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Single Idea 15513

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

Full Idea

Maybe the singleton of something x is not an atom, but consists of x plus a lasso. That gives a singleton an internal structure. ...But what do we know of the nature of the lasso, or how it fits? We are no better off.

Gist of Idea

Maybe singletons have a structure, of a thing and a lasso?

Source

David Lewis (Parts of Classes [1991], 2.5)

Book Ref

Lewis,David: 'Parts of Classes' [Blackwell 1991], p.43


A Reaction

[second bit on p.45]


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]