Online research in philosophy

Traditionally, Anglophone philosophers have assumed that the identity of a thought is determined wholly by the subject's intrinsic states--e.g., her brain states. In the 1970's, this traditional view (lately called 'individualism' or ‘internalism’) was challenged by Hilary Putnam and Tyler Burge, who argued that the contents of one’s beliefs, desires, intentions are partly determined by one's physical, social and/or linguistic environment. The question is not whether the environment causes one to think what one does. Rather, the question is one of the identity of thoughts: In virtue of what is a thought the particular thought that it is? According to Putnam and Burge, the answer lies partly in the environment. What makes the belief expressed by ‘water is wet’ the belief that it is depends on the presence of H2O in the environment, not just on the believer’s internal states. The view that thoughts are individuated in part by environmental factors has come to be called ‘anti-individualism’ or ‘externalism’.

Abstract Stephen P. Stich rejects the de dicto?de re belief state and ascription distinction. He proposes an analysis by which belief sentences imply univocal doxastic predicates expressing functionally similar states of belief subjects and counterfactual third person belief ascribers, concluding that the apparent opacity of de dicto belief sentences is better explained by the unsystematic contextually?sensitive similarity vaguenesses of belief ascriptions. But Stick's reduction appeals to contexts of background beliefs which themselves unavoidably exhibit ramified de dicto?de re ambiguity. The distinction is presupposed rather than eliminated by Stick's method, which effectively blocks the extensional reduction of belief state opacity.

The main ingredients of Spohn's theory of epistemic beliefs are (1) a functional representation of an epistemic state called a disbelief function and (2) a rule for revising this function in light of new information. The main contribution of this paper is as follows. First, we provide a new axiomatic definition of an epistemic state and study some of its properties. Second, we study some properties of an alternative functional representation of an epistemic state called a Spohnian belief function. Third, we state a rule for combining disbelief functions that is mathematically equivalent to Spohn's belief revision rule. Whereas Spohn's rule is defined in terms of the initial epistemic state and some features of the final epistemic state, the rule of combination is defined in terms of the initial epistemic state and the incremental epistemic state representing the information gained. Fourth, we state a rule of subtraction that allows one to recover the addendum epistemic state from the initial and final epistemic states. Fifth, we study some properties of our rule of combination. One distinct advantage of our rule of combination is that besides belief revision, it can be used to describe an initial epistemic state for many variables when this information is given as several independent epistemic states each involving few variables. Another advantage of our reformulation is that we can show that Spohn's theory of epistemic beliefs shares the essential abstract features of probability theory and the Dempster-Shafer theory of belief functions. One implication of this is that we have a ready-made algorithm for propagating disbelief functions using only local computation.

If the logic of belief changes is extended to cover belief states which contain both factual and normative beliefs, it is easily shown that a change of a factual belief (an 'Is') in a mixed belief state can imply a change of a normative belief (an 'Ought') in the same state. With regard to Hume's so-called 'Is-Ought problem', this means that one has to distinguish its statics from its dynamics. When this is done, it becomes clear that changes of factual beliefs can, for rational reasons, have far-reaching normative consequences. Similarly, a change of a factual belief can imply a change of a value belief.

Hume's claim that a state is a belief is often intertwined-though without his remarking on this fact-with epistemic approval of the state. This requires explanation. Beliefs, in Hume's view, are steady dispositions (not lively ideas), nature's provision for a steady influence on the will and action. Hume's epistemic distinctions call attention to circumstances in which the presence of conflicting beliefs undermine a belief's influence and thereby its natural function. On one version of this interpretation, to say that a belief is justified, ceteris paribus, is to say that for all that has been shown the belief would be steady in its influence under suitable reflection. On a second version, it is to say that prima facie justification is an intrinsic property of the state, in virtue of its steadiness. These versions generate different understandings of the relationship between Parts iii and iv of Book I of the Treatise.

The word 'belief' is ambiguous, referring sometimes to what is believed, sometimes to the act or state of believing it. I believe that as I write this it is sunny outside. This belief is true. What is true is what I believe, namely that it is sunny, not my believing it. On the other hand, my belief that it is sunny is rational and unshakeable, and it played a causal role in my deciding not to wear a coat today. What is rational, unshakeable, and played a causal role is my believing a certain thing, not the thing I believe. I will say that what I believe is an object of belief , and that my believing it is a belief state.

Does the strength with which we hold a particular belief depend upon the significance we attach to it? Might we move from one context to another, remaining in the same doxastic state concerning p, yet holding a stronger belief that p in one context than we do in the other? In order for that to happen, a doxastic state, a belief state, must have a certain sort of complexity, a context-sensitivity that yields, in the presence of one set of stakes, a belief of one strength, and in the presence of different stakes, a belief of a different strength. So the question is about the nature of belief states, as we understand them, or as we think a theory should model them. I explore the idea that beliefs might have stake-sensitive complexity, and how it relates to work on imprecise probabilities and second-order confidence.

The principle of belief persistence, or conservativity principle, states that ’\Nhen changing beliefs in response to new evidence, you should continue to believe as many of the old beliefs as possible' (Harman, 1986, p. 46). In particular, this means that if an individual gets new information, she has to accommodate it in her new belief set (the set of propositions she believes), and, if the new information is not inconsistent with the old belief set, then (1) the individual has to maintain all the beliefs she previously had and (2) the change should be minimal in the sense that every proposition in the new belief set must be deducible from the union of the old belief set and the new information (see, e.g., Gardenfors, 1988; Stalnaker, 1984). We focus on this minimal notion of belief persistence and characterize it both semantically and syntactically. A ’possible world' semantic formalization of the principle easily comes to mind. The set of all the propositions that the individual believes corresponds to the set of states of the world that she considers possible and is a subset of the set of states that are not ruled out by the individual's information (or knowledge). It is required that, if the individual considers a state possible and her new information does not exclude this state, then she continue to consider it possible. Furthermore, if the individual regards a particular state as impossible, then she should continue to regard it as impossible unless her new information excludes all the states that she previously regarded as possible. This is closely related to the..

The first thesis is that beliefs play a role in explaining behavior. This is reasonably uncontroversial, though it has been controverted. Why did I raise my arm? Because I wanted to emphasize a point, and believed that I could do so by raising my arm. The belief that I could emphasize a point by raising my arm is central to the most natural explanation of my action.