An a priori thesis about evidence, defended by many, states that the only empirical fact that can affect the truth of an objective evidence claim of the form ‘e is evidence for h’ (or ‘e confirms h to degree r’) is the truth of e; all other considerations are a priori. By examining cases involving evidential flaws, I challange this claim and defend an empirical concept of evidence. In accordance with such a concept, whether, and the extent to which, e, (...) if true, confirms h is an empirical, not a priori, fact. (shrink)

Two theses are central to recent work on the epistemology of disagreement: Equal Weight (‘EW’): In cases of epistemic peer disagreement, one should give equal weight to the attitude of a peer and to one’s own attitude.1 Uniqueness (‘U’): For any given proposition and total body of evidence, some doxastic attitude is the one the evidence makes rational (justifies) toward that proposition.

Evidence is often taken to be foundational, in that while other propositions may be inferred from our evidence, evidence propositions are themselves not inferred from anything. I argue that this conception is false, since the non-inferential propositions on which beliefs are ultimately founded may be forgotten or undermined in the course of enquiry.

In this paper I consider whether there can be such things as epistemic reasons for action. I consider three arguments to the contrary and argue that none are successful, being either somewhat question-begging or too strong by ruling out what most epistemologists think is a necessary feature of epistemic justification, namely the epistemic basing relation. I end by suggesting a "non-cognitivist" model of epistemic reasons that makes room for there being epistemic reasons for action and suggest that this model may (...) support moral realism. (shrink)

Many philosophers have claimed that evidence for a theory is better when multiple independent tests yield the same result, i.e., when experimental results are robust. Little has been said about the grounds on which such a claim rests, however. The present essay presents an analysis of the evidential value of robustness that rests on the fallibility of assumptions about the reliability of testing procedures and a distinction between the strength of evidence and the security of an evidence claim. Robustness can (...) enhance the security of an evidence claim either by providing what I call second-order evidence, or by providing back-up evidence for a hypothesis. (shrink)

Contemporary ways of understanding of science, especially in the philosophy of science, are beset by overly abstract and formal models of evidence. In such models, the only interesting feature of evidence is that it has a one-way ``support'' relation to hypotheses, theories, causal claims, etc. These models create a variety of practical and philosophical problems, one prominent example being the experimenter's regress. According to the experimenter's regress, good evidence is produced by good techniques, but which techniques are good is only (...) determined by whether they produce the evidence we expect. The best answer to this problem within the traditional approach relies on the concept of robust evidence, but this answer ultimately falls flat because it creates impossible requirements on good evidence. The problem can more easily be solved by rejecting abstract, formalistic models of evidence in favor of a model of inquiry which pays attention to the temporal complexity of the process of inquiry and the distinction between observational and experimental evidence. (shrink)

The likelihood theory of evidence (LTE) says, roughly, that all the information relevant to the bearing of data on hypotheses (or models) is contained in the likelihoods. There exist counterexamples in which one can tell which of two hypotheses is true from the full data, but not from the likelihoods alone. These examples suggest that some forms of scientific reasoning, such as the consilience of inductions (Whewell, 1858. In Novum organon renovatum (Part II of the 3rd ed.). The philosophy of (...) the inductive sciences. London: Cass, 1967), cannot be represented within Bayesian and Likelihoodist philosophies of science. (shrink)

, Peter Achinstein argues against the long-standing claim that ‘evidence’ is ambiguous in possessing a sense of confirming evidence and a sense of supporting evidence. He argues that explications of supporting evidence will necessarily violate his contentions that evidence is a discontinuous ‘threshold concept’ and that any philosophical account of supporting evidence will be too weak to be useful to working scientists. But an account of supporting evidence may be formulated which includes Achinstein's notion of epistemic thresholds that finds examples (...) in Achinstein's own historical case studies. Thresholds and the denial of ambiguity Achinstein's new account of confirming evidence Achinstein's argument against the ‘ambiguity response’ A threshold-based approach for restoring the ambiguity Maxwell and ‘a subject of rational curiosity’ Bohr and ‘future development of our understanding’ Perrin and the edge of reasonable belief Restoring ambiguity. (shrink)

In this paper, we argue for a particular informative and unified analysis of normative reasons. According to this analysis, a fact F is a reason to act in a certain way just in case it is evidence that one ought to act in that way. Similarly, F is a reason to believe a certain proposition just in case it is evidence for the truth of this proposition. Putting the relatively uncontroversial claim about reasons for belief to one side, we present (...) several arguments in favor of our analysis of reasons for action. We then turn to consider a series of objections to the analysis. We conclude that there are good reasons to accept the analysis and that the objections do not succeed. (shrink)

I defend the first premise of William Rowe’s well-known arguments from evil against influential criticisms due to William Alston. I next suggest that the central inference in Rowe’s arguments is best understood to move from the claim that we have an absence of evidence of a satisfactory theodicy to the claim that we have evidence of absence of such a theodicy. I endorse the view which holds that this move succeeds only if it is reasonable to believe that (roughly) if (...) there were such a theodicy, we would probably know it. After conceding that there may be modest prima facie support for this latter claim via the Principle of Credulity, I consider and reject four more ambitious arguments in its favour. I conclude that this necessary condition on Rowe’s crucial inference has not been shown to be satisfied. (shrink)

Since Ramsey, much discussion of the relation between probability and belief has taken for granted that there are degrees of belief, i.e., that there is a real-valued function, B, that characterizes the degree of belief that an agent has in each statement of his language. It is then supposed that B is a probability. It is then often supposed that as the agent accumulates evidence, this function should be updated by conditioning: BE(·) should be B(·E)/B(E). Probability is also important in (...) classical statistics, where it is generally supposed that probabilities are frequencies, and that inference proceeds by controlling error and not by conditioning. I will focus on the tension between these two approaches to probability, and in the main part of the paper show where and when Bayesian conditioning conflicts with error based statistics and how to resolve these conflicts. (shrink)

The fundamental constants that are involved in the laws of physics which describe our universe are finely tuned for life, in the sense that if some of the constants had slightly different values life could not exist. Some people hold that this provides evidence for the existence of God. I will present a probabilistic version of this fine-tuning argument which is stronger than all other versions in the literature. Nevertheless, I will show that one can have reasonable opinions such that (...) the fine-tuning argument doesn't lead to an increase in one's probability for the existence of God. The fine-tuning argument Objective versus subjective probability Observational selection effects The problem of old evidence Against the fine-tuning argument Many universes. (shrink)

Evidence-based approaches to policy-making are growing in popularity. A generally embraced view is that with the appropriate evidence at hand, decision and policy making will be optimal, legitimate and publicly accountable. In practice, however, evidence-based policy making is constrained by a variety of problems of evidence. Some of these problems will be explored in this article, in the context of the debates on evidence from which they originate. It is argued that the source of much disagreement might be a failure (...) to addressing crucial philosophical assumptions that inform, often silently, these debates. Three controversial questions will be raised which appear central to some of the challenges faced by evidence-based policy making: firstly, how do certain types of facts candidate themselves as evidence; secondly, how do we decide what evidence we have, and how much of it; and thirdly, can we combine evidence. In addressing these questions it will be shown how a philosophically informed debate might prove instrumental in clarifying and settling practical difficulties. (shrink)

The Variety of Evidence Thesis (VET) says that (ceteris paribus) the more diverse (or varied) of two bodies of evidence is the more confirmatory of a hypothesis H. Two recent types of Bayesian explication of VET account for the intuitive force of VET by defining variety as some function of the probabilities of the propositions which collectively constitute a body of evidence. I show that these two accounts of VET are not tracking a meaningful property of bodies of evidence, but (...) rather are tracking artifacts of how those bodies of evidence are described. According to each account, whether a body of evidence is more varied than another depends on how the bodies are split into parts. Furthermore, for each type of account there exists a way to redescribe the total evidence such that any two totalities are equally varied. ‡I would like to thank Elliott Sober for comments on multiple drafts of this paper, and Malcolm Forster, John Koolage, and Joel Velasco for comments on a verbal delivery. †To contact the author, please write to: Department of Philosophy, University of Wisconsin-Madison, 5185 Helen C. White Hall, 600 North Park Street, Madison, WI 53706; e-mail: gmnovack@wisc.edu. (shrink)

Holistic claims about evidence are a commonplace inthe philosophy of science; holistic claims aboutmeaning are a commonplace in the philosophy oflanguage. W. V. Quine has advocated both types ofholism, and argued for an intimate link between thetwo. Semantic holism may be inferred from theconjunction of confirmation holism andverificationism, he maintains. But in their recentbook Holism: a Shopper's Guide, Jerry Fodor andErnest Lepore (1992) claim that this inference isfallacious. In what follows, I defend Quine's argumentfor semantic holism from Fodor and Lepore'smulti-pronged (...) attack. (shrink)

This paper attempts to argue for the theory-ladenness of evidence. It does so by employing and analysing an episode from the history of eighteenth century chemistry. It delineates attempts by Joseph Priestley and Antoine Lavoisier to construct entirely different kinds of evidence for and against a particular hypothesis from a set of agreed upon observations or (raw) data. Based on an augmented version of a distinction, drawn by J. Bogen and J. Woodward, between data and phenomena it is shown that (...) the role of theoretical auxiliary assumptions is very important in constructing evidence for (or against) a theory from observation or (raw) data. In revolutionary situations, rival groups hold radically different theories and theoretical auxiliary assumptions. These are employed to construct very different evidence from the agreed upon set of observations or (raw) data. Hence, theory resolution becomes difficult. It is argued that evidence construction is a multi-layered exercise and can be disputed at any level. What counts as unproblematic observation or (raw) data at one level may become problematic at another level. The contingency of these constructions and the (un)problematic nature of evidence are shown to be partially dependent upon the scientific knowledge that the scientific community possesses. (shrink)

Taking its clues from Popperian philosophy of science, cladistics adopted a number of assumptions of the empiricist tradition. These include the identification of a dichotomy between observation reports and theoretical statements and its subsequent abandonment on the basis of the insight that all observation reports are theory-laden. The neglect of the ‘context of discovery’, which is the step of theory (hypothesis) generation. The emphasis on coherentism in the ‘context of justification’, which is the step of evaluation of the relative merits (...) of alternative theories. The appeal to a total evidence approach in phylogenetic inference. And finally, a silence about causation, which results in an instrumentalist approach to phylogeny reconstruction. This paper explores how these empiricist assumptions are embedded in phylogenetic systematics, and why these assumptions are problematic for cladists (or any taxonomists). (shrink)

I contrast two modes of error-elimination relevant to evaluating evidence in accounts that emphasize frequentist reliability. The contrast corresponds to that between the use of of a reliable inference procedure and the critical scrutiny of a procedure with regard to its reliability, in light of what is and is not known about the setting in which the procedure is used. I propose a notion of security as a category of evidential assessment for the latter. In statistical settings, robustness theory and (...) misspecification testing exemplify two distinct strategies for securing statistical inferences. (shrink)

From the perspective of Mayo’s error statistical theory of evidence, I explore problems and prospects for an account of the objectivity of scientific evidence. A recent proposal by Peter Achinstein provides the starting point. I consider a challenge to this proposal arising from the role of agents in carrying out the testing procedures that are central to the error statistical theory. Achinstein’s objective concept of unrelativized potential evidence initially resolves these difficulties, only to give way to a deeper incompatibility between (...) Achinstein’s conception of objectivity of reasons to believe and the error statistical theory of evidence. I propose an alternative account of objectivity of reasons that is compatible with the error statistical theory. (shrink)