John Turri

Indicative judgments pertain to what is true. Epistemic modal judgments pertain to what must or might be true relative to a body of information. A standard view is that epistemic modals implicitly quantify over alternative possibilities, or ways things could turn out. On this view, a proposition must be true just in case it is true in all the possibilities consistent with the available information, and a proposition might be true just in case it is true in at least one possibility consistent with the available information. I report three experiments testing this view of epistemic modals. The results show that although modal judgments are sensitive to information about alternative possibilities, the standard quantification theory mischaracterizes the ordinary meaning of modals. I then report two more experiments testing the hypothesis that epistemic modals express willingness to attribute knowledge based on the available information. The results support this hypothesis. The results also show that the difference between “inside” and “outside” probabilistic information, familiar from the judgment and decision-making literature, affects epistemic modal judgments.

Language is a human universal reflecting our deeply social nature. Among its essential functions, language enables us to quickly and efficiently share information. We tell each other that many things are true—that is, we routinely make assertions. Information shared this way plays a critical role in the decisions and plans we make. In Knowledge and the Norm of Assertion, a distinguished philosopher and cognitive scientist investigates the rules or norms that structure our social practice of assertion. Combining evidence from philosophy, psychology, and biology, John Turri shows that knowledge is the central norm of assertion and explains why knowledge plays this role. Concise, comprehensive, non-technical, and thoroughly accessible, this volume quickly brings readers to the cutting edge of a major research program at the intersection of philosophy and science. It presupposes no philosophical or scientific training. It will be of interest to philosophers and scientists, is suitable for use in graduate and undergraduate courses, and will appeal to general readers interested in human nature, social cognition, and communication.

An impressive case has been built for the hypothesis that knowledge is the norm of assertion, otherwise known as the knowledge account of assertion. According to the knowledge account, you should assert something only if you know that it’s true. A wealth of observational data supports the knowledge account, and some recent empirical results lend further, indirect support. But the knowledge account has not yet been tested directly. This paper fills that gap by reporting the results of such a test. The knowledge account passes with flying colors

I evaluate two new objections to an infinitist account of epistemic justification, and conclude that they fail to raise any new problems for infinitism. The new objections are a refined version of the finite-mind objection, which says infinitism demands more than finite minds can muster, and the normativity objection, which says infinitism entails that we are epistemically blameless in holding all our beliefs. I show how resources deployed in response to the most popular objection to infinitism, the original finite-mind objection, can be redeployed to address the two new objections

Epistemic contextualism is one of the most hotly debated topics in contemporary epistemology. Contextualists claim that ‘know’ is a context-sensitive verb associated with different evidential standards in different contexts. Contextualists motivate their view based on a set of behavioural claims. In this paper, I show that several of these behavioural claims are false. I also show that contextualist test cases suffer from a critical confound, which derives from people's tendency to defer to speakers’ statements about their own mental states. My evidence consists in results from several behavioural experiments. I conclude that contextualism is an idle hypothesis and I propose some general methodological lessons.

Recent work has assumed that the normativity associated with assertion differs from the normativity of morality, practical rationality, etiquette, and legality. That is, whether an assertion “should” be made is not merely a function of these other familiar sorts of normativity and is especially connected to truth. Some researchers have challenged this assumption of distinctive normativity. In this paper I report two experiments that test the assumption. Participants read a brief story, judged whether an assertion should be made, and rated several other qualities of the assertion, including its truth value, morality, rationality, etiquette, legality, and folly. Of these qualities, truth value most strongly predicted assertability. The findings support the assumption of distinctive normativity and provide further evidence that the norm of our social practice of assertion is factive.

This paper presents a puzzle about justification and withholding. The puzzle arises in a special case where experts advise us to not withhold judgment. My main thesis is simply that the puzzle is genuinely a puzzle, and so leads us to rethink some common assumptions in epistemology, specifically assumptions about the nature of justification and doxastic attitudes. Section 1 introduces the common assumptions. Section 2 presents the puzzle case. Section 3 assesses the puzzle case. Section 4 explains the choice we're faced with. Sections 5 and 6 consider and reject some proposed solutions, and in the process refine and clarify the choice we're faced with. Section 7 considers and rejects a miscellany of different proposed solutions

It’s a cornerstone of epistemology that knowledge requires truth – that is, that knowledge is factive. Allan Hazlett boldly challenges orthodoxy by arguing thatthe ordinary concept of knowledge is not factive. On this basis Hazlett further argues that epistemologists shouldn’t concern themselves with the ordinary concept of knowledge, or knowledge ascriptions and related linguistic phenomena. I argue that either Hazlett is wrong about the ordinary concept of knowledge, or he’s right in a way that leaves epistemologists to carry on exactly as they have, paying attention to much the same things they always did.

Recent work has shown that knowledge attributions affect how people think others should behave, more so than belief attributions do. This paper reports two experiments providing evidence that knowledge attributions also affect behavioral predictions more strongly than belief attributions do, and knowledge attributions facilitate faster behavioral predictions than belief attributions do. Thus, knowledge attributions play multiple critical roles in social cognition, guiding judgments about how people should and will behave.

Leading virtue epistemologists defend the view that knowledge must proceed from intellectual virtue and they understand virtues either as refined character traits cultivated by the agent over time through deliberate effort, or as reliable cognitive abilities. Philosophical situationists argue that results from empirical psychology should make us doubt that we have either sort of epistemic virtue, thereby discrediting virtue epistemology’s empirical adequacy. I evaluate this situationist challenge and outline a successor to virtue epistemology: _abilism_. Abilism delivers all the main benefits of virtue epistemology and is as empirically adequate as any theory in philosophy or the social sciences could hope to be.

This paper clarifies and evaluates a premise of William Alston’s argument in Perceiving God. The premise in question: if it is practically rational to engage in a doxastic practice, then it is epistemically rational to suppose that said practice is reliable. I first provide the background needed to understand how this premise fits into Alston’s main argument. I then present Alston’s main argument, and proceed to clarify, criticize, modify, and ultimately reject Alston’s argument for the premise in question. Without this premise, Alston’s main argument fails.

Researchers have debated whether knowledge or certainty is a better candidate for the norm of assertion. Should you make an assertion only if you know it's true? Or should you make an assertion only if you're certain it's true? If either knowledge or certainty is a better candidate, then this will likely have detectable behavioral consequences. I report an experiment that tests for relevant behavioral consequences. The results support the view that assertability is more closely linked to knowledge than to certainty. In multiple scenarios, people were much more willing to allow assertability and certainty to come apart than to allow assertability and knowledge to come apart

Radical skepticism is the view that we know nothing or at least next to nothing. Nearly no one actually believes that skepticism is true. Yet it has remained a serious topic of discussion for millennia and it looms large in popular culture. What explains its persistent and widespread appeal? How does the skeptic get us to doubt what we ordinarily take ourselves to know? I present evidence from two experiments that classic skeptical arguments gain potency from an interaction between two factors. First, people evaluate inferential belief more harshly than perceptual belief. Second, people evaluate inferential belief more harshly when its content is negative (i.e., that something is not the case) than when it is positive (i.e., that something is the case). It just so happens that potent skeptical arguments tend to focus our attention on negative inferential beliefs, and we are especially prone to doubt that such beliefs count as knowledge. That is, our cognitive evaluations are biased against this specific combination of source and content. The skeptic sows seeds of doubt by exploiting this feature of our psychology

Is knowledge justified true belief? Most philosophers believe that the answer is clearly ‘no’, as demonstrated by Gettier cases. But Gettier cases don’t obviously refute the traditional view that knowledge is justified true belief (JTB). There are ways of resisting Gettier cases, at least one of which is partly successful. Nevertheless, when properly understood, Gettier cases point to a flaw in JTB, though it takes some work to appreciate just what it is. The nature of the flaw helps us better understand the nature of knowledge and epistemic justification. I propose a crucial improvement to the traditional view, relying on an intuitive and independently plausible metaphysical distinction pertaining to the manifestation of intellectual powers, which supplements the traditional components of justification, truth and belief.

There is a virtual consensus in contemporary epistemology that knowledge must be reliably produced. Everyone, it seems, is a reliabilist about knowledge in that sense. I present and defend two arguments that unreliable knowledge is possible. My first argument proceeds from an observation about the nature of achievements, namely, that achievements can proceed from unreliable abilities. My second argument proceeds from an observation about the epistemic efficacy of explanatory inference, namely, that inference to the best explanation seems to produce knowledge, even if it isn't reliable. I also propose a successor to standard versions of reliabilism, which I call ‘ecumenical reliabilism’. Ecumenical reliabilism is consistent with unreliably produced knowledge and helps explain why unreliably produced knowledge is possible.