraf]
We must explain how we know so many numbers, and recognise ones we haven't met before [Benacerraf]
An adequate account of a number must relate it to its series [Benacerraf]
Realists have semantics without epistemology, anti-realists epistemology but bad semantics [Benacerraf, by Colyvan]
Mathematical truth is always compromising between ordinary language and sensible epistemology [Benacerraf]
The platonist view of mathematics doesn't fit our epistemology very well [Benacerraf]
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]
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]
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]
Numbers can't be sets if there is no agreement on which sets they are [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]
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]
Number-as-objects works wholesale, but fails utterly object by object [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]
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]