Dissertation, Australian National University (2010)

Authors
Abstract
In a possible world framework, an agent can be said to know a proposition just in case the proposition is true at all worlds that are epistemically possible for the agent. Roughly, a world is epistemically possible for an agent just in case the world is not ruled out by anything the agent knows. If a proposition is true at some epistemically possible world for an agent, the proposition is epistemically possible for the agent. If a proposition is true at all epistemically possible worlds for an agent, the proposition is epistemically necessary for the agent, and as such, the agent knows the proposition. This framework presupposes an underlying space of worlds that we can call epistemic space. Traditionally, worlds in epistemic space are identified with possible worlds, where possible worlds are the kinds of entities that at least verify all logical truths. If so, given that epistemic space consists solely of possible worlds, it follows that any world that may remain epistemically possible for an agent verifies all logical truths. As a result, all logical truths are epistemically necessary for any agent, and the corresponding framework only allows us to model logically omniscient agents. This is a well-known consequence of the standard possible world framework, and it is generally taken to imply that the framework cannot be used to model non-ideal agents that fall short of logical omniscience. A familiar attempt to model non-ideal agents within a broadly world involving framework centers around the use of impossible worlds where the truths of logic can be false. As we shall see, if we admit impossible worlds where “anything goes” in epistemic space, it is easy to avoid logical omniscience. If any logical falsehood is true at some impossible world, then any logical falsehood may remain epistemically possible for some agent. As a result, we can use an impossible world involving framework to model extremely non-ideal agents that do not know any logical truths. A much harder, and considerably less investigated challenge is to ensure that the resulting epistemic space can also be used to model moderately ideal agents that are not logically omniscient but nevertheless logically competent. Intuitively, while such agents may fail to rule out impossible worlds that verify complex logical falsehoods, they are nevertheless able to rule out impossible worlds that verify obvious logical falsehoods. To model such agents, we need a construction of a non-trivial epistemic space that partly consists of impossible worlds where not "anything goes". This involves imposing substantive constraints on impossible worlds to eliminate from epistemic space, say, trivially impossible worlds that verify obvious logical falsehoods. The central aim of this dissertation is to investigate the nature of such non-trivially impossible worlds and the corresponding epistemic spaces. To flag my conclusions, I argue that successful constructions of epistemic spaces that can safely navigate between the Charybdis of logical omniscience and the Scylla of of “anything goes” are hard, if not impossible to find.
Keywords No keywords specified (fix it)
Categories (categorize this paper)
Options
Edit this record
Mark as duplicate
Export citation
Find it on Scholar
Request removal from index
Translate to english
Revision history

Download options

PhilArchive copy

 PhilArchive page | Other versions
External links

Setup an account with your affiliations in order to access resources via your University's proxy server
Configure custom proxy (use this if your affiliation does not provide a proxy)
Through your library

References found in this work BETA

No references found.

Add more references

Citations of this work BETA

The Nature of Epistemic Space.David J. Chalmers - 2011 - In Andy Egan & Brian Weatherson (eds.), Epistemic Modality. Oxford University Press.
Impossible Worlds.Franz Berto & Mark Jago - 2013 - Oxford: Oxford University Press.

View all 7 citations / Add more citations

Similar books and articles

Logical Information and Epistemic Space.Mark Jago - 2009 - Synthese 167 (2):327 - 341.
Systems of Modal Logic for Impossible Worlds.Charles G. Morgan - 1973 - Inquiry: An Interdisciplinary Journal of Philosophy 16 (1-4):280 – 289.
Imagine the Possibilities: Information Without Overload.Mark Jago - 2006 - Logique Et Analyse 49 (196):345–371.
Counterpossibles.Barak Krakauer - 2012 - Dissertation, University of Massachusetts
Hintikka and Cresswell on Logical Omniscience.Mark Jago - 2006 - Logic and Logical Philosophy 15 (3):325-354.
Epistemic Logic for Rule-Based Agents.Mark Jago - 2009 - Journal of Logic, Language and Information 18 (1):131-158.
Epistemically Relevant Possible Worlds.Winfried Löffler - 2002 - Grazer Philosophische Studien 63 (1):287-301.
A Classically-Based Theory of Impossible Worlds.Edward N. Zalta - 1997 - Notre Dame Journal of Formal Logic 38 (4):640-660.
Ways Things Can't Be.Greg Restall - 1997 - Notre Dame Journal of Formal Logic 38 (4):583-596.
Real Impossible Worlds : The Bounds of Possibility.Ira Georgia Kiourti - 2010 - Dissertation, University of St Andrews
对象、可能世界与必然性 —《逻辑哲学论》的本体论分析.Daqiang Li - 2008 - Proceedings of the Xxii World Congress of Philosophy 39:319-333.

Analytics

Added to PP index
2011-04-02

Total views
758 ( #6,608 of 2,410,719 )

Recent downloads (6 months)
62 ( #11,591 of 2,410,719 )

How can I increase my downloads?

Downloads

My notes