Table Of ContentThe Impossible
This page intentionally left blank
The Impossible
An Essay on Hyperintensionality
Mark Jago
1
3
GreatClarendonStreet,Oxford,ox26dp,
UnitedKingdom
OxfordUniversityPressisadepartmentoftheUniversityofOxford.
ItfurtherstheUniversity’sobjectiveofexcellenceinresearch,scholarship,
andeducationbypublishingworldwide.Oxfordisaregisteredtrademarkof
OxfordUniversityPressintheUKandincertainothercountries
©MarkJago2014
Themoralrightsoftheauthorhavebeenasserted
FirstEditionpublishedin2014
Impression:1
Allrightsreserved.Nopartofthispublicationmaybereproduced,storedin
aretrievalsystem,ortransmitted,inanyformorbyanymeans,withoutthe
priorpermissioninwritingofOxfordUniversityPress,orasexpresslypermitted
bylaw,bylicenceorundertermsagreedwiththeappropriatereprographics
rightsorganization.Enquiriesconcerningreproductionoutsidethescopeofthe
aboveshouldbesenttotheRightsDepartment,OxfordUniversityPress,atthe
addressabove
Youmustnotcirculatethisworkinanyotherform
andyoumustimposethissameconditiononanyacquirer
PublishedintheUnitedStatesofAmericabyOxfordUniversityPress
198MadisonAvenue,NewYork,NY10016,UnitedStatesofAmerica
BritishLibraryCataloguinginPublicationData
Dataavailable
LibraryofCongressControlNumber:2013956084
ISBN 978–0–19–870900–8
Asprintedandboundby
CPIGroup(UK)Ltd,Croydon,cr04yy
LinkstothirdpartywebsitesareprovidedbyOxfordingoodfaithand
forinformationonly.Oxforddisclaimsanyresponsibilityforthematerials
containedinanythirdpartywebsitereferencedinthiswork.
For Dad, with love
This page intentionally left blank
Contents
Acknowledgements viii
Introduction 1
1. ThePossibleWorldsApproach 21
2. Hyperintensionality 40
3. HyperintensionalityandStructure 71
4. ImpossibleWorlds 93
5. ConstructingWorlds 126
6. TheProblemofBoundedRationality 163
7. EpistemicSpace 193
8. EpistemicContent 227
Appendix:ModalEpistemicLogic 267
Bibliography 271
Index:Authors 288
Index:Terms 290
Acknowledgements
This book grew out of work on my Australian Research Council
DiscoveryProjectspostdoctoralgrantdp0880437,‘Rationalityand
Resource Bounds in Logics for Intentional Attitudes’, which ran
at Macquarie University, Sydney from July 2008 to January 2011.
Althoughthebookwaswrittenin2011and2012whilstlecturing
atNottingham,manyoftheideasinitdevelopedduringmystayat
Macquarie.HugethankstothedepartmentatMacquarieforhosting
mystayand,inparticular,toPeterMenziesforhistimeandadvice
asmypostdoctoralmentor.
DuringmystayatMacquarie,Ibenefittedgreatlyfrombeingapart
ofthemagnificentlysupportiveAustralianphilosophicalcommunity.
ThankstothephilosophersatSydneyUniversityformakingmefeel
veryathomeand,inparticular,toDavidBraddon-Mitchell,Mark
Colyvan,KristieMiller,NickSmithandHuwPricefortheirfriendship
and invaluable advice, both philosophical and gastronomic. I met
manywonderfulearlycareerresearchersinAustralia,withwhomI
discussedmanyoftheideasinthisbookandfromwhomIlearntso
much:JaminAsay,JensBjerring,RachaelBriggs,KennyEaswaran,
Alison Fernandes, Aidon Lyon, Dave Ripley, Wolfgang Schwarz,
LionelShapiro,MikeTitelbaumandAlistairWilson.I’msurethere
areotherswhoshouldbeinthislist:ifso,apologiesandthankyou
verymuch!
Manyoftheideasdiscussedherewerepresented,invariousstages
ofdevelopment,intalksatconferencesandworkshops:theHyper-
intensionality and Impossible Worlds workshop, ANU, Canberra,
22–23November,2008;UniversityofSydneyPhilosophyResearch
Seminar, 20 May 2009; Macquarie Philosophy Research Seminar,
28April2009;ANUresearchseminar,Canberra,28October2010;
PragueColloquiumonEpistemicAspectsofMany-ValuedLogics,
13–16 September, 2010; Philosophy of Information Workshop,
acknowledgements ix
UniversityofHertfordshire,10May2012;10thFormalEpistemology
Workshop, LMU Munich, 29 May–2 June 2012; Logica 2012,
Hejnice,CzechRepublic,18–22June2012;FoundationsofLogical
Consequenceconference,StAndrews,8–10June2012.
I’dliketothankalloftheaudiencesatthesetalks,whocontributed
valuablefeedbackonmyideas.Particulardebtsofgratitudeareowed
inthisregardtoRachaelBriggs,JensBjerring,DavidChalmers,David
Etlin,HannesLeitgeb,OleHjortland,PeterMenzies,GregRestall,
Graham Priest, Jonathan Schaffer, Sebastian Sequoiah-Grayson,
RobbieWilliamsandTimothyWilliamson.
Someoftheargumentsinthebookhaveappearedinpreviously
published articles. My discussion of the problem of information
in §2.2 draws on ‘Imagine the possibilities: Information without
overload’, Logique et Analyse 49 (2006), 345–71. The discussion
ofYagisawa’stheoryofworldsin§4.3follows‘AgainstYagisawa’s
modalrealism’,Analysis73(2013),10–17.Chapter5,onimpossible
worlds(inparticular,§5.2,§5.3,§5.5and§5.6),drawson‘Impossible
worlds’, forthcoming in Noûs. An earlier version of an argument
in §5.3 appeared in ‘Constructing worlds’, Synthese 189 (2012),
59–74. The material on negative facts in §5.4 was worked out
jointlywithStephenBarker,andappearedinourjoint‘Beingpositive
aboutnegativefacts’,PhilosophyandPhenomenologicalResearch
85(2012),117–38.
Thenegativepartsofchapter6,inwhichIargueagainstvarious
responsestothelogicalomniscienceproblem(§6.2and§6.3),draw
on ‘Hintikka and Cresswell on logical omniscience’, Logic and
LogicalPhilosophy15(2007),325–54.Thediscussionofvagueness
thatfollows,§6.4,drawson‘Theproblemofrationalknowledge’,
forthcoming in Erkenntnis. The ideas behind my construction of
epistemicspacein§7.1and§7.2firstappearedindevelopedform
in‘Logicalinformationandepistemicspace’,Synthese167(2009),
327–41;amuchearlierformoftheideawaspresentedin‘Imagine
thepossibilities:Informationwithoutoverload’,LogiqueetAnalyse
49(2006),345–71.
Myaccountofthecontentofinformativelogicaldeductionsin§8.2
Description:Mark Jago presents an original philosophical account of meaningful thought: in particular, how it is meaningful to think about things that are impossible. We think about impossible things all the time. We can think about alchemists trying to turn base metal to gold, and about unfortunate mathematici
