Ted Poston

Bayesian approaches to rationality require that a person’s degrees of belief be coherent. Among other implications, coherence requires that a person has the same degree of belief in every logically equivalent proposition. However, a person can have evidence for a claim without having evidence for all its propositional equivalences. This paper explores this conflict and argues that a person may be perfectly rational by virtue of responding to their evidence, even if their credences are not coherent. The paper also challenges the idea that it is always better to have more coherent credence, highlighting the fundamental role that evidence plays in rational belief.

It is a widespread intuition that the coherence of independent reports provides a powerful reason to believe that the reports are true. Formal results by Huemer, M. 1997. “Probability and Coherence Justification.” Southern Journal of Philosophy 35: 463–72, Olsson, E. 2002. “What is the Problem of Coherence and Truth?” Journal of Philosophy XCIX : 246–72, Olsson, E. 2005. Against Coherence: Truth, Probability, and Justification. Oxford University Press., Bovens, L., and S. Hartmann. 2003. Bayesian Epistemology. Oxford University Press, prove that, under certain conditions, coherence cannot increase the probability of the target claim. These formal results, known as ‘the impossibility theorems’ have been widely discussed in the literature. They are taken to have significant epistemic upshot. In particular, they are taken to show that reports must first individually confirm the target claim before the coherence of multiple reports offers any positive confirmation. In this paper, I dispute this epistemic interpretation. The impossibility theorems are consistent with the idea that the coherence of independent reports provides a powerful reason to believe that the reports are true even if the reports do not individually confirm prior to coherence. Once we see that the formal discoveries do not have this implication, we can recover a model of coherence justification consistent with Bayesianism and these results. This paper, thus, seeks to turn the tide of the negative findings for coherence reasoning by defending coherence as a unique source of confirmation.

The coherence of independent reports provides a strong reason to believe that the reports are true. This plausible claim has come under attack from recent work in Bayesian epistemology. This work shows that, under certain probabilistic conditions, coherence cannot increase the probability of the target claim. These theorems are taken to demonstrate that epistemic coherentism is untenable. To date no one has investigated how these results bear on different conceptions of coherence. I investigate this situation using Thagard’s ECHO model of explanatory coherence. Thagard’s ECHO model provides a natural representation of the evidential significance of multiple independent reports.

This paper articulates a way to ground a relatively high prior probability for grand explanatory theories apart from an appeal to simplicity. I explore the possibility of enumerating the space of plausible grand theories of the universe by using the explanatory properties of possible views to limit the number of plausible theories. I motivate this alternative grounding by showing that Swinburne’s appeal to simplicity is problematic along several dimensions. I then argue that there are three plausible grand views—theism, atheism, and axiarchism—which satisfy explanatory requirements for plausibility. Other possible views lack the explanatory virtue of these three theories. Consequently, this explanatory grounding provides a way of securing a nontrivial prior probability for theism, atheism, and axiarchism. An important upshot of my approach is that a modest amount of empirical evidence can bear significantly on the posterior probability of grand theories of the universe.

Although inference to the best explanation is ubiquitous in science and our everyday lives, there are numerous objections to the viability of IBE. Many of these objections have been thoroughly discussed, however, at least one objection to IBE has not received adequate treatment. We term this objection the “Disjunction Objection”. This objection challenges IBE on the grounds that it seems that even if H is the best explanation, it could be that the disjunction of its rivals is more likely to be true. As a result, IBE appears to license accepting a hypothesis that is more likely than not to be false. Despite these initial appearances, we argue that the Disjunction Objection fails to impugn IBE.

Bradford Hill (1965) highlighted nine aspects of the complex evidential situation a medical researcher faces when determining whether a causal relation exists between a disease and various conditions associated with it. These aspects are widely cited in the literature on epidemiological inference as justifying an inference to a causal claim, but the epistemological basis of the Hill aspects is not understood. We offer an explanatory coherentist interpretation, explicated by Thagard's ECHO model of explanatory coherence. The ECHO model captures the complexity of epidemiological inference and provides a tractable model for inferring disease causation. We apply this model to three cases: the inference of a causal connection between the Zika virus and birth defects, the classic inference that smoking causes cancer, and John Snow’s inference about the cause of cholera.

Epistemic conservatism is the thesis that the mere holding of a belief confers some positive epistemic status on its content. Conservatism is widely criticized on the grounds that it conflicts with the main goal in epistemology to believe truths and disbelieve falsehoods. In this paper I argue for conservatism and defend it from objections. First, I argue that the objection to conservatism from the truth goal in epistemology fails. Second, I develop and defend an argument for conservatism from the perspectival character of the truth goal. Finally, I examine several forceful challenges to conservatism and argue that these challenges are unsuccessful. The first challenge is that conservatism implies the propriety of assertions like ‘I believe p and this is part of my justification for it’. The second challenge argues that conservatism wrongly implies that the identity of an epistemic agent is relevant to the main goal of believing truths and disbelieving falsehoods. The last two challenges I consider are the ‘extra boost’ objection and the conversion objection. Each of these objections helps to clarify the nature of the conservative thesis. The upshot of the paper is that conservatism is an important and viable epistemological thesis.

We know facts, but we also know how to do things. To know a fact is to know that a proposition is true. But does knowing how to ride a bike amount to knowledge of propositions? This is a challenging question and one that deeply divides the contemporary landscape. A Critical Introduction to Knowledge-How introduces, outlines, and critically evaluates various contemporary debates surrounding the nature of knowledge-how. Carter and Poston show that situating the debate over the nature of knowledge-how in other epistemological debates provides new ways to make progress. In particular, Carter and Poston explore the question of what knowledge-how involves, and how it might come apart from propositional knowledge, by engaging with key epistemological topics including epistemic luck, knowledge of language, epistemic value, virtue epistemology and social epistemology. New frontiers for research on knowledge-how are also explored relating to the internalism - externalism debate as well as embodied and extended knowledge. A Critical Introduction to Knowledge-How provides an accessible introduction to the main arguments in this important and thriving debate suited for undergraduates and postgraduates in philosophy and related areas. A strength of the book is its methodology which places a premium on placing the debates over knowledge-how in a broader conversation over the nature of knowledge. This book also offers an opinionated discussion of various lines of argument which will be of interest to professional philosophers as well.

Epistemic conservatism is the thesis that the mere holding of a belief confers some positive epistemic status on its content. Conservatism is widely criticized on the grounds that it conflicts with the main goal in epistemology to believe truths and disbelieve falsehoods. In this paper I argue for conservatism and defend it from objections. First, I argue that the objection to conservatism from the truth goal in epistemology fails. Second, I develop and defend an argument for conservatism from the perspectival character of the truth goal. Finally, I examine several forceful challenges to conservatism and argue that these challenges are unsuccessful. The first challenge is that conservatism implies the propriety of assertions like ‘I believe p and this is part of my justification for it’. The second challenge argues that conservatism wrongly implies that the identity of an epistemic agent is relevant to the main goal of believing truths and disbelieving falsehoods. The last two challenges I consider are the ‘extra boost’ objection and the conversion objection. Each of these objections helps to clarify the nature of the conservative thesis. The upshot of the paper is that conservatism is an important and viable epistemological thesis

Abstract This paper develops an explanationist treatment of the problem of the criterion. Explanationism is the view that all justified reasoning is justified in virtue of the explanatory virtues: simplicity, fruitfulness, testability, scope, and conservativeness. A crucial part of the explanationist framework is achieving wide reflective equilibrium. I argue that explanationism offers a plausible solution to the problem of the criterion. Furthermore, I argue that a key feature of explanationism is the plasticity of epistemic judgments and epistemic methods. The explanationist does not offer any fixed judgments or methods to guide epistemic conduct; even the explanatory virtues themselves are subject to change. This feature of explanationism gives it an advantage over non-explanationist views that offer fixed epistemic judgments and epistemic methods. The final section of this paper responds to objections to explanationism

William Roche and Elliott Sober argue that explanatoriness is evidentially irrelevant. This conclusion is surprising since it conflicts with a plausible assumption—the fact that a hypothesis best explains a given set of data is evidence that the hypothesis is true. We argue that Roche and Sober's screening-off argument fails to account for a key aspect of evidential strength: the weight of a body of evidence. The weight of a body of evidence affects the resiliency of probabilities in the light of new evidence. Thus, Roche and Sober are mistaken. Explanatoriness is evidentially relevant

Jason Stanley and Timothy Williamson's influential article "Knowing How" argues that knowledge-how is a species of knowledge-that. One objection to their view is that knowledge-how is significantly different than knowledge-that because Gettier cases afflict the latter but not the former. Stanley and Williamson argue that this objection fails. Their response, however, is not adequate. Moreover, I sketch a plausible argument that knowledge-how is not susceptible to Gettier cases. This suggests a significant distinction between knowledge-that and knowledge-how.

This paper develops and defends a coherentist account of reasons. I develop three core ideas for this defense: a distinction between basic reasons and noninferential justification, the plausibility of the neglected argument against first philosophy, and an emergent account of reasons. These three ideas form the backbone for a credible coherentist view of reasons. I work toward this account by formulating and explaining the basic reasons dilemma. This dilemma reveals a wavering attitude that coherentists have had toward basic reasons. More importantly, the basic reasons dilemma focuses our attention on the central problems that afflict coherentist views of basic beliefs. By reflecting on the basic reasons dilemma, I formulate three desiderata that any viable coherentist account of basic beliefs must satisfy. I argue that the account on offer satisfies these desiderata

Reason and Explanation develops a new explanationist account of epistemic justification. Poston argues that the explanatory virtues provide a plausible account of necessary and sufficient conditions for justification. The justification of a subject's belief consists in the explanatory virtue of her entire beliefs compared with other sets of beliefs she could have. Poston's argument for coherentism involves a defense of the epistemic value of background beliefs, the development of a novel framework view of reasons, and the articulation of a mentalism evidentialist account of coherentism. Poston argues against foundationalist views that ground justification in sense experience apart from supporting background beliefs. He extends the argument against foundationalism by examining a coherentist view of a priori knowledge. Finally, he articulates a compatiblist position regarding Bayesianism and inference to the best explanation.

This paper addresses the scatter problem for foundational evidentialism. Reflection on the scatter problem uncovers significant epistemological lessons. The scatter problem is evaluated in connection with Ernest Sosa’s use of the problem as an argument against foundational evidentialism. Sosa’s strategy is to consider a strong intuition in favor of internalism—the new evil demon problem, and then illustrate how a foundational evidentialist account of the new evil demon problem succumbs to the scatter problem. The goal in this paper is to evaluate the force of the scatter problem. The main argument of the paper is that the scatter problem has mixed success. On the one hand, scatter undermines objectual evidentialism, an evidentialist theory that formulates principles of basic perceptual justification in terms of the objects of perceptual states. On the other hand, the problem of scatter does not undermine content evidentialism, an evidentialist view that formulates its epistemic principles in terms of the assertive content of perceptual states. The significance of the scatter problem, especially in concert with the new evil demon problem, is that it provides an argument for content evidentialism.

Timothy Williamson’s anti luminosity argument has received considerable attention. Escaping unnoticed, though, is a strikingly similar argument from David Hume. This paper highlights some of the arresting parallels between Williamson’s reasoning and Hume’s that will allow us to appreciate more deeply the plausibility of Williamson’s reasoning and to understand how, following Hume, we can extend this reasoning to undermine the “luminosity” of simple necessary truths. More broadly the parallels help us to identify a common skeptical predicament underlying both arguments, which we shall call “the quarantine problem”. The quarantine problem expresses a deep skepticism about achieving any exalted epistemic state. Further, the perspective gained by the quarantine problem allows us to easily categorize existing responses to Williamson’s anti luminosity argument and to observe the deficiencies of those responses. In sum, the quarantine problem reveals the deeply fallibilistic nature of whatever knowledge we may possess.

We argue that there is a tension between two types of design arguments-the fine-tuning argument (FTA) and the biological design argument (BDA). The tension arises because the strength of each argument is inversely proportional to the value of a certain currently unknown probability. Since the value of that probability is currently unknown, we investigate the properties of the FTA and BDA on different hypothetical values of this probability. If our central claim is correct this suggests three results: 1. It is not very plausible that a cumulative case for theism include both the FTA and the BDA (with one possible qualification); 2. Self-organization scenarios do not threaten theism but in fact provide the materials for a good FTA. 3. A plausible design argument of one sort or another (either FTA or BDA) will be available for a wide variety of values of the key probability