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Single Idea 14129

[filed under theme 6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / c. Priority of numbers ]

Full Idea

Ordinals presuppose serial and one-one relations, whereas cardinals only presuppose one-one relations.

Gist of Idea

Ordinals presuppose two relations, where cardinals only presuppose one

Source

Bertrand Russell (The Principles of Mathematics [1903], §232)

Book Ref

Russell,Bertrand: 'Principles of Mathematics' [Routledge 1992], p.243


A Reaction

This seems to award the palm to the cardinals, for their greater logical simplicity, but I have already given the award to the ordinals in the previous idea, and I am not going back on that.

Related Idea

Idea 14128 Some claim priority for the ordinals over cardinals, but there is no logical priority between them [Russell]


The 19 ideas with the same theme [which type of numbers is the most fundamental?]:

One is prior to two, because its existence is implied by two [Aristotle]
God made the integers, all the rest is the work of man [Kronecker]
Dedekind defined the integers, rationals and reals in terms of just the natural numbers [Dedekind, by George/Velleman]
Order, not quantity, is central to defining numbers [Dedekind, by Monk]
Ordinals can define cardinals, as the smallest ordinal that maps the set [Dedekind, by Heck]
Cantor took the ordinal numbers to be primary [Cantor, by Tait]
Quantity is inconceivable without the idea of addition [Frege]
Could a number just be something which occurs in a progression? [Russell, by Hart,WD]
Some claim priority for the ordinals over cardinals, but there is no logical priority between them [Russell]
Ordinals presuppose two relations, where cardinals only presuppose one [Russell]
Properties of numbers don't rely on progressions, so cardinals may be more basic [Russell]
Von Neumann treated cardinals as a special sort of ordinal [Neumann, by Hart,WD]
Addition of quantities is prior to ordering, as shown in cyclic domains like angles [Dummett]
Ordinals seem more basic than cardinals, since we count objects in sequence [Dummett]
If numbers are basically the cardinals (Frege-Russell view) you could know some numbers in isolation [Benacerraf]
Benacerraf says numbers are defined by their natural ordering [Benacerraf, by Fine,K]
A cardinal is the earliest ordinal that has that number of predecessors [Bostock]
One could grasp numbers, and name sizes with them, without grasping ordering [Wright,C]
The natural numbers are primitive, and the ordinals are up one level of abstraction [Friend]