Full Idea
Cantor's work revealed that the notion of an ordinal number is more fundamental than that of a cardinal number.
Gist of Idea
Cantor showed that ordinals are more basic than cardinals
Source
report of George Cantor (works [1880]) by Michael Dummett - Frege philosophy of mathematics Ch.23
Book Reference
Dummett,Michael: 'Frege: philosophy of mathematics' [Duckworth 1991], p.293
A Reaction
Dummett makes it sound like a proof, which I find hard to believe. Is the notion that I have 'more' sheep than you logically prior to how many sheep we have? If I have one more, that implies the next number, whatever that number may be. Hm.