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Single Idea 10174

[filed under theme 6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers ]

Full Idea

The difficulties for a nominalistic mereological approach to arithmetic is that an infinity of physical objects are needed (space-time points? strokes?), and it must define functions, such as 'successor'.

Gist of Idea

Mereological arithmetic needs infinite objects, and function definitions

Source

E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)


A Reaction

Many ontologically austere accounts of arithmetic are faced with the problem of infinity. The obvious non-platonist response seems to be a modal or if-then approach. To postulate infinite abstract or physical entities so that we can add 3 and 2 is mad.


The 18 ideas from E Reck / M Price

ZFC set theory has only 'pure' sets, without 'urelements' [Reck/Price]
'Analysis' is the theory of the real numbers [Reck/Price]
Peano Arithmetic can have three second-order axioms, plus '1' and 'successor' [Reck/Price]
Structuralism emerged from abstract algebra, axioms, and set theory and its structures [Reck/Price]
Formalist Structuralism says the ontology is vacuous, or formal, or inference relations [Reck/Price]
Set-theory gives a unified and an explicit basis for mathematics [Reck/Price]
Mereological arithmetic needs infinite objects, and function definitions [Reck/Price]
Relativist Structuralism just stipulates one successful model as its arithmetic [Reck/Price]
The existence of an infinite set is assumed by Relativist Structuralism [Reck/Price]
A nominalist might avoid abstract objects by just appealing to mereological sums [Reck/Price]
While true-in-a-model seems relative, true-in-all-models seems not to be [Reck/Price]
Universalist Structuralism is based on generalised if-then claims, not one particular model [Reck/Price]
Universalist Structuralism eliminates the base element, as a variable, which is then quantified out [Reck/Price]
Three types of variable in second-order logic, for objects, functions, and predicates/sets [Reck/Price]
Maybe we should talk of an infinity of 'possible' objects, to avoid arithmetic being vacuous [Reck/Price]
There are 'particular' structures, and 'universal' structures (what the former have in common) [Reck/Price]
Pattern Structuralism studies what isomorphic arithmetic models have in common [Reck/Price]
There are Formalist, Relativist, Universalist and Pattern structuralism [Reck/Price]