Online research in philosophy

This paper concerns the semantics of belief-sentences. I pass over ontologically lavish theories which appeal to impossible worlds, or other points of reference which contain more than possible worlds. I then refute ontologically stingy, quotational theories. My own theory employs the techniques of possible worlds semantics to elaborate a Fregean analysis of belief-sentences. In a belief-sentence, the embedded clause does not have its usual reference, but refers rather to its own semantic structure. I show how this theory can accommodate quantification into belief-contexts. I close with skirmishes against the threat posed by the Liar Paradox.

According to an attractive account of belief, our beliefs have centered content. According to an attractive account of communication, we utter sentences to express our beliefs and share them with each other. However, the two accounts are in conflict. We have to either change our understanding of belief or modify our theory of communication. In this paper, I explore the consequences of holding on to the claim that beliefs have centered content. If we do in fact express the centered content of our beliefs, the content of the belief the hearer acquires cannot in general be identical to the content the speaker expresses. I sketch an alternative account of communication, the Recentering model, that accepts this consequence and explains how the expressed and the acquired content are related.

Some accounts of mental content represent the objects of belief as structured, using entities that formally resemble the sentences used to express and report attitudes in natural language; others adopt a relatively unstructured approach, typically using sets or functions. Currently popular variants of the latter include classical and neo-classical propositionalism, which represent belief contents as sets of possible worlds and sets of centered possible worlds, respectively; and property self-ascriptionism, which employs sets of possible individuals. I argue against their contemporary proponents that all three views are ineluctably plagued by generation gaps: they either overgenerate beliefs, undergenerate them, or both.

Indexical beliefs pose a special problem for standard theories of Bayesian updating. Sometimes we are uncertain about our location in time and space. How are we to update our beliefs in situations like these? In a stepwise fashion, I develop a constraint on the dynamics of indexical belief. As an application, the suggested constraint is brought to bear on the Sleeping Beauty problem.

David Lewis argues that centered worlds give us a way to capture de se, or self-locating, contents in philosophy of language and philosophy of mind. In recent years, centered worlds have also gained other uses in areas ranging widely from metaphysics to ethics. This paper raises a problem for centered worlds and discusses the costs and benefits of different solutions. The present investigation into the nature of centered worlds helps to explicate potentially problematic implicit commitments of the theories that employ them. In addition, this investigation reveals that the conception of centered worlds widely attributed to David Lewis is not only problematic, but in fact not his.

A widely accepted view in the discussion of personal identity is that the notion of psychological continuity expresses a one–many or many–one relation. This belief is unfounded. A notion of psychological continuity expresses a one–many or many–one relation only if it includes, as a constituent, psychological properties whose relation with their bearers is one–many or many–one; but the relation between an indexical psychological state and its bearer when first tokened is not a one–many or many–one relation. It follows that not all types of psychological continuity may take a one–many or many–one form. This conclusion casts doubt on the Lockean approach to the issue, by showing that the notion of psychological continuity Lockeans rely on may not be available.

Possible worlds semantics has been very useful in modeling not only the intensionality of necessity and possibility, future and past. It has also found its place in modeling the intentionality of propositional attitudes like belief and knowledge. There is something fruitful in analyzing a belief as a set of possible worlds. The belief is the set of possible worlds in which the belief is true. The belief is true if and only if the actual world is in the corresponding set of propositions. The possible worlds in the set corresponding to the belief represent how the agent per- ceives the world to be. If the belief is false, then the world isn’t how the agent sees the world to be, and so the actual world isn’t in the set of worlds corresponding to the belief (see Lewis [4] and Stalnaker [9]). The same can be said of whole belief states just as much as it can be said of individual beliefs. My belief state is the set of worlds consistent with what I believe. This view has been very fruitful, not least because the set-theoretic structure of sets of possible worlds corresponds nicely with the logical structure of entailment relations among propositions and the behavior of propositional connectives like conjunction, disjunction, and negation. However, the story does not deal well with inconsistent belief. Inconsistent beliefs are true in no possible worlds, so they are each modeled by the same set of worlds—the empty set. My beliefs are often inconsistent, and so are those of many..

Some time ago, John Perry argued that the content of an indexical belief, that is, a belief expressible with a sentence containing an indexical or demonstrative, cannot be a proposition. I consider several of his arguments for this view, and show that they can be extended to show that belief expressible with other non-indexical expressions such as natural kind terms and proper names presents the very same problem for the traditional picture. I then suggest that if indexical belief has any special status, this is not because it has a special kind of content, but rather because action is impossible if agents do not have indexical belief.

Belief and its benefits -- Belief, reason, goodness -- Belief and the unknown -- Obstacles to belief -- Belief and meaning -- Learning to believe -- Believing and living.