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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 'What are Sets and What are they For?'

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]