John Turri

Many philosophers claim that interesting forms of epistemic evaluation are insensitive to truth in a very specific way. Suppose that two possible agents believe the same proposition based on the same evidence. Either both are justified or neither is; either both have good evidence for holding the belief or neither does. This does not change if, on this particular occasion, it turns out that only one of the two agents has a true belief. Epitomizing this line of thought are thought experiments about radically deceived “brains in vats.” It is widely and uncritically assumed that such a brain is equally justified as its normally embodied human “twin.” This “parity” intuition is the heart of truth-insensitive theories of core epistemological properties such as justification and rationality. Rejecting the parity intuition is considered radical and revisionist. In this paper, I show that exactly the opposite is true. The parity intuition is idiosyncratic and widely rejected. A brain in a vat is not justified and has worse evidence than its normally embodied counterpart. On nearly every ordinary way of evaluating beliefs, a false belief is significantly inferior to a true belief. Of all the evaluations studied here, only blamelessness is truth-insensitive.

What is the relationship between saying ‘I know that Q’ and guaranteeing that Q? John Austin, Roderick Chisholm and Wilfrid Sellars all agreed that there is some important connection, but disagreed over what exactly it was. In this paper I discuss each of their accounts and present a new one of my own. Drawing on speech-act theory and recent research on the epistemic norms of speech acts, I suggest that the relationship is this: by saying ‘I know that Q’, you represent yourself as having the authority to guarantee that Q.

Can judging that an agent blamelessly broke a rule lead us to claim, paradoxically, that no rule was broken at all? Surprisingly, it can. Across seven experiments, we document and explain the phenomenon of excuse validation. We found when an agent blamelessly breaks a rule, it significantly distorts people’s description of the agent’s conduct. Roughly half of people deny that a rule was broken. The results suggest that people engage in excuse validation in order to avoid indirectly blaming others for blameless transgressions. Excuse validation has implications for recent debates in normative ethics, epistemology and the philosophy of language. These debates have featured thought experiments perfectly designed to trigger excuse validation, inhibiting progress in these areas

It is increasingly recognized that knowledge is the norm of assertion. As this view has gained popularity, it has also garnered criticism. One widely discussed criticism involves thought experiments about “selfless assertion.” Selfless assertions are said to be intuitively compelling examples where agents should assert propositions that they don’t even believe and, hence, don’t know. This result is then taken to show that knowledge is not the norm of assertion. This paper reports four experiments demonstrating that “selfless assertors” are viewed as both believing and knowing the propositions they assert: this is the natural and intuitive way of interpreting the case. Thought experiments about selfless assertions do not threaten the knowledge account and they do not motivate weaker alternative accounts. The discussion also highlights a general lesson for philosophers: thought experiments intended to probe for mental state attributions should not conflict with basic principles that guide social cognition

Contemporary philosophers nearly unanimously endorse knowledge reliabilism, the view that knowledge must be reliably produced. Leading reliabilists have suggested that reliabilism draws support from patterns in ordinary judgments and intuitions about knowledge, luck, reliability, and counterfactuals. That is, they have suggested a proto-reliabilist hypothesis about “commonsense” or “folk” epistemology. This paper reports nine experimental studies (N = 1262) that test the proto-reliabilist hypothesis by testing four of its principal implications. The main findings are that (a) commonsense fully embraces the possibility of unreliable knowledge, (b) knowledge judgments are surprisingly insensitive to information about reliability, (c) “anti-luck” intuitions about knowledge have nothing to do with reliability specifically, and (d) reliabilists have mischaracterized the intuitive counterfactual properties of knowledge and their relation to reliability. When combined with the weakness of existing arguments for reliabilism and the recent emergence of well supported alternative views that predict the widespread existence of unreliable knowledge, the present findings are the final exhibit in a conclusive case for abandoning reliabilism in epistemology. I introduce an alternative theory of knowledge, abilism, which out-performs reliabilism and well explains all the available evidence.

Infinitism, along with foundationalism and coherentism, is a logically possible solution to the epistemic regress problem. But unlike the other two views, infinitism has only been developed and defended as a plausible solution since the late 1990’s. Infinitists grant that although there is an ending point of any actual chain of cited reasons for a belief, no belief (including the last one cited) is fully justified until a reason for it is provided. In addition to differing with foundationalism about the existence of so-called basic beliefs, infinitism depicts reasoning as a process through which full doxastic justification is generated, rather than as a device for merely transferring doxastic justification from one belief to another. Thus, like coherentism, infinitism attempts to account for the origin of epistemic doxastic justification without invoking self-justified beliefs whose justification is transmitted through reasoning. But infinitism parts company with coherentism by maintaining (1) that circular reasoning is unable to provide a doxastic justification for any belief and (2) that there is a linear epistemic structure of our beliefs that reflects the fact that some beliefs are epistemically prior to others.

Traditionally it has been thought that the moral valence of a proposition is, strictly speaking, irrelevant to whether someone knows that the proposition is true, and thus irrelevant to the truth-value of a knowledge ascription. On this view, it’s no easier to know, for example, that a bad thing will happen than that a good thing will happen (other things being equal). But a series of very surprising recent experiments suggest that this is actually not how we view knowledge. On the contrary, people are much more willing to ascribe knowledge of a bad outcome. This is known as the epistemic side-effect effect (ESEE), and is a specific instance of a widely documented phenomenon, the side-effect effect (a.k.a. “the Knobe effect”), which is the most famous finding in experimental philosophy. In this paper, I report a new series of five experiments on ESEE, and in the process accomplish three things. First, I confirm earlier findings on the effect. Second, I show that the effect is virtually unlimited. Third, I introduce a new technique for detecting the effect, which potentially enhances its theoretical significance. In particular, my findings make it more likely that the effect genuinely reflects the way we think about and ascribe knowledge, rather than being the result of a performance error.

According to factive accounts of the norm of belief and decision-making, you should not believe or base decisions on a falsehood. Even when the evidence misleadingly suggests that a false proposition is true, you should not believe it or base decisions on it. Critics claim that factive accounts are counterintuitive and badly mischaracterize our ordinary practice of evaluating beliefs and decisions. This paper reports four experiments that rigorously test the critic’s accusations and the viability of factive accounts. The results undermine the accusations and provide the best evidence yet of factive norms of belief and decision-making. The results also help discriminate between two leading candidates for a factive norm: truth and knowledge. Knowledge is the superior candidate.

Any satisfactory epistemology must account for the distinction between propositional and doxastic justification. Can infinitism account for it? Proposals to date have been unsatisfactory. This paper advances a new infinitist account of the distinction. The discussion proceeds as follows. Section 1 sets the stage. Section 2 presents Peter Klein's account. Section 3 raises a problem for Klein's account and suggests an improvement. Section 4 raises a further challenge. Sections 5 to 7 consider several unsuccessful attempts to meet the challenge. Section 8 presents my new proposal, which can meet the challenge. Section 9 concludes the discussion.

Moderate scientism is the view that empirical science can help answer questions in nonscientific disciplines. In this paper, we evaluate moderate scientism in philosophy. We review several ways that science has contributed to research in epistemology, action theory, ethics, philosophy of language, and philosophy of mind. We also review several ways that science has contributed to our understanding of how philosophers make judgments and decisions. Based on this research, we conclude that the case for moderate philosophical scientism is strong: scientific practice has promoted significant progress in philosophy and its further development should be welcomed and encouraged.

Prior work on weakness of will has assumed that it is a thoroughly psychological phenomenon. At least, it has assumed that ordinary attributions of weakness of will are purely psychological attributions, keyed to the violation of practical commitments by the weak-willed agent. Debate has recently focused on which sort of practical commitment, intention or normative judgment, is more central to the ordinary concept of weakness of will. We report five experiments that significantly advance our understanding of weakness of will attributions by showing that the ordinary concept of weakness of will is less thoroughly psychological than the philosophical debate has assumed. We begin by showing that a sizable minority of people attribute weakness of will even in the absence of a violated commitment (Experiment 1). We then show that weakness of will attributions are sensitive to two important non-psychological factors. First, for actions stereotypically associated with weakness of will, the absence of certain commitments often triggers weakness of will attributions (Experiments 2–4). Second, the quality of an action’s outcome affects the extent to which an agent is viewed as weak-willed: actions with bad consequences are more likely to be viewed as weak-willed (Experiment 5). Our most important finding is that the ordinary concept of weakness of will is sensitive to two non-psychological factors and is thus much broader than philosophers have thus far imagined. We conclude by suggesting a two-tier model that unites our findings with traditional philosophical theorizing about weakness of will.

EPISTEMOLOGY “This is a superb companion to Epistemology: An Anthology. It consists of sixty commentaries, one for each of the sixty entries in that anthology. Turri is an extremely lucid writer, with a wonderful knack for finding and laying out argumentative structure, and for explaining crucial concepts. His commentary will greatly aid student comprehension and enhance class discussion.” Ernest Sosa, Rutgers University “Turri’s discussions are engaging and lucid. They are written for beginning students and will serve that purpose beautifully, but they are so well done that even veteran epistemologists will find them helpful.” John Greco, Saint Louis University Epistemology: A Guide is a straightforward and accessible introduction to contemporary epistemology for those studying the topic for the first time. It introduces and explains the main arguments of the most influential publications in the field from the last 50 years. Balancing simplicity of argument with accuracy and detail, this guide covers the central topics of theory of knowledge, including skepticism, epistemic justification, epistemic closure, virtue epistemology, and naturalized epistemology. Instead of artificially treating themes in isolation, it provides a clear context for key topics and concepts. Designed to stand alone or to accompany the second edition of Epistemology: An Anthology (Wiley Blackwell, 2008), this is a deft and concise introduction to a foundational topic in philosophy.

Six hundred three people completed a survey measuring perceptions of traditional areas of philosophical inquiry and their relationship to empirical science. The ten areas studied were: aesthetics, epistemology, ethics, history of philosophy, logic, metaphysics, philosophy of language, philosophy of mind, philosophy of science, and political philosophy. For each area, participants rated whether it is currently central to philosophy, whether its centrality depends on integration with science, and whether work in the area is sufficiently integrated with science. Centrality judgments tended to be high. Participants viewed nine of the ten areas as central to philosophy, although they made this judgment more confidently for some areas. Dependence judgments were more varied, ranging from clear disagreement to clear agreement. Integration judgments were also varied but exhibited more uncertainty. Some areas whose centrality depended on integration were judged to be well integrated, but a central tendency for all other areas was ambivalence. Demographic factors had small but statistically significant effects on all three sorts of judgment. Higher age predicted higher centrality judgments and higher integration judgments. Higher socioeconomic status predicted lower dependence judgments and higher integration judgments. Men recorded higher integration judgments.

The epistemic closure principle says that knowledge is closed under known entailment. The closure principle is deeply implicated in numerous core debates in contemporary epistemology. Closure’s opponents claim that there are good theoretical reasons to abandon it. Closure’s proponents claim that it is a defining feature of ordinary thought and talk and, thus, abandoning it is radically revisionary. But evidence for these claims about ordinary practice has thus far been anecdotal. In this paper, I report five studies on the status of epistemic closure in ordinary practice. Despite decades of widespread assumptions to the contrary in philosophy, ordinary practice is ambivalent about closure. Ordinary practice does not endorse an unqualified version of the epistemic closure principle, although it might endorse a source-relative version of the principle. In particular, whereas inferential knowledge is not viewed as closed under known entailment, perceptual knowledge might be