Definite Descriptions in a 2-D Semantics for Epistemic Modals
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DEFINITE DESCRIPTIONS IN A 2-D SEMANTICS FOR EPISTEMIC MODALS A thesis submitted to the faculty of / San Francisco State University 2 ,f. In partial fulfillment of The Requirements for The Degree Master of Arts In Philosophy by Patrick Daniel Skeels San Francisco, California May 2016 Copyright by Patrick Daniel Skeels ©2016 CERTIFICATION OF APPROVAL I certify that I have read Definite Descriptions in a 2-D Semantics for Epistemic Modals by Patrick Daniel Skeels, and that in my opinion this work meets the criteria for approving a thesis submitted in partial fulfillment of the requirements for the degree: Master of Arts in Phi losophy at San Francisco State University Dr. Carlos Montemayor Associate Professor of Philosophy Dr. Bas C. van Fraassen Professor of Philosophy DEFINITE DESCRIPTIONS IN A 2-D SEMANTICS FOR EPISTEMIC MODALS Patrick Daniel Skeels San Francisco State University 2016 In the following, I begin with some puzzles of epistemic modality, after which I present a 2-Dimensional semantics developed by Holliday that aims to solve them. I then detail how Holliday's semantics interacts with both the Russellian and the Fregean theories of definite descriptions. I conclude that it is compatible with both. I certify that the Abstract is a correct representation of the content of this thesis. Chair, Thesis Committee Date TABLE OF CONTENTS List of Appendices ....................................................................................................... vi Introduction................................................................................................................... 1 1 A Few Puzzles of Epistemic Modality ............................................................... 4 2 A Two-Dimensional Solution ............................................................................. 6 2.1 Informal Introduction................................................................................... 6 2.2 Holliday 2015 ................................................................................................ 8 2.3 Applications................................................................................................... 11 3 Definite D escriptions............................................................................................. 13 3.1 Russellian Theory of Definite Descriptions.............................................. 14 3.2 Fregean Theory of Definite Descriptions................................................. 17 4 Concluding Remarks...................................................... 24 5 Appendix...................................................................................................................... 26 6 Works C it e d ............................................. 34 v List of Appendices A.l .......................................................................................................................................26 A.2 .......................................................................................................................................26 A.3 .......................................................................................................................................27 A.4: Expanded Truth Conditions for .........................................................................28 A.5 .......................................................................................................................................28 A.6 .......................................................................................................................................29 A.7 .......................................................................................................................................30 A.8: Equivalence of <3 and 9 R ........................................................................................ 31 A.9 .......................................................................................................................................32 A .1 0 .......................................................................................................................................32 A . l l .......................................................................................................................................33 vi 1 Introduction Imagine that we are chatting as we walk past a schoolyard. We notice that some children are about to have a footrace. The mood is playful, yet competitive, and our attention is momentarily pried from our usual philosophical discussion to some thing more visceral. The race begins. It's a close one. But in the end, as you may have guessed, the winner won. After the race unfolds, I utter: (1) The winner of the race could have lost. You agree. After all, the race was close, and it wasn't a forgone conclusion that that child was to be the winner. The most natural reading of "could" in this context classifies it as a metaphysical modal. This means that there is a possible world, metaphysically accessible from our own, where that very child didn't win. This is easy enough to imagine. Kripke semantics gives (1) the following truth conditions: (IT) The person x, who was the winner of the race in zv is such that there is some world w' metaphysically accessible from zv such that x is not the winner of the race. (IT) is perfectly coherent, as we'd expect. Kripke taught us that an object can have nontrivial modal properties independent from its means of individuation ([3] pp 63-67). All in all, a sentence like (1) is perfectly fine, according to both our semantics and our ears. 2 Now suppose that the conversation went just a little differently. The scenario plays out exactly the same as before, but instead of uttering (1 ), I utter: (2) #The winner of the race might have lost. Rather than agreement, I'm met with a perplexed look. Something about this sen tence isn't quite right. Unlike "could", "might" is most naturally read as an epis- temic modal. An epistemic modal allows for possibility and necessity, but only relative to an information state. An information state is a set of possible worlds, each of which is seen as a candidate for the real world. As an agent comes to be lieve a proposition, she eliminates worlds from the information state where that proposition is not true ([6] pp 86-87). Recall that we came to believe that a particu lar individual won, which means that we've eliminated all worlds where that same individual didn't win from our information state. But this means that an utterance of (2) says that the very worlds that have been eliminated are somehow still candi dates for the real world. Understood this way, (2) doesn't just sound strange. It is contradictory. We expect this to be apparent in the truth conditions: (2T) The person x, who was the winner of the race in w is such that there is some world w' in information state I that is epistemically accessible from w such that x is not the winner of the race. Interestingly, (2T) is satisfiable, despite the contradiction! A state of ignorance regarding the race result would include both w and w' and would satisfy (2T), but 3 (2) is contradictory, and should not have satisfiable truth conditions. Something is wrong. We find ourselves in a predicament. An utterance of (2) is infelicitous because it is contradictory to individuate an object with a property while simultaneously entertaining that it does not have that property. Nonetheless, (2) has perfectly sat isfiable truth-conditions. The problem generalizes. It appears that the epistemic modal properties of an object must be dependent on the way the object is indi viduated, if the sentence containing the modal is to be felicitous ([8] pp 475-477). Returning to (2), the information state can only include worlds where the winner in w won, since we've individuated this child as "the winner". Standard possible world semantics does not account for this unique behavior. We need a semantics that does. In the following, we'll take a look at a brand new two-dimensional semantics that predicts the behavior of epistemic modals. The semantics, which we'll call Holliday 2015, is a work in progress, and presently lacks a theory of definite de scriptions. The technical aim of the paper is to provide Holliday 2015 with a theory of definite descriptions which allows it to make the proper predictions. There are many theories fit for candidacy, the two most prevalent of which are the familiar Fregean and Russellian theories. We shall outfit the system with each and observe the formal results. As we shall see, both theories are compatible. The philosoph ical implications of these results are of no small consequence, as other semantics 4 designed to predict the behavior of epistemic modals, most notably Yalcin 2015, are not compatible with the Fregean theory of definite descriptions ([11] pp 7-8). As such, the broader, more philosophical goal of the paper will be to see what the newer problem of epistemic modals has to say about the much older problem of definite descriptions. More narrowly, I'll argue that with the introduction of Hol liday 2015, the Fregean is, in fact, capable of predicting the behavior of epistemic modals. 1 A Few Puzzles of Epistemic Modality1 We began with a puzzling asymmetry between (1 ) and (2). The problem is not limited to epistemic modals bound by definite descriptions. We notice further asymmetries with indefinites. The following universally or existentially quanti fied sentences are reported as infelicitous: (3) #Some person who is not infected, might