Two Ways to Want?

I present unexplored and unaccounted for uses of 'wants'. I call them advisory uses, on which information inaccessible to the desirer herself helps determine what she wants. I show that extant theories by Stalnaker, Heim, and Levinson fail to predict these uses. They also fail to predict true indicative conditionals with 'wants' in the consequent. These problems are related: intuitively valid reasoning with modus ponens on the basis of the conditionals in question results in unembedded advisory uses. I consider two fixes, and end up endorsing a relativist semantics, according to which desire attributions express information-neutral propositions. On this view, 'wants' functions as a precisification of 'ought', which exhibits similar unembedded and compositional behavior. I conclude by sketching a pragmatic account of the purpose of desire attributions that explains why it made sense for them to evolve in this way

Logics of Imprecise Comparative Probability

This paper studies connections between two alternatives to the standard probability calculus for representing and reasoning about uncertainty: imprecise probability andcomparative probability. The goal is to identify complete logics for reasoning about uncertainty in a comparative probabilistic language whose semantics is given in terms of imprecise probability. Comparative probability operators are interpreted as quantifying over a set of probability measures. Modal and dynamic operators are added for reasoning about epistemic possibility and updating sets of probability measures

Paradox in Thought and Natural Language

Around 600BC, Epimenides, a Cretan apparently discontented with thehonesty of his compatriots, lamented that all Cretans are liars.Together with a few innocent assumptions, well-entrenched principlesof logic entail that Epimenides' lamentation cannot be true, and yetcannot be untrue---a flat contradiction. What's gone wrong? In thisdissertation, I argue that the source of the problem has beenmisdiagnosed as one about language (especially formal languages). Theproblem runs deeper, and stems from the structure of thought itself. The dissertation proceeds in two main stages. The first stage(Chapter 2) makes the case that that the intuitions that underlie theparadoxes come from natural languages, not from formal/mathematicalones. The Liar and related paradoxes are generally presented asconstraints on the latter. Their lesson, the story goes, is that noformal theory strong enough to represent the primitive recursivefunctions can include a satisfactory truth predicate. I argue thatit's our natural-language competence with the truth predicate thatunderlies our understanding of what 'satisfactory' means here, whichshifts the focus of the project to natural language semantics. In thisdomain, it's tempting to think (and many have thought) that theproblem with Epimenides' utterance is that it fails to express aproposition, and this failure explains why we have trouble assigningit a truth-value. Or, perhaps it does express a proposition, but notthe one that it seems to express. Or, perhaps it can express aproposition, but which proposition it expresses depends on context. Iargue that all such responses fail, in part because they cannot makesense of related attitude attributions. I can believe or disbelieveEpimenides, which wouldn't be possible if his utterance didn't expressthe proposition it seems to express.In the second stage, I argue that such paradoxes arise, not from thelanguage/thought interface, but rather from thought itself. The firststep in this argument concerns knowledge attributions (Chapter 3),where I develop and defend a novel solution to the Knower paradox.Then I move from attitude attributions to attitudes themselves(Chapter 4). Just as sentential truth and knowledge predicates givesrise to paradoxical sentences, seemingly innocent combinations ofbeliefs and desires give rise to paradoxical propositions---even whenthose beliefs and desires are not expressed in language. Thepossibility of such pathological combinations isn't accounted for byany extant theory of mental content, and, I argue, provides supportfor a non-classical theory. Finally (Chapter 5) I consider anobjection to these putative combinations of desires. I introduce whatI call /advisory/ desire reports, which seem to exhibit the radicallyexternalist behavior that the previous chapter rejects. I conclude byoffering reasons to think that the availability of these readings doesnot undermine the case for non-classical accounts of attitudes

Preferential Structures for Comparative Probabilistic Reasoning

Qualitative and quantitative approaches to reasoning about uncertainty can lead to different logical systems for formalizing such reasoning, even when the language for expressing uncertainty is the same. In the case of reasoning about relative likelihood, with statements of the form φ ≥ ψ expressing that φ is at least as likely as ψ, a standard qualitative approach using preordered preferential structures yields a dramatically different logical system than a quantitative ap- proach using probability measures. In fact, the standard pref- erential approach validates principles of reasoning that are incorrect from a probabilistic point of view. However, in this paper we show that a natural modification of the preferential approach yields exactly the same logical system as a probabilistic approach—not using single probability measures, but rather sets of probability measures. Thus, the same preferential structures used in the study of non-monotonic logics and belief revision may be used in the study of comparative probabilistic reasoning based on imprecise probabilities

Preferential Structures for Comparative Probabilistic Reasoning

Qualitative and quantitative approaches to reasoning about uncertainty can lead to different logical systems for formalizing such reasoning, even when the language for expressing uncertainty is the same. In the case of reasoning about relative likelihood, with statements of the form φ

Preferential Structures for Comparative Probabilistic Reasoning

Qualitative and quantitative approaches to reasoning about uncertainty can lead to different logical systems for formalizing such reasoning, even when the language for expressing uncertainty is the same. In the case of reasoning about relative likelihood, with statements of the form φ ≥ ψ expressing that φ is at least as likely as ψ, a standard qualitative approach using preordered preferential structures yields a dramatically different logical system than a quantitative ap- proach using probability measures. In fact, the standard pref- erential approach validates principles of reasoning that are incorrect from a probabilistic point of view. However, in this paper we show that a natural modification of the preferential approach yields exactly the same logical system as a probabilistic approach—not using single probability measures, but rather sets of probability measures. Thus, the same preferential structures used in the study of non-monotonic logics and belief revision may be used in the study of comparative probabilistic reasoning based on imprecise probabilities