The main thesis of this paper is that it is not possible to determine the nature of epistemic justification apart from scientific psychological investigation. I call this view the strong thesis of methodological psychologism. Two sub-theses provide the primary support for this claim. The first sub-thesis is that no account of epistemic justification is correct which requires for the possession of at least one justified belief a psychological capacity which humans do not have. That is, the correct account of epistemic (...) justification must be psychologically realistic. The second sub-thesis is that it is not possible to determine whether an account of epistemic justification is psychologically realistic apart from scientific psychological investigation. After defending these subtheses, I point out some interesting consequences of the overall thesis which present a challenge to traditional epistemology. (shrink)

Belief storage is often modeled as having the structure of a single, unified web. This model of belief storage is attractive and widely assumed because it appears to provide an explanation of the flexibility of cognition and the complicated dynamics of belief revision. However, when one scrutinizes human cognition, one finds strong evidence against a unified web of belief and for a fragmented model of belief storage. Using the best available evidence from cognitive science, we develop this fragmented model into (...) a nascent theory of the cognitive architecture of belief storage. (shrink)

Bayesian confirmation theory is our best formal framework for describing inductive reasoning. The problem of old evidence is a particularly difficult one for confirmation theory, because it suggests that this framework fails to account for central and important cases of inductive reasoning and scientific inference. I show that we can appeal to the fragmentation of doxastic states to solve this problem for confirmation theory. This fragmentation solution is independently well-motivated because of the success of fragmentation in solving other problems. I (...) also argue that the fragmentation solution is preferable to other solutions to the problem of old evidence. These other solutions are already committed to something like fragmentation, but suffer from difficulties due to their additional commitments. If these arguments are successful, Bayesian confirmation theory is saved from the problem of old evidence, and the argument for fragmentation is bolstered by its ability to solve yet another problem. (shrink)

It would be good to have a Bayesian decision theory that assesses our decisions and thinking according to everyday standards of rationality — standards that do not require logical omniscience (Garber 1983, Hacking 1967). To that end we develop a “fragmented” decision theory in which a single state of mind is represented by a family of credence functions, each associated with a distinct choice condition (Lewis 1982, Stalnaker 1984). The theory imposes a local coherence assumption guaranteeing that as an agent's (...) attention shifts, successive batches of "obvious" logical information become available to her. A rule of expected utility maximization can then be applied to the decision of what to attend to next during a train of thought. On the resulting theory, rationality requires ordinary agents to be logically competent and to often engage in trains of thought that increase the unification of their states of mind. But rationality does not require ordinary agents to be logically omniscient. (shrink)

The extended mind thesis claims that some mental states and cognitive processes extend onto the environment. Items external to the organism or exploratory actions may constitute in part mental states and cognitive processes. In Clark and Chalmers’ original paper, ‘The Extended Mind’, this thesis receives support from the parity principle and from the active externalism. In their paper, more emphasis is given to the parity principle, which is presented as neutral regarding the nature of cognition. It would be advantageous to (...) maintain that extended mental states and processes do not require a reform of our pre-theoretical view of cognition. In the present paper, I submit that we should give more emphasis on the active externalism, which, I argue, is not neutral regarding the nature of cognition. Cognition is viewed as successful adaptation to a specific task. Although this move may seem at first disadvantageous, it is necessary for the correct understanding and justification of Otto case as an example of extended mental state. Additionally, the parity principle cannot handle Weiskopf’s criticism that information registered in Otto’s notebook is not responsive to reasons. In order to address this criticism, we need to appeal to active externalism and its corresponding view of cognition. (shrink)

Bayesian Epistemology is a general framework for thinking about agents who have beliefs that come in degrees. Theories in this framework give accounts of rational belief and rational belief change, which share two key features: (i) rational belief states are represented with probability functions, and (ii) rational belief change results from the acquisition of evidence. This dissertation focuses specifically on the second feature. I pose the Evidence Question: What is it to have evidence? Before addressing this question we must have (...) an understanding of Bayesian Epistemology. The first chapter argues that we should understand Bayesian Epistemology as giving us theories that are evaluative and not action-guiding. I reach this verdict after considering the popular ‘ought’-implies-‘can’ objection to Bayesian Epistemology. The second chapter argues that it is important for theories in Bayesian Epistemology to answer the Evidence Question, and distinguishes between internalist and externalist answers. The third and fourth chapters present and defend a specific answer to the Evidence Question. The account is inspired by reliabilist accounts of justification, and attempts to understand what it is to have evidence by appealing solely to considerations of reliability. Chapter 3 explains how to understand reliability, and how the account fits with Bayesian Epistemology, in particular, the requirement that an agent’s evidence receive probability 1. Chapter 4 responds to objections, which maintain that the account gives the wrong verdict in a variety of situations including skeptical scenarios, lottery cases, scientific cases, and cases involving inference. After slight modifications, I argue that my account has the resources to answer the objections. The fifth chapter considers the possibility of losing evidence. I show how my account can model these cases. To do so, however, we require a modification to Conditionalization, the orthodox principle governing belief change. I present such a modification. The sixth and seventh chapters propose a new understanding of Dutch Book Arguments, historically important arguments for Bayesian principles. The proposal shows that the Dutch Book Arguments for implausible principles are defective, while the ones for plausible principles are not. The final chapter is a conclusion. (shrink)

This paper explores the sense in which rational requirements govern our attitudes like belief and intention. I argue that there is a tension between the idea that rational requirements govern attitudes understood as standing states and the attractive idea that we can directly satisfy the requirements by performing reasoning. I identify the tension by (a) illustrating how a dispositional conception of belief can cause trouble for the idea that we can directly revise our attitudes through reasoning by considering John Broome's (...) view, and (b) advancing a general argument that a standing state cannot be directly affected by reasoning. I then propose a solution: by recognizing the proper targets of rational requirements as occurrent, rather than dispositional attitudes, we can preserve the idea that we can directly satisfy rational requirements through reasoning. (shrink)

For epistemic subjects like us, updating our credences incurs epistemic costs. Expending our limited processing power and working memory to properly update our credences by some information can come at the cost of not responding to other available information. It is thus desirable to flesh out and compare alternative ways of taking information into account in light of cognitive shortcomings like our own. This paper is a preliminary attempt to do so. I argue that it is better, in a range (...) of circumstances and from the point of view of expected credal accuracy, for epistemic subjects like us not to update on available information that bears on propositions for which substantial evidence has been gathered than it is to update on information as it presents itself. In order to clarify the argument, and enable comparisons between information-response policies more generally, I develop a queue-theoretic model of learning for subjects with cognitive limitations. The model characterizes how policies for responding to information interact with a subject’s limitations to yield confidences. Finally, I discuss implications of the discussion for work on confidence, outright belief, and the relationship between those two states. The comparison of information-response policies helps to explain how some of the “biases” revealed by psychological research might be cognitively valuable, clarify views that take outright belief to be a kind of epistemic plan that resists reconsideration, and assuage certain “demandingness” worries for the hypothesis that we are credal reasoners. (shrink)