This paper defends reductionism about testimonial justification of beliefs against two influential arguments. One is the empirical argument to the effect that the reductionist justification of our trust in testimony is either circular since it relies on testimonial evidence or else there is scarce evidence in support of our trust in testimony. The other is the transcendental argument to the effect that trust in testimony is a prerequisite for the very existence of testimonial evidence since without the presumption of people’s (...) truthfulness we cannot interpret their utterances as testimony with propositional contents. This paper contends that the epistemic subject can interpret utterances as testimony with propositional contents without presupposing the credibility of testimony, and that evidence available to the normal epistemic subject can justify her trust in testimony. (shrink)

It is a widely shared view among philosophers of science that the theory-dependence (or theory-ladenness) of observations is worrying, because it can bias empirical tests in favour of the tested theories. These doubts are taken to be dispelled if an observation is influenced by a theory independent of the tested theory and thus circularity is avoided, while (partially) circular tests are taken to require special attention. Contrary to this consensus, it is argued that the epistemic value of theory-dependent tests has (...) nothing to do with the circularity or non-circularity of the test, but is instead based on the minimal empiricality and reliability of observations. Since theory-dependence does not in general prevent observations fulfilling these requirements, it should not be regarded as a phenomenon that is basically detrimental, but as neutral with respect to successful scientific knowledge gathering. (shrink)

Everyday life reasoning and argumentation is defeasible and uncertain. I present a probability logic framework to rationally reconstruct everyday life reasoning and argumentation. Coherence in the sense of de Finetti is used as the basic rationality norm. I discuss two basic classes of approaches to construct measures of argument strength. The first class imposes a probabilistic relation between the premises and the conclusion. The second class imposes a deductive relation. I argue for the second class, as the first class is (...) problematic if the arguments involve conditionals. I present a measure of argument strength that allows for dealing explicitly with uncertain conditionals in the premise set. (shrink)

This is a draft of a chapter that has been accepted for publication by Oxford University Press in the forthcoming book "Ethics and Explanation", edited by Neil Sinclair and Uri Leibowitz due for publication in 2016.

We examine in detail three classic reasoning fallacies, that is, supposedly ``incorrect'' forms of argument. These are the so-called argumentam ad ignorantiam, the circular argument or petitio principii, and the slippery slope argument. In each case, the argument type is shown to match structurally arguments which are widely accepted. This suggests that it is not the form of the arguments as such that is problematic but rather something about the content of those examples with which they are typically justified. This (...) leads to a Bayesian reanalysis of these classic argument forms and a reformulation of the conditions under which they do or do not constitute legitimate forms of argumentation. (shrink)

Interpretation, Constraint, and the Prospects of Scientific Realism I explore the interaction between theory-based interpretations of scientific evidence and constraints on theories provided by that evidence. Interpretation is often viewed as a source of error and a reason for scepticism about scientific results. But, I argue, while interpretation does generate epistemic risk, it also points to new sources of evidence that can constrain our theories. This is especially clear in the development of instrumentation that increases the range of our interactions (...) with nature. While the design of such instruments and the interpretation of their outputs are deeply dependent on theory-based interpretations, these outputs can still challenge those very theories. At the same time, theory-guided instrumentation provides us access to aspects of nature that we cannot study with our unaided senses. This access allows us to extend the range of evidence that we collect, and thus increases the constraints on our theories. As a result, theory-guided evidence collection has a positive impact on the prospects of scientific realism since these increasing constraints on our theories provide our only reason for thinking that we may be approaching the development of true theories. (shrink)

In this article, we argue for the general importance of normative theories of argument strength. We also provide some evidence based on our recent work on the fallacies as to why Bayesian probability might, in fact, be able to supply such an account. In the remainder of the article we discuss the general characteristics that make a specifically Bayesian approach desirable, and critically evaluate putative flaws of Bayesian probability that have been raised in the argumentation literature.

Some think that recent empirical research has shown that peoples' moral intuitions vary in a way that is hard to reconcile with the supposition that they are even modestly reliable. This is in turn supposed to generate skeptical conclusions regarding the claims and theories advanced by ethicists because of the crucial role intuitions have in the arguments offered in support of those claims. I begin by trying to articulate the most compelling version of this challenge. On that version, the main (...) problem is the absence of a believable positive account of the reliability of the intuitions . I then consider the response to this challenge that, in my view, holds most promise. It differs from others by invoking substantive moral assumptions. Such a strategy may appear problematically circular, in that the justification of those assumptions seems to presuppose the very thesis that is challenged . However, although I think that objection can be met, I argue that there are other problems with the strategy. On the basis of a set of conditions that a successful defense of the pertinent kind plausibly must satisfy, I argue that the prospects of developing such an account are bleak. (shrink)

What are the consequences of evolutionary theory for the epistemic standing of our beliefs? Evolutionary considerations can be used to either justify or debunk a variety of beliefs. This paper argues that evolutionary approaches to human cognition must at least allow for approximately reliable cognitive capacities. Approaches that portray human cognition as so deeply biased and deficient that no knowledge is possible are internally incoherent and self-defeating. As evolutionary theory offers the current best hope for a naturalistic epistemology, evolutionary approaches (...) to epistemic justification seem to be committed to the view that our sensory systems and belief-formation processes are at least approximately accurate. However, for that reason they are vulnerable to the charge of circularity, and their success seems to be limited to commonsense beliefs. This paper offers an extension of evolutionary arguments by considering the use of external media in human cognitive processes: we suggest that the way humans supplement their evolved cognitive capacities with external tools may provide an effective way to increase the reliability of their beliefs and to counter evolved cognitive biases. (shrink)

This article assesses two major conceptual arguments against theories of choice.The first argument concerns the circularity of belief-desire psychology, on which decision theory is based. The second argument concerns the normativity arising from the concept of rationality. Each argument is evaluated against experimental practice in economics and psychology, and it is concluded that both arguments fail to establish their skeptical conclusion that there can be no science of intentional human actions.