Questions tagged [possible-worlds]

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Looking for help understanding modal logic and graph structure

I'm a novice to modal logic and only have a passing familiarity with classical logic. I started reading 'Modal Logic for Open Minds'. It is very readable, but then on page 16 the author introduces a ...
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Does Human Pride degrade Peace? [closed]

I've been thinking about this question, and I think the reason countries go to war with each other is for their own pride, people die for their own pride. So if the entire world is one country and we ...
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Is it the fact that we have language that causes us to believe in possible worlds?

I am not quite sure whether this belongs in Philosophy SE, but I couldn't think of a better SE, so I am posting it here. My question is, is it the fact that we have language that causes us to believe ...
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Cardinality of the logical space according to David Lewis

I just read an extract of David Lewis's Counterfactuals and he claims there in a footnote on page 90 that there are at least beth_2 possible worlds. He also claims in the very same footnote that "...
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If something is Possible is it therefore Necessary?

Does anybody agree on this: “Given an infinite time Y, every possible event X needs to happen, right?” From a mathematical point of view it seems OK to me, although depending on the idea we have of ...
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How should you live when you have options?

If you have the opportunity to earn money easily (for example just doing dropshipping, or selling oil reserve) which requires less self control and discipline. And the other is by doing difficult job (...
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Alternativeness... or not?

We recognize as an axiom that events in our reality can occur in different ways. It is about facts, models that combine facts and our reactions. I call it alternativeness. Here I will not ask: whether ...
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Logical/mathematical (non-physical) arguments against simulation hypothesis?

So the Simulation Hypothesis, from what I've heard, is not scientifically testable because it is not falsifiable, which makes perfect sense to me and is the viewpoint I have always adopted. Yet ...
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Stances on possible worlds

Modal realism is the belief that all possible worlds actually exist. Actualism is the belief that possible worlds don’t exist at all. What are some examples of modal-metaphysical views which try to ...
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Is there a Possible World in which Humeanism isn't true?

I'm an amateur philosopher, interested in the work of Ned Hall: Mindscape podcast: Ned Hall on Possible Worlds and the Laws of Nature (Dec-2019) PhilPapers: Humean Reductionism About Laws Of Nature (...
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State description in PWS

A very short question: If, following Carnap, we can represent a possible world as a state description starting from a quantified language L, why does it make sense, following standard modal logic, to ...
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Propositions as set of possible worlds in FOL

In possible world semantics for propositional calculus, possible worlds are usually taken to be models for propositional formulas (the set of valuations in which a certain formula is true) In first ...
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Can truths about the natural numbers vary across possible worlds?

The truths of logic are the same in all possible worlds. However, what about truths about natural numbers? Like, for instance, is there a world where there are only finitely many primes, or a world ...
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Is my name a rigid designator if I had an identical twin in a possible world?

In examples I have read defining the term "rigid designator," proper names are used as an example, e.g. Aristotle vs the author of the Nicomachean Ethics. I could well be overanalyzing what ...
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Why are some things considered "impossible" even in other universes?

For example, I often hear that life could not develop in a universe where the fundamental constants were even slightly changed, or where certain physical laws were different. But if we're dealing with ...
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Computer vs brain in many-worlds interpretation of QM

Assume that the many-worlds interpretation of quantum mechanics is true. A classical computer that is modeled on the Turing machine is designed to perform exactly the same computation in each of the ...
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Are there set-theoretical problems with modal metaphysics?

I'm trying to learn about modal logic and the metaphysics of modality, and there's something that has been bugging me about what I've read so far: are there set-theoretical issues with supposing we ...
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Could there be a universe where the concept of order and logic and numbers and objects and space and time don't exist?

Could there be a universe where the concept of order and logic and numbers and objects and space and time don't exist ? This would preclude math as we know it. Maybe there is something better than ...
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How does one determine if killing an evil creature is an evil act?

I wanted to ask you in my D&D game, we fought some goblins. They attacked us first. We killed most of them; my character gave the rest a chance to surrender and said he may let them go. He ...
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Is there any philosophy which proposes that whatever you believe or imagine is true or exists?

Every day, we have conflicts with almost everyone about what we think and what we believe (there are religious conflicts, conflicts of opinions...). Also, there are people who think about alternative ...
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what is meaning of accessibility of possible worlds?

I have a question about the notion of possibility in modal logic. There are systems and worlds with this notion. They say that a world w1 is accessible to an other world w2 if and only if for any true ...
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Having S5 system Why we need to use WPSR in Gale Pruss New cosmological arguement?

As you know Gale_ Pruss improved The cosmological argument using WPSR instead of Strong PSR. They in their 1999 article said if it be possibly that there be a God who freely created the world using ...
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Does denying the Limit Assumption in counterfactual logic lead to contradiction?

According to the similarity semantics for counterfactuals, a counterfactual A > C is true iff on the most similar class of worlds to the actual world (or any given world the counterfactual's truth ...
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What is Robert Nozick alluding to by a “vast generalization” of Feynman’s path integral?

I was reading a book from the philosopher Robert Nozick (Invariances: The Structure of the Objective World), and there was something that confused me. Around page 159 he argues that every logically ...
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What is the procentual probability that we live in the objective reality independent of our consciousness rather than in some virtual reality?

I am aware than it is impossible to prove anything in real life. Therefore we can't prove that the picture of the reality we are percieving through our senses is a subjective picture of an objective ...
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Did Carnap propose some kind of Modal Realism?

I have read in several pages that Rudolf Carnap, just as David Lewis (The creator of Modal Realism philosophical hypothesis) proposed that every logical proposition exists as a universe But is this ...
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David Lewis and naturalism

I am studying Lewis and I am wondering what are the cornerstones of his philosophical perspective. In particular, I am wondering if Lewis is a naturalist like his supervisor Quine.
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Can a Rigid Designator still exist if there is only one possible world?

According to Kripke, a rigid designator is a pronoun (but not all pronouns are rigid designators) and they pick out the same unique individual in each possible world. I understand this, however, if ...
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Modal logics - philosophical paradoxes using modeling by possible worlds

I'm searching for "paradoxes" in classical modal logics, meaning lines of reasoning which give a counterintuitive conclusion if performed in classical logic, which can be modelled by the (semantical) ...
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Is there any physics-model version of Tegmark's hypothesis?

Tegmark's mathematical universe hypothesis is very interesting (https://en.m.wikipedia.org/wiki/Mathematical_universe_hypothesis) but it has virtually no support among physicists because it is too ...
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Is it possible to mathematically define a hypercomputer-universe where things that could not be computed by it could exist? [duplicate]

There are a few physicists that propose that the universe is a hypercomputer. One example is Roger Penrose, who, basing in his quantum interpretation (https://en.wikipedia.org/wiki/...
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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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Can many worlds interpretation have universes with different laws?

The Many Worlds Interpretation of quantum mechanics is classified by Max Tegmark as a level-3 multiverse hypothesis. This means that in the universes that it will predict, there could be different ...
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How does this anthropic principle argument from Schopenhauer make any sense?

According to a blog post This is what another universe looks like, "in Arthur Schopenhauer's 1844 work "Von der Nichtigkeit und dem Leiden des Lebens", he argues that our world must be the worst of ...
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Can Schmidhuber's hypothesis reproduce all types of universes? And Wheeler's it from bit? Or Weizsäcker's ur-theory?

I found a paper that talked about paraconsistent logic systems (https://en.wikipedia.org/wiki/Paraconsistent_logic) and trivialist systems (https://en.wikipedia.org/wiki/Trivialism) and the ...
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Does Tegmark himself include paraconsistent mathematical structures in his mathematical multiverse hypothesis?

Tegmark postulates in his hypothesis that all possible mathematical structures would exist. But does he include also possible mathematical structures described by other types of logic like ...
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Did David Deutsch really disprove the Simulation Hypothesis?

In The Fabric of Reality (1997) by David Deutsch, he says: Imagine a computer built to render every possible Virtual Reality. Suppose all possible environments produced by this generator can be ...
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Does Tegmark's Mathematical Universe hypothesis allow existence of alternative mathematics?

Tegmark's mathematical multiverse hypothesis assumes that all mathematical structures exist as universes But do you know whether his hypothesis also allows/accept universes described by other types ...
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5 votes
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Can possible-but-non-actual objects have accidental properties?

The modal logic I am considering is the "Simplest Quantified Modal Logic" which combines first-order predicate logic with identity, with S5 in the most straightforward way, described here and slightly ...
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How could we get a world where only impossible things happen? [closed]

Imagine a universe where 1+1=3. This contradiction would trigger the effects of the principle of explosion, and thus, literally everything (possible and impossible things) could happen. If we lived in ...
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4 votes
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Is essentialism compatible with naturalism?

I am not an expert and I cannot understand why essentialism is incompatible with naturalism? Why scientific laws cannot describe essential properties of objects?
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What's the difference between logical modalities and physical modalities?

I am just wondering what's the difference between the two. I would say that there is something different, but honestly I can't define what it is exactly. What do you think?
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What is the Lange's viewpoint on laws of nature?

I am just wondering what is the Lange's philosophical perspective on laws of nature and what line of thought he follows in the contemporary debate.
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Do Alexius Meinong's impossible worlds describe all impossible worlds/things? [duplicate]

Does his impossible worlds category include (and can describe) literally all impossible things/worlds? Inconsistencies, paradoxes, impossible solutions to problems (and impossible problems); really ...
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Why can we not reduce necessity to analyticity?

Why can’t we eliminate talk of necessity and possible worlds, for talk of analyticity and (non-modal) logical consistency? Has there been any attempt in recent times to do this? I'm not 100% sure, but ...
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If we imagine a world that functions without causality, how absurd could it be?

If we assume that there's a universe that is devoid of causality, and if we assume that it isn't eternally static, would that mean that everything can happen because there are no reasons inhibiting ...
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3 votes
7 answers
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Is there an idea of non-spatial reality in philosophy?

Our world is spatial. In particular there are 3 dimensions and we can measure lengths of objects in either of them. However, when thinking about metaphysics I came to the conclusion that there might ...
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How does the concept of the 'virtual' (Deleuze) relate to 'counterfactuals' (Lewis)?

We read: "[...] Deleuze will reject the notion of the possible in favor of that of the virtual. Rather than awaiting realization, the virtual is fully real; what happens in genesis is that the ...
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Ontological status of Axiom of Choice

Mathematical facts are necessary truths, either in a Platonic sense or by way of axioms. In the latter sense I mean that the Peano Axioms prove that 2+3=5, for example. In other words, "PA ⊨ 2+3=5"...
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circularity of possibility defined over possible worlds

I have just checked similar questions that have been asked(and answered) before but I am still confused. How is it that the notion of possibility defined over as being True in some possible world not ...
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