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Single Idea 14242

[filed under theme 4. Formal Logic / F. Set Theory ST / 3. Types of Set / b. Empty (Null) Set ]

Full Idea

Suppose we introduce Ω not as a term standing for a supposed empty set, but as a paradigm of an empty term, not standing for anything.

Gist of Idea

Maybe we can treat the empty set symbol as just meaning an empty term

Source

Oliver,A/Smiley,T (What are Sets and What are they For? [2006], 1.2)

Book Ref

'Metaphysics (Philosophical Perspectives 20)', ed/tr. Hawthorne,John [Blackwell 2006], p.131


A Reaction

This proposal, which they go on to explore, seems to mean that Ω (i.e. the traditional empty set symbol) is no longer part of set theory but is part of semantics.


The 10 ideas from Oliver,A/Smiley,T

If you only refer to objects one at a time, you need sets in order to refer to a plurality [Oliver/Smiley]
We can use plural language to refer to the set theory domain, to avoid calling it a 'set' [Oliver/Smiley]
The empty set is usually derived from Separation, but it also seems to need Infinity [Oliver/Smiley]
The empty set is something, not nothing! [Oliver/Smiley]
We don't need the empty set to express non-existence, as there are other ways to do that [Oliver/Smiley]
Maybe we can treat the empty set symbol as just meaning an empty term [Oliver/Smiley]
The unit set may be needed to express intersections that leave a single member [Oliver/Smiley]
Logical truths are true no matter what exists - but predicate calculus insists that something exists [Oliver/Smiley]
If mathematics purely concerned mathematical objects, there would be no applied mathematics [Oliver/Smiley]
Sets might either represent the numbers, or be the numbers, or replace the numbers [Oliver/Smiley]