more from this thinker     |     more from this text


Single Idea 15917

[filed under theme 6. Mathematics / A. Nature of Mathematics / 5. The Infinite / h. Ordinal infinity ]

Full Idea

The paradox of the largest ordinal (the 'Burali-Forti') is that the class of all ordinal numbers is apparently well-ordered, and so it has an ordinal number as order type, which must be the largest ordinal - but all ordinals can be increased by one.

Gist of Idea

Paradox: the class of all ordinals is well-ordered, so must have an ordinal as type - giving a bigger ordinal

Source

Shaughan Lavine (Understanding the Infinite [1994], III.5)

Book Ref

Lavine,Shaughan: 'Understanding the Infinite' [Harvard 1994], p.61

Related Idea

Idea 15918 Paradox: there is no largest cardinal, but the class of everything seems to be the largest [Lavine]


The 9 ideas with the same theme [infinity as an unending ordered series]:

Cantor's theory concerns collections which can be counted, using the ordinals [Cantor, by Lavine]
Cantor extended ordinals into the transfinite, and they can thus measure infinite cardinalities [Cantor, by Maddy]
The number of natural numbers is not a natural number [Frege, by George/Velleman]
ω names the whole series, or the generating relation of the series of ordinal numbers [Russell]
Ordinals are basic to Cantor's transfinite, to count the sets [Lavine]
Paradox: the class of all ordinals is well-ordered, so must have an ordinal as type - giving a bigger ordinal [Lavine]
Raising omega to successive powers of omega reveal an infinity of infinities [Friend]
The first limit ordinal is omega (greater, but without predecessor), and the second is twice-omega [Friend]
Transfinite ordinals are needed in proof theory, and for recursive functions and computability [Hossack]