Ted Poston

Inference to the best explanation (IBE)—sometimes called ‘abduction’—is a way of reasoning that we rely on all the time, both in everyday life and in scientific practice. Even though it is remarkably common, IBE is often discussed in loose or imprecise terms. That lack of clarity leaves room for several well-known objections that, in many cases, can be avoided once we spell out more carefully what IBE actually involves. At its core, IBE tells us to accept the explanation that does the best job of making sense of the evidence, but only if that explanation is genuinely good enough to deserve our confidence. Once this condition is made explicit, some influential criticisms lose much of their force. Other objections, however, may re- main serious challenges for anyone who thinks IBE is a legitimate way to reason. Supporters of IBE have developed a variety of responses to these concerns, and the debate continues. This chapter clarifies what IBE is, surveys the major objections raised against it, and highlights the most promising strategies for answering those objections.

Public evidence plays a central role in the justification of scientific theories—but does its importance extend beyond science, for instance, to political or religious belief? To address this question, we first need a clear account of public evidence. This article develops such an account, characterizing public evidence as non‐experiential evidence that meets the non‐factive epistemic conditions for common knowledge. I argue that public evidence not only underwrites the justification of scientific theories but also constrains how experience can justify belief more generally. The result is a novel account of public evidence with broad applicability across domains of inquiry.

This chapter examines the problem of skepticism about the past within Richard Fumerton’s acquaintance theory of non-inferential justification. Acts of acquaintance occur within the fleeting present. But if the data for non-inferential justification are limited to the fleeting present then the options for avoiding a far-reaching skepticism are quite limited. This chapter considers Fumerton’s responses to skepticism about the past and argues that his acquaintance theory is not able to stave off skepticism about the past. Furthermore, it is argued that the bounds of skepticism about the past overflow to the fleeting present by limiting the kind of content knowable within the present ‘now.’ Finally, this chapter defends an epistemic conservative response to this stark skeptical problem by arguing that it is a theoretically economical account of the justification for beliefs about the past.

Social evil is any pain or suffering brought about by game-theoretic interactions of many individuals. This chapter introduces and discusses social evil. It begins with social evil brought about by game-theoretic interactions of rational moral individuals. The problem social evil poses for theism is distinct from the problems of natural and moral evils. Social evil is not a natural evil because it is brought about by the choices of individuals. But social evil is not a form of moral evil because each individual actor does not misuse his free will. Traditional defenses for natural and moral evil fall short in addressing social evil. The final section discusses social evil and virtue. It is argued that social evil arises even when all the participants are truly virtuous. The conclusion of this chapter is that social evil is problematic and provides new ground for exploring the conceptual resources of theism.

Public evidence plays a central role in the justification of scientific theories—but does its importance extend beyond science, for instance, to political or religious belief? To address this question, we first need a clear account of public evidence. This paper de- velops such an account, characterizing public evidence as non-experiential evidence that meets the non-factive epistemic conditions for common knowledge. I argue that public evidence not only underwrites the justification of scientific theories but also constrains how experience can justify belief more generally. The result is a novel account of public evidence with broad applicability across domains of inquiry.

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 (5): 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.

Bas van Fraassen has argued that explanatory reasoning does not provide confirmation for explanatory hypotheses because explanatory reasoning increases information and increasing information does not provide confirmation. We compare this argument with a skeptical argument that one should never add any beliefs because adding beliefs increases information and increasing information does not provide confirmation. We discuss the similarities between these two arguments and identify several problems with van Fraassen’s argument.

Evidentialism is one of the most sensible claims of recent philosophy. Yet it is often joined with other theses about the structure of justification and the nature of experience that are dubious. In this paper, I argue that experience is not a basic source of evidence. I contend that for an experience to justify a belief, it must be independently plausible that the experience is reliable based on background information. The paper develops an account of plausibility and examines cases, including differences in expertise, clairvoyance, and social perceptions, to illustrate how background knowledge is necessary for the justification of experiential beliefs. I consider challenges from Bergmann's distinction between learned and unlearned doxastic responses and Lyons's inferential reliabilism. I conclude that these challenges do not succeed; perceptual evidence requires a broader perspective that supports the reliability of the experiential evidence.

Explanation and evidence are related in one way that is uncontroversial: evidence can confirm or disconfirm explanations. One explanation of Sally’s cold is that she has a virus; another is that she has a bacterial infection. The available evidence confirms the virus explanation because the evidence supports that colds are caused by viruses, not bacteria. A more interesting question concerns whether explanatory facts themselves provide evidence. That is to say, do we get evidence for p simply by realizing that p, if true, would explain some data? Explanationists answer this question affirmatively, maintaining that explanatoriness is evidence of truth

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.

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.

Chalmers (The character of consciousness, 2010) argues for an acquaintance theory of the justification of direct phenomenal beliefs. A central part of this defense is the claim that direct phenomenal beliefs are cognitively significant. I argue against this. Direct phenomenal beliefs are justified within the specious present, and yet the resources available with the present ‘now’ are so impoverished that it barely constrains the content of a direct phenomenal belief. I argue that Chalmers’s account does not have the resources for explaining how direct phenomenal beliefs support the inference from ‘this E is R’ to ‘that was R.’

Functionalism about truth is the view that truth is an explanatorily significant but multiply-realizable property. According to this view the properties that realize truth vary from domain to domain, but the property of truth is a single, higher-order, domain insensitive property. We argue that this view faces a challenge similar to the one that Jaegwon Kim laid out for the multiple realization thesis. The challenge is that the higher-order property of truth is equivalent to an explanatorily idle disjunction of its realization bases. This consequence undermines the alethic functionalists’ non-deflationary ambitions. A plausible response to Kim’s argument fails to carry over to alethic functionalism on account of significant differences between alethic functionalism and psychological functionalism. Lynch’s revised view in his book Truth as One and Many ( 2009 ) fails to answer our challenge. The upshot is that, while mental functionalism may survive Kim’s argument, it mortally wounds functionalism about truth

Social evil is any pain or suffering brought about by game-theoretic interactions of many individuals. This paper introduces and discusses the problem of social evil. I begin by focusing on social evil brought about by game-theoretic interactions of rational moral individuals. The problem social evil poses for theism is distinct from problems posed by natural and moral evils. Social evil is not a natural evil because it is brought about by the choices of individuals. But social evil is not a form of moral evil because each individual actor does not misuse his free will. Traditional defenses for natural and moral evil fall short in addressing the problem of social evil. The final section of this paper discusses social evil and virtue. I begin by arguing that social evil can arise even when individual virtue is lacking. Next, I explore the possibility of an Edwardsian defense of social evil that stresses the high demands of true virtue. In this context, I argue that social evil may arise even when all the participants are truly virtuous. The conclusion of this paper is that social evil is problematic and provides new ground for exploring the conceptual resources of theism.