Possible Worlds and Modal Realism (explained and debated)

[Music] hello and welcome to philosophy vibe the channel where we discuss and debate different philosophical ideas today we're going to be looking into the idea of possible worlds with a focus on modal realism as argued by the philosopher david lewis fascinating so firstly a bit of background on modality and possible worlds modal statements are those concerning necessity and possibility in philosophy we consider certain statements to be necessarily true and others to be possibly true now in order for us to discuss modality we need to include possible worlds possible worlds are what we use to discover the truth of modal propositions i.e what makes something necessarily true or possibly true for example take the statement two plus two equals four now this statement is a true statement right now but we need to ask ourselves can there be another world where logically this statement could not be true can we imagine such a place as this logically cannot be envisioned we can say the statement two plus two equals four is a necessary truth it is true in every possible world we can think of it is a logical necessity however consider the statement i could have been a dentist this is in fact a possible truth it is not true because i am not a dentist right now in this actual world and i know nothing of dentistry however we can imagine a possible world where i am a dentist there is no logical problem with this even though i am not a dentist this statement is a possible truth we can all imagine a world where i am a dentist possible worlds are therefore used all the time by philosophers to determine what are necessary or possible truths and to also look at how things could have been consider the plant in my garden that died i could say if that plant had more sunlight and water it would have survived what i'm really saying is in a possible world where that plant had more sunlight and water it would have lived longer or people can ponder what would england have looked like if william the conqueror didn't invade again we are thinking of a possible world where the states of affairs were different so a possible world is essentially the way the world could have been it is a device used to determine possible from necessary truths right so they are basically hypothetical thought experiments to help us discuss ways things could have been as well as discover the truths that are perpetual prime and facey they would appear so however when we dig a little deeper it doesn't actually seem that simple yes they are thought experiments but they are used as philosophical devices in determining truth we can liken them to a mathematician using an abacus the interesting thing is the abacus does actually exist we agree the abacus exists we also agree that numbers exist and sets exist and so on these are real they help us make sense of this actual world so it can be argued that possible worlds have some type of existence but what exactly is this existence how should we approach the ontological standing of possible worlds hmm interesting a fascinating theory emerged during the pondering of possible worlds known as modal realism put forward by the philosopher david lewis he argued that all possible worlds were in fact real concrete worlds that actually exist spatially and temporally every possible world every possible situation everything that could have been does actually exist in another world lewis explained when i profess realism about possible worlds i mean to be taken literally so right now there exists a world where i am a dentist or an astronaut or a rock star there exists a possible world where i don't exist or where you are a rock star there exists a world where the roman empire did not fall where humans never evolved where dinosaurs still roam where zeus and odin are best buddies there exists an infinite amount of worlds where every possible state of affairs that can or could exist does actually exist so you're saying right now it is true that i am say the king of england not true in this world lewis explained that this is the actual world and by actual he refers to this as just indexical just pointing to the world we currently live in however there is another world somewhere out there in the infinite where yes you are the king of england as this is not a logical impossibility it does not defy any logical laws it is technically possible for you to be the king of england and so there is a possible world where you are in fact the king of england wow so any chance i could actually visit this possible world actually no that is not possible lewis explains that each possible world exists in isolation you must understand possible worlds are the possibilities which do not obtain in your actual world and so you cannot have any experience of them there is no mingling or intertwining between possible worlds because as soon as you experience another possible world that becomes part of your actual world or let's say part of your actual reality and so it's no longer a possible world these possible worlds are completely outside of your reality they exist as islands it is not like parallel universes or dimensions with the possibility of interdimensional travel possible worlds are their own reality and cannot be experienced by anyone outside of that reality possible worlds are all isolated and there are no causal relations between the worlds i see lewis believed that possible worlds best explain modal metaphysics as mentioned philosophers have debated how we should view possible worlds but there is no denying that possible worlds exist we use them all the time we use them to think about what could have been we use them to discover counter factuals and how things may have gone if certain events or facts were different yes there is no question that they do exist but in what sense do they exist that is the debates that metaphysicians have been grappled with lewis here seems to have the best answer they exist as concrete real entities just as real as this actual world occam's razor can come into play here as this seems to be the simplest answer to the metaphysical question of modality right also consider that a possible truth can only be a possible truth if it's obtained in a possible world and so in order for the truth to obtain it needs a world to obtain in and thus that possible truth needs a possible world and that possible world needs to exist it needs to be real to be concrete so the truth can exist as a truth let us consider again counter factuals discussing what would have been if the circumstances were different people always agree that there are truths to how things could have been going back to my plant if it had more sunlight and water it would have lived longer so if there are truths to the way things could have been these truths need to exist somewhere the way it could have been needs to exist in another world there can be no sense or understanding of modality without accepting the existence of possible worlds as such we must lean on modal realism and approach every possible world everything that could have been every possible state of affairs that does not obtain in this world as existing in an infinite sea of spatially temporally isolated worlds truly fascinating theory and it's quite fun to think about i like the idea of me somewhere out there in the infinite being a famous rock star or an astronaut or a king it's quite cool to think about indeed however there are a number of criticisms of modal realism that i would like to discuss go for it so the first point is around trans world identity as you stated according to lewis's modal realism there is a possible world where i am an astronaut or a rock star or perhaps i'm six feet tall or i have different parents basically any possible event that could take place yes the problem is how could this still be considered me right now in this actual world i'm not a rock star if there is a possible world where i am i would probably think and act and talk and be very different so how is that still me if i was taller or smaller or have different parents how is this still me what is the fundamental that makes me me in all these possible worlds david lewis does address this with the counterpart theory rather than focusing on the metaphysics of identity lewis adopts the idea that each individual that exists in only one possible world will have counterparts existing in other possible worlds this counterpart is similar to you but does not have the essence of identity okay i'm not entirely sure what that means i understand that the metaphysics of identity can be a lengthy debate but this feels like a complete sidestep what exactly is a counterpart is it someone who just looks like me if someone shares my exact features but is different in every other way then i fail to see how they are my counterpart in another possible world could there also be a possible world where my counterpart has the exact same personality as me but looks completely different i suppose there could be a possible world where my counterpart has long hair or blue hair but if there is a possible world where my counterpart has different parents then i completely fail to see what makes them my counterparts i don't feel this is satisfactory and i don't see how i could exist in an infinite amount of possible worlds and still be considered me or my counterparts hmm furthermore one could use modal logic of necessary truths to prove that possible worlds do not exist how so well i could conceive of a possible world where no other possible worlds exist if this world is possible it would mean that no other worlds are possible and so all we are left with is just one possible world and since we live in a world that possible world has to be the actual world and so there are no more possible worlds i do not think that works as possible worlds can only exist if they are in fact possible it could be argued that a possible world where no other possible worlds exist is not a possibility especially since all possible worlds are spatially and temporarily isolated with no crossovers at all i do not see how no possible worlds can be a condition of any possible world as it cannot be part of any possible world i would say that that statement would be a logical impossibility and no such possible world could exist i think there is a debate here as i do not think there is any logical impossibility in the existence of a possible world that exists in an infinite all-encompassing total reality that does not have any other possible worlds i disagree i think a state of affairs of a possible world cannot affect another possible world as they are isolated so this possible world is impossible let's just leave that argument there very well moving on you mentioned occam's razor and that modal realism is actually the simplest solution to modal metaphysics yes i think that is incorrect in fact i see this as the most complicated messy theory there is really yes how so because this theory must account for an infinite amount of possibilities how is that a simple theory think about it there must be a possible world where i am five foot nine a possible world where i'm five foot eight a possible world around five foot seven and so on and so on a possible world where you was born on a tuesday one for wednesday one for the fifth of august one for the 12th of december one where i live at house 33 one where i live at house 34 one for house 55 etc etc every minute detail that doesn't exist needs a possible world where it does an infinite amount of possible worlds this sounds so hectic and so messy this in no way meets occam's razor criteria modal realism is the most overtly complex infinitely messy theory i see finally i would also like to mention that this theory has to deal with the incredulous stare what's that incredulous stare is a term taken from the confused look someone will give you when explaining this theory and that is because it goes against all common sense and intuition that people have honestly you have to convince someone that whatever could have existed does actually exist somewhere out there in the infinite try sitting someone down and explaining that it is possible that evolution took a different turn and rabbits developed the ability to talk and so there exists a world where rabbits are discussing modal realism and humans are hopping around in fields it sounds like a crazy nonsense theory it is not based on any empirical evidence and it actually would never even be able to be proven as we are by the very theory itself isolated from any contact with a possible world on top of that it doesn't really come with any rational or logical motivation to adopt such a theory other than it makes modal metaphysics easy which as i have argued i believe it also fails at that good point if you enjoy studying philosophy and you want to help support this channel then please make sure you check out the philosophy vibe 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Channel: Philosophy Vibe

Views: 11,513

Keywords: Philosophy, Vibe, possible worlds, possible worlds philosophy, possible worlds theory, moral realism, moral realism explained, modal realism philosophy, modal realism david lewis, david lewis philosophy, possible worlds theory philosophy, possible worlds david lewis, possible worlds david lewis philosophy, transworld identity, transworld identity philosophy, modeal realism possible worlds

Id: cxt_uMkdrhc

Length: 15min 12sec (912 seconds)

Published: Mon Jun 20 2022