### Single Idea 10813

#### [catalogued under 4. Formal Logic / F. Set Theory ST / 3. Types of Set / c. Unit (Singleton) Sets]

Full Idea

A new student of set theory has just one thing, the element, and he has another single thing, the singleton, and not the slightest guidance about what one thing has to do with the other.

Gist of Idea

What on earth is the relationship between a singleton and an element?

Source

David Lewis (Mathematics is Megethology [1993], p.12)

Book Reference

-: 'Philosophia Mathematica' [-], p.12