Possible universes as in Modal Logics

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In summary, the conversation discusses the connection between the number of possible modal logics and the number of possible universes. It is suggested that for every possible universe, there is a suitable modal logic to describe it. However, it is questioned whether the reverse is also true. The conversation also touches on the relevance of these logics to physicists and the relationship between logicians and physicists. Finally, the idea of a theory of everything and its potential for being proven through experiments is mentioned. The speaker concludes that continuous learning and reevaluation is necessary, as there may never be an ultimate destination for knowledge.
  • #1
MathematicalPhysicist
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It seems to me quite plausible to find some similarities between the number of possible modal logics and the number of possible universes.
For every possible universe you can find a suitable modal logic that describes it.

But is it also true that for any modal logic there exists a universe that is described by it?

I mean think of infinitude of universes, the place where metaphysics meets physics.
Are physicists interested in these sort of logics?
Is there a bridge between logicians and physicists?

Well as Michio Kaku once said:"can a theory of everything be proven by experiment?".

I guess that the answer to this is "No", you cannot make endless experiments to probe every possible universe, but you cannot also find such a theory of everything, cause there are an infinite number of models and modalities.
The search for a theory of everything is futile...
 
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  • #2
Perhaps seeking knowledge is futile. Have not studied semantics, epistemology nor existentialism in many years, the former somewhat subsumed in semiotics, but can comment that these modes of thinking remain useful tools, not descriptions of reality. Physics strives to describe what actually exists within the limits of our instruments despite epistemic flaws.

I am serene knowing I must continuously study, learn, reevaluate knowledge without arriving at an ultimate destination.
 
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  • #3
MathematicalPhysicist said:
But is it also true that for any modal logic there exists a universe that is described by it?
Not necessarily. We only have evidence for one universe. And, some modal logics might not be generalizable in that fashion. We've pretty much moved beyond Plato's idea that everything we can imagine exists.
MathematicalPhysicist said:
Are physicists interested in these sort of logics?
Perhaps a few, but not many. Maybe a few hundred or less.
MathematicalPhysicist said:
Is there a bridge between logicians and physicists?
Yes. The logicians usually call themselves mathematicians or theoretical physicists when engaged in this activity, however. Almost nobody in academia or science identifies professional as a logician anymore. Very few have since the 1700s or so (coinciding with the replacement of "natural philosophy" with "science" as the dominant discipline studying the physical world), and since the 1970s that number is dwindled further. Plenty of philosophers and mathematicians still use formal logic, but they just don't identify that way. "Category theorist" is a popular description that overlaps heavily with "logicians" using "modal logics" in the sense that you are using it, although they aren't identical. Abstract algebra also heavily overlaps with it.
MathematicalPhysicist said:
Well as Michio Kaku once said:"can a theory of everything be proven by experiment?".
Depends upon what you mean by proven. It could certainly predict everything in the Standard Model and GR and additional things specific to the TOE and if it did that would probably be considered proof of the TOE even though the TOE wasn't necessarily a unique way to produce those results.
 

FAQ: Possible universes as in Modal Logics

What is modal logic?

Modal logic is a type of formal logic that extends classical logic to include modalities, which are expressions of necessity and possibility. It allows for statements not just about what is, but about what could be or must be. Modal logic is used in various fields including philosophy, computer science, and linguistics.

How does modal logic relate to possible worlds?

In modal logic, possible worlds are used as a way to interpret modal statements. A possible world is a complete and consistent way the world could be. When we say something is possible, we mean that there is at least one possible world where it is true. When we say something is necessary, we mean it is true in all possible worlds. This framework helps in understanding and analyzing statements about possibility and necessity.

What are some applications of modal logic?

Modal logic has numerous applications across different fields. In philosophy, it is used to analyze metaphysical concepts like necessity, possibility, and contingency. In computer science, modal logic is applied in the design and verification of software and hardware systems, particularly in temporal logic and dynamic logic. In linguistics, it helps in understanding meaning in natural language, especially in the context of tense and aspect.

Can modal logic address questions about the actual world versus possible worlds?

Yes, modal logic can address questions about the actual world versus possible worlds. It distinguishes between what is true in the actual world and what could be true in some other possible worlds. This distinction is crucial in philosophical debates about necessity and contingency, as well as in practical applications like reasoning about different scenarios in artificial intelligence and decision theory.

What are the different types of modal logics?

There are several types of modal logics, each with its own set of rules and interpretations. Some of the most common include:

  • Propositional Modal Logic: Deals with necessity and possibility operators applied to propositions.
  • Temporal Logic: Focuses on the ordering of events in time, with operators like "always" and "eventually".
  • Deontic Logic: Concerned with obligation and permission, often used in ethical and legal reasoning.
  • Epistemic Logic: Deals with knowledge and belief, used in philosophy and artificial intelligence.
  • Dynamic Logic: Used to reason about actions and their effects, particularly in computer science.
Each type of modal logic has its own syntax and semantics tailored to its specific domain of application.

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