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6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / d. Natural numbers

[the positive numbers used in counting]

6 ideas
Cantor presented the totality of natural numbers as finite, not infinite [Cantor, by Mayberry]
     Full Idea: Cantor taught us to regard the totality of natural numbers, which was formerly thought to be infinite, as really finite after all.
     From: report of George Cantor (works [1880]) by John Mayberry - What Required for Foundation for Maths? p.414-2
     A reaction: I presume this is because they are (by definition) countable.
The essence of natural numbers must reflect all the functions they perform [Sicha]
     Full Idea: What is really essential to being a natural number is what is common to the natural numbers in all the functions they perform.
     From: Jeffrey H. Sicha (Counting and the Natural Numbers [1968], 2)
     A reaction: I could try using natural numbers as insults. 'You despicable seven!' 'How dare you!' I actually agree. The question about functions is always 'what is it about this thing that enables it to perform this function'.
There couldn't just be one number, such as 17 [Jubien]
     Full Idea: It makes no sense to suppose there might be just one natural number, say seventeen.
     From: Michael Jubien (Ontology and Mathematical Truth [1977], p.113)
     A reaction: Hm. Not convinced. If numbers are essentially patterns, we might only have the number 'twelve', because we had built our religion around anything which exhibited that form (in any of its various arrangements). Nice point, though.
Only higher-order languages can specify that 0,1,2,... are all the natural numbers that there are [Shapiro]
     Full Idea: The main problem of characterizing the natural numbers is to state, somehow, that 0,1,2,.... are all the numbers that there are. We have seen that this can be accomplished with a higher-order language, but not in a first-order language.
     From: Stewart Shapiro (Foundations without Foundationalism [1991], 9.1.4)
Numbers are identified by their main properties and relations, involving the successor function [MacBride]
     Full Idea: The mathematically significant properties and relations of natural numbers arise from the successor function that orders them; the natural numbers are identified simply as the objects that answer to this basic function.
     From: Fraser MacBride (Structuralism Reconsidered [2007], §1)
     A reaction: So Julius Caesar would be a number if he was the successor of Pompey the Great? I would have thought that counting should be mentioned - cardinality as well as ordinality. Presumably Peano's Axioms are being referred to.
The number series is primitive, not the result of some set theoretic axioms [Almog]
     Full Idea: On Skolem's account, to 'get' the natural numbers - that primal structure - do not 'look for it' as the satisfier of some abstract (set-theoretic) axiomatic essence; start with that primitive structure.
     From: Joseph Almog (Nature Without Essence [2010], 12)
     A reaction: [Skolem 1922 and 1923] Almog says the numbers are just 0,1,2,3,4..., and not some underlying axioms. That makes it sound as if they have nothing in common, and that the successor relation is a coincidence.