Unanswered Questions
89 questions with no upvoted or accepted answers
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Can there be nested possible worlds semantics?
Fairly straightforward question, I'd think: Usually, when we do Modal Logic, we think of propositions as sort of embedded within a framework of possible worlds. What, then, do we make of propositions ...
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4
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Truth/actuality as an operator
Frege claimed that "it is true that" adds nothing to the actual meaning of an assertion, and following him along this line are prosentential theories of truth. However, I wonder if this is ...
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3
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In the usual modal logics, are there tautologies of the form ◊¬X or ¬☐X?
And not when, "Possibly not X," or, "Not necessarily X," are implied by, "Impossibly X," already. But so is it possible to have a tautology be a statement of mere ...
- 16.7k
3
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What kind of homo/isomorphism, if any, applies to a certain pair of pairs of permission types?
The SEP article on deontic logic mentions at least once or twice that there seem to be two types of permissibility (also a difference between "ought" and "must," to note). Over the ...
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3
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1
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Can vague concepts have a modality?
Can vague concepts, which I am thinking of as concepts without boundaries, though there are I assume other ways of thinking about them, be necessary, especially if that modality changes?
Supposing it'...
CommunityBot
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3
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Are there modal operators that don't take a proposition as an argument?
All of the modal propositions I can think of are most reasonably analyzed as a modal operator applied to a proposition, and possibly other arguments. In the following examples, I'll write the ...
- 10.9k
3
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What would we gain by allowing quantification over logical constants?
In first-order logic, we quantify over individuals, and in second-order logic, we quantify over properties. However, could we extend this idea to include quantification over logical connectives, ...
- 548
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Propositions that can't be used to distinguish possible worlds
Are there known ways of formalizing the notion of propositions that can't be targeted by counterfactuals in a coherent way? Or of propositions that are outside the scope of the framework in question?
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2
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Can 𝐅𝐑 be taken for a deontic negation operator (rather than just a specified negation of 𝐎𝐁)?
Presuppositions of the question: beliefs about the ambient structure of negation: I was rethinking the following in light of questions about supervenience, grounding, alterity, and identity:
A ...
- 16.7k
2
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Do universals exist in all possible worlds?
Exactly what it says on the tin: Do abstract objects, like universals for instance, necessarily exist in all possible worlds? To my knowledge, David Lewis held to the opinion that they did (And that ...
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A question on quantified modal logic
I originally posted this on math.stackexchange.com, but I’m cross-posting it since I know there are good modal logicians on here too.
Also, I already asked a similar question here: Identity in ...
- 43.4k
2
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1
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If Zalta objects exist, would there be a contingently abstract obligation?
One of the posits of Zaltaesque object theory (let's call it that, since there is something vaguely Kafkaesque about logicist realism) is that for every set of assertible encoding relations there is ...
CommunityBot
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2
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79
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Infinitary modal logic
Let 'L' and 'M' denote the necessity and possibility operators. In Modal Logic, the following theorems hold:
L(p and q) <--> (Lp and Lq)
(Lp or Lq) --> L(p or q)
M(p or q) <--> (Mp or ...
- 299
2
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platinga's actualism and introduction of essences
I am reading Plantinga's "Actualism and Possible Worlds" and I am struggling to see why he needs to introduce his idea of essences to resolve the following issue:
The actualist holds that:
(...
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2
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Entry points from philosophy into mathematics at higher levels?
Everytime I look up of the link between philosophy and mathematics, I see the topics only of the most foundational levels discussed. As in logic, and stuff. When I study higher mathematics theories, ...
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