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Single Idea 15497

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

Full Idea

Given the theory of part and whole, the member-singleton relation may replace membership generally as the primitive notion of set theory.

Gist of Idea

We can replace the membership relation with the member-singleton relation (plus mereology)

Source

David Lewis (Parts of Classes [1991], Pref)

Book Ref

Lewis,David: 'Parts of Classes' [Blackwell 1991], p.-3


A Reaction

An obvious question is to ask what the member-singleton relation is if it isn't membership.

Related Idea

Idea 15496 We can build set theory on singletons: classes are then fusions of subclasses, membership is the singleton [Lewis]


The 12 ideas with the same theme [status of a set having a single member]:

If a set is 'a many thought of as one', beginners should protest against singleton sets [Cantor, by Lewis]
Normally a class with only one member is a problem, because the class and the member are identical [Russell]
The singleton is defined using the pairing axiom (as {x,x}) [Enderton]
What on earth is the relationship between a singleton and an element? [Lewis]
Are all singletons exact intrinsic duplicates? [Lewis]
We can replace the membership relation with the member-singleton relation (plus mereology) [Lewis]
If we don't understand the singleton, then we don't understand classes [Lewis]
If singleton membership is external, why is an object a member of one rather than another? [Lewis]
Maybe singletons have a structure, of a thing and a lasso? [Lewis]
What is special about Bill Clinton's unit set, in comparison with all the others? [Chihara]
What is a singleton set, if a set is meant to be a collection of objects? [Szabó]
The unit set may be needed to express intersections that leave a single member [Oliver/Smiley]