Editing World (section)

=== Theories of modality ===
The world-concept plays a role in many modern theories of modality, sometimes in the form of [[possible worlds]].<ref>{{cite web |last1=Parent |first1=Ted |title=Modal Metaphysics |url=https://iep.utm.edu/mod-meta/ |website=Internet Encyclopedia of Philosophy |access-date=9 April 2021}}</ref> A possible world is a complete and consistent way how things could have been.<ref name="Menzel">{{cite web |last1=Menzel |first1=Christopher |title=Possible Worlds |url=https://plato.stanford.edu/entries/possible-worlds/ |website=The Stanford Encyclopedia of Philosophy |publisher=Metaphysics Research Lab, Stanford University |access-date=9 April 2021 |date=2017}}</ref> The actual world is a possible world since the way things are is a way things could have been. There are many other ways things could have been besides how they actually are. For example, Hillary Clinton did not win the 2016 US election, but she could have won them. So there is a possible world in which she did. There is a vast number of possible worlds, one corresponding to each such difference, no matter how small or big, as long as no outright contradictions are introduced this way.<ref name="Menzel"/>

Possible worlds are often conceived as abstract objects, for example, in terms of non-obtaining [[states of affairs]] or as maximally consistent sets of propositions.<ref>{{cite journal |last1=Jacquette |first1=Dale |title=Propositions, Sets, and Worlds |journal=Studia Logica |date=1 April 2006 |volume=82 |issue=3 |pages=337–343 |doi=10.1007/s11225-006-8101-2 |s2cid=38345726 |url=https://link.springer.com/article/10.1007/s11225-006-8101-2 |language=en |issn=1572-8730}}</ref><ref>{{cite web |last1=Menzel |first1=Christopher |title=Possible Worlds > Problems with Abstractionism |url=https://plato.stanford.edu/entries/possible-worlds/problems-abstractionism.html |website=Stanford Encyclopedia of Philosophy |access-date=9 April 2021}}</ref> On such a view, they can even be seen as belonging to the actual world.<ref>{{cite web |last1=Menzel |first1=Christopher |title=Actualism > An Account of Abstract Possible Worlds |url=https://plato.stanford.edu/entries/actualism/possible-worlds.html |website=Stanford Encyclopedia of Philosophy |access-date=9 April 2021}}</ref> Another way to conceive possible worlds, made famous by [[David Lewis (philosopher)|David Lewis]], is as concrete entities.<ref name="Lewis"/> On this conception, there is no important difference between the actual world and possible worlds: both are conceived as concrete, inclusive and spatiotemporally connected.<ref name="Menzel"/> The only difference is that the actual world is the world ''we'' live in, while other possible worlds are not inhabited by us but by our ''counterparts''.<ref name="Bricker">{{cite journal |last1=Bricker |first1=Phillip |title=David Lewis: On the Plurality of Worlds |journal=Central Works of Philosophy, Vol. 5: The Twentieth Century: Quine and After |date=2006 |pages=246–267 |url=https://philpapers.org/rec/BRIDLO |publisher=Acumen Publishing|doi=10.1017/UPO9781844653621.014 |isbn=9781844653621 }}</ref> Everything within a world is spatiotemporally connected to everything else but the different worlds do not share a common spacetime: They are spatiotemporally isolated from each other.<ref name="Menzel"/> This is what makes them separate worlds.<ref name="Bricker"/>

It has been suggested that, besides possible worlds, there are also impossible worlds. Possible worlds are ''ways things could have been'', so impossible worlds are ''ways things could not have been''.<ref name="Berto">{{cite web |last1=Berto |first1=Francesco |last2=Jago |first2=Mark |title=Impossible Worlds |url=https://plato.stanford.edu/entries/impossible-worlds/ |website=The Stanford Encyclopedia of Philosophy |publisher=Metaphysics Research Lab, Stanford University |date=2018}}</ref><ref>{{cite journal |last1=Zalta |first1=Edward N. |title=A Classically-Based Theory of Impossible Worlds |journal=Notre Dame Journal of Formal Logic |date=1997 |volume=38 |issue=4 |pages=640–660 |doi=10.1305/ndjfl/1039540774 |url=https://philpapers.org/rec/ZALACT|doi-access=free }}</ref> Such worlds involve a contradiction, like a world in which Hillary Clinton both won and lost the 2016 US election. Both possible and impossible worlds have in common the idea that they are totalities of their constituents.<ref name="Berto"/><ref>{{cite book |last1=Ryan |first1=Marie-Laure |title=Immersion and Distance |date=2013 |publisher=Brill Rodopi |isbn=978-94-012-0924-3 |url=https://brill.com/view/book/edcoll/9789401209243/B9789401209243-s006.xml |language=en |chapter=Impossible Worlds and Aesthetic Illusion}}</ref>