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Single Idea 14128

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

Full Idea

It is claimed that ordinals are prior to cardinals, because they form the progression which is relevant to mathematics, but they both form progressions and have the same ordinal properties. There is nothing to choose in logical priority between them.

Gist of Idea

Some claim priority for the ordinals over cardinals, but there is no logical priority between them

Source

Bertrand Russell (The Principles of Mathematics [1903], §230)

Book Ref

Russell,Bertrand: 'Principles of Mathematics' [Routledge 1992], p.241

A Reaction

We have an intuitive notion of the size of a set without number, but you can't actually start counting without number, so the ordering seems to be the key to the business, which (I would have thought) points to ordinals as prior.

Related Idea

Idea 14129 Ordinals presuppose two relations, where cardinals only presuppose one [Russell]

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

11044 One is prior to two, because its existence is implied by two [Aristotle]
10091 God made the integers, all the rest is the work of man [Kronecker]
10090 Dedekind defined the integers, rationals and reals in terms of just the natural numbers [Dedekind, by George/Velleman]
17452 Ordinals can define cardinals, as the smallest ordinal that maps the set [Dedekind, by Heck]
7524 Order, not quantity, is central to defining numbers [Dedekind, by Monk]
9983 Cantor took the ordinal numbers to be primary [Cantor, by Tait]
18256 Quantity is inconceivable without the idea of addition [Frege]
13510 Could a number just be something which occurs in a progression? [Russell, by Hart,WD]
14128 Some claim priority for the ordinals over cardinals, but there is no logical priority between them [Russell]
14129 Ordinals presuppose two relations, where cardinals only presuppose one [Russell]
14132 Properties of numbers don't rely on progressions, so cardinals may be more basic [Russell]
13489 Von Neumann treated cardinals as a special sort of ordinal [Neumann, by Hart,WD]
18255 Addition of quantities is prior to ordering, as shown in cyclic domains like angles [Dummett]
9191 Ordinals seem more basic than cardinals, since we count objects in sequence [Dummett]
13411 If numbers are basically the cardinals (Frege-Russell view) you could know some numbers in isolation [Benacerraf]
9151 Benacerraf says numbers are defined by their natural ordering [Benacerraf, by Fine,K]
18102 A cardinal is the earliest ordinal that has that number of predecessors [Bostock]
13892 One could grasp numbers, and name sizes with them, without grasping ordering [Wright,C]
8661 The natural numbers are primitive, and the ordinals are up one level of abstraction [Friend]