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Single Idea 13711

[filed under theme 4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / f. System B ]

Full Idea

With system B we begin to be able to say something about iterated modalities. ..S4 then takes a different stand on the iterated modalities, and neither is an extension of the other.

Gist of Idea

System B introduces iterated modalities

Source

Theodore Sider (Logic for Philosophy [2010], 6.4.4)

Book Ref

Sider,Theodore: 'Logic for Philosophy' [OUP 2010], p.168

Related Idea

Idea 13704 It is hard to say which are the logical truths in modal logic, especially for iterated modal operators [Sider]

The 5 ideas with the same theme [version imposing two conditions on accessibility]:

14667 System B has not been justified as fallacy-free for reasoning on what might have been [Salmon,N]
14668 In B it seems logically possible to have both p true and p is necessarily possibly false [Salmon,N]
14692 System B implies that possibly-being-realized is an essential property of the world [Salmon,N]
9745 The system B has the 'reflexive' and 'symmetric' conditions on its accessibility relation [Fitting/Mendelsohn]
13711 System B introduces iterated modalities [Sider]