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Single Idea 14670

[filed under theme 4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic ]

Full Idea

Metaphysical modal logic concerns metaphysical (or alethic) necessity and metaphysical (alethic) possibility, or necessity and possibility tout court - as opposed to such other types of modality as physical necessity, epistemic necessity etc.

Clarification

'tout court' means 'simply'

Gist of Idea

Metaphysical (alethic) modal logic concerns simple necessity and possibility (not physical, epistemic..)

Source

Nathan Salmon (The Logic of What Might Have Been [1989], Intro n2)

Book Ref

Salmon,Nathan: 'Metaphysics, Mathematics and Meaning' [OUP 2005], p.130


The 11 ideas with the same theme [inference from truths concerning necessity and possibility]:

There are three different deductions for actual terms, necessary terms and possible terms [Aristotle]
Modal logic is not an extensional language [Parsons,C]
For modality Lewis rejected boxes and diamonds, preferring worlds, and an index for the actual one [Lewis, by Stalnaker]
Metaphysical (alethic) modal logic concerns simple necessity and possibility (not physical, epistemic..) [Salmon,N]
The modal logic of C.I.Lewis was only interpreted by Kripke and Hintikka in the 1960s [Jacquette]
The main modal logics disagree over three key formulae [Yablo]
Modality affects content, because P→◊P is valid, but ◊P→P isn't [Fitting/Mendelsohn]
S4: 'poss that poss that p' implies 'poss that p'; S5: 'poss that nec that p' implies 'nec that p' [Orenstein]
Possible worlds logics use true-in-a-world rather than true [Girle]
Modal logic has four basic modal negation equivalences [Girle]
Modal logics were studied in terms of axioms, but now possible worlds semantics is added [Girle]