John Turri

Many philosophers favour the simple knowledge account of assertion, which says you may assert something only if you know it. The simple account is true but importantly incomplete. I defend a more informative thesis, namely, that you may assert something only if your assertion expresses knowledge. I call this 'the express knowledge account of assertion', which I argue better handles a wider range of cases while at the same time explaining the simple knowledge account's appeal. §1 introduces some new data that a knowledge account of assertion well explains. §2 explains the simple knowledge account's advantage over two of its main competitors. §3 presents a problem for the simple account and offers a solution, which is to adopt the express knowledge account. §4 encapsulates the case for the express knowledge account, and offers a unifying vision for the epistemology of belief and assertion. §5 answers an objection. §6 briefly sums up. Even those who ultimately reject my conclusion can still benefit from the new data presented in §1, and learn an important lesson from the problem discussed in §3, which demonstrates a general constraint on an acceptable account of the norm of assertion.

Nearly all success is due to some mix of ability and luck. But some successes we attribute to the agent’s ability, whereas others we attribute to luck. To better understand the criteria distinguishing credit from luck, we conducted a series of four studies on knowledge attributions. Knowledge is an achievement that involves reaching the truth. But many factors affecting the truth are beyond our control and reaching the truth is often partly due to luck. Which sorts of luck are compatible with knowledge? We find that knowledge attributions are highly sensitive to lucky events that change the explanation for why a belief is true. By contrast, knowledge attributions are surprisingly insensitive to lucky events that threaten but ultimately fail to change the explanation for why a belief is true. These results shed light on our concept of knowledge, help explain apparent inconsistencies in prior work on knowledge attributions, and constitute progress toward a general understanding of the relation between success and luck.

Approximation involves representing things in ways that might be close to the truth but are nevertheless false. Given the widespread reliance on approximations in science and everyday life, here we ask whether it is conceptually possible for false approximations to qualify as knowledge. According to the factivity account, it is impossible to know false approximations, because knowledge requires truth. According to the representational adequacy account, it is possible to know false approximations, if they are close enough to the truth for present purposes. In this paper, we adopt an experimental methodology to begin testing these two theories. When an agent provides a false and practically inadequate answer, both theories predict that people will deny knowledge. But the theories disagree about an agent who provides a false but practically adequate answer: the factivity hypothesis again predicts knowledge denial, whereas the representational adequacy hypothesis predicts knowledge attribution. Across two experiments, our principal finding was that people tended to attribute knowledge for false but practically adequate answers, which supports the representational adequacy account. We propose an interpretation of existing findings that preserves a conceptual link between knowledge and truth. According to this proposal, truth is not necessary for knowledge, but it is a feature of prototypical knowledge.

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.

“Gettier cases” have played a major role in Anglo-American analytic epistemology over the past fifty years. Philosophers have grouped a bewildering array of examples under the heading “Gettier case.” Philosophers claim that these cases are obvious counterexamples to the “traditional” analysis of knowledge as justified true belief, and they treat correctly classifying the cases as a criterion for judging proposed theories of knowledge. Cognitive scientists recently began testing whether philosophers are right about these cases. It turns out that philosophers were partly right and partly wrong. Some “Gettier cases” are obvious examples of ignorance, but others are obvious examples of knowledge. It also turns out that much research in this area of philosophy is marred by experimenter bias, invented historical claims, dysfunctional categorization of examples, and mischaracterization by philosophers of their own intuitive judgments about particular cases. Despite these shortcomings, lessons learned from studying “Gettier cases” are leading to important insights about knowledge and knowledge attributions, which are central components of social cognition.

Virtue epistemologists define knowledge as true belief produced by intellectual virtue. In this paper, I review how this definition fails in three important ways. First, it fails as an account of the ordinary knowledge concept, because neither belief nor reliability is essential to knowledge ordinarily understood. Second, it fails as an account of the knowledge relation itself, insofar as that relation is operationalized in the scientific study of cognition. Third, it serves no prescriptive purpose identified up till now. An alternative theory, abilism, provides a superior account of knowledge as it is ordinarily and scientifically understood. According to abilism, knowledge is an accurate representation produced by cognitive ability.

Five experiments demonstrate the central role of knowledge attributions in social evaluations. In Experiments 1–3, we manipulated whether an agent believes, is certain of, or knows a true proposition and asked people to rate whether the agent should perform a variety of actions. We found that knowledge, more so than belief or certainty, leads people to judge that the agent should act. In Experiments 4–5, we investigated whether attributions of knowledge or certainty can explain an important finding on how people act based on statistical evidence, known as “the Wells effect”. We found that knowledge attributions, but not certainty attributions, mediate this effect on decision making. 2018 APA, all rights reserved)

This paper tests a theory about the relationship between two important topics in moral philosophy and psychology. One topic is the function of normative language, specifically claims that one “ought” to do something. Do these claims function to describe moral responsibilities, encourage specific behavior, or both? The other topic is the relationship between saying that one “ought” to do something and one’s ability to do it. In what respect, if any, does what one “ought” to do exceed what one “can” do? The theory tested here has two parts: (1) “ought” claims function to both describe responsibilities and encourage people to fulfill them (the dual-function hypothesis); (2) the two functions relate differently to ability, because the encouragement function is limited by the person’s ability, but the descriptive function is not (the interaction hypothesis). If this theory is correct, then in one respect “ought implies can” is false because people have responsibilities that exceed their abilities. But in another respect “ought implies can” is legitimate because it is not worthwhile to encourage people to do things that exceed their ability. Results from two behavioral experiments support the theory that “ought” exceeds but implies “can.” Results from a third experiment provide further evidence regarding an “ought” claim’s primary function and how contextual features can affect the interpretation of its functions.

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

Compatibilism is the view that moral responsibility is compatible with determinism. Natural compatibilism is the view that in ordinary social cognition, people are compatibilists. Researchers have recently debated whether natural compatibilism is true. This paper presents six experiments (N = 909) that advance this debate. The results provide the best evidence to date for natural compatibilism, avoiding the main methodological problems faced by previous work supporting the view. In response to simple scenarios about familiar activities, people judged that agents had moral responsibilities to perform actions that they were unable to perform (Experiment 1), were morally responsible for unavoidable outcomes (Experiment 2), were to blame for unavoidable outcomes (Experiments 3-4), deserved blame for unavoidable outcomes (Experiment 5), and should suffer consequences for unavoidable outcomes (Experiment 6). These findings advance our understanding of moral psychology and philosophical debates that depend partly on patterns in commonsense morality.

This paper connects recent findings from experimental epistemology to several major themes in classical Indian epistemology. First, current evidence supports a specific account of the ordinary knowledge concept in contemporary anglophone American culture. According to this account, known as abilism, knowledge is a true representation produced by cognitive ability. I present evidence that abilism closely approximates Nyāya epistemology’s theory of knowledge, especially that found in the Nyāya-sūtra. Second, Americans are more willing to attribute knowledge of positive facts than of negative facts, especially when such facts are inferred and even when the positive and negative “facts” are logically equivalent. Similar suspicions about knowledge of negative facts seemingly occur in classical Indian epistemology, suggesting that the asymmetry might not be an American quirk but instead reflect a cross-culturally robust tendency in knowledge attributions. Each of these themes—abilism and the positive/negative asymmetry—presents an exciting opportunity for further research in experimental cross-cultural epistemology.

Understanding science requires appreciating the values it presupposes and its social context. Both the values that scientists hold and their social context can affect scientific communication. Philosophers of science have recently begun studying scientific communication, especially as it relates to public policy. Some have proposed “guiding principles for communicating scientific findings” to promote trust and objectivity. This paper contributes to this line of research in a novel way using behavioural experimentation. We report results from three experiments testing judgments about the trustworthiness, competence and objectivity of scientists. More specifically, we tested whether such judgments are affected by three factors: consulting or not consulting nonscientists, conducting research under a restrictive or non-restrictive governmental communication policy, and the source of a lab’s funding (i.e., government funding, private funding, or a combination of the two). We found that each of these factors affects ordinary judgments of trustworthiness, competence and objectivity. These findings support several recommendations that could help improve scientific communication and communication policies.

It is widely accepted in epistemology that knowledge is factive, meaning that only truths can be known. We argue that this theory creates a skeptical challenge: because many of our beliefs are only approximately true, and therefore false, they do not count as knowledge. We consider several responses to this challenge and propose a new one. We propose easing the truth requirement on knowledge to allow approximately true, practically adequate representations to count as knowledge. In addition to addressing the skeptical challenge, this view also coheres with several previous theoretical proposals in epistemology.

We report a series of experiments examining whether people ascribe knowledge for true beliefs based on probabilistic evidence. Participants were less likely to ascribe knowledge for beliefs based on probabilistic evidence than for beliefs based on perceptual evidence or testimony providing causal information. Denial of knowledge for beliefs based on probabilistic evidence did not arise because participants viewed such beliefs as unjustified, nor because such beliefs leave open the possibility of error. These findings rule out traditional philosophical accounts for why probabilistic evidence does not produce knowledge. The experiments instead suggest that people deny knowledge because they distrust drawing conclusions about an individual based on reasoning about the population to which it belongs, a tendency previously identified by “judgment and decision making” researchers. Consistent with this, participants were more willing to ascribe knowledge for beliefs based on probabilistic evidence that is specific to a particular case. 2016 APA, all rights reserved)

From antiquity through the twentieth century, philosophers have hypothesized that, intuitively, it is harder to know negations than to know affirmations. This paper provides direct evidence for that hypothesis. In a series of studies, I found that people naturally view negations as harder to know than affirmations. Participants read simple scenarios and made judgments about truth, probability, belief, and knowledge. Participants were more likely to attribute knowledge of an outcome when framed affirmatively than when framed negatively. Participants did this even though the affirmative and negative framings were logically equivalent. The asymmetry was unique to knowledge attributions: it did not occur when participants rated truth, probability, or belief. These findings show new consequences of negation on people’s judgments and reasoning and can inform philosophical theorizing about the ordinary concept of knowledge.

Philosophers are divided on whether it is possible to intend believed-impossible outcomes. Several thought experiments in the action theory literature suggest that this is conceptually possible, though they have not been tested in ordinary social cognition. We conducted three experiments to determine whether, on the ordinary view, it is conceptually possible to intend believed-impossible outcomes. Our findings indicate that participants firmly countenance the possibility of intending believed-impossible outcomes, suggesting that it is conceptually possible to intend to do something that one believes is impossible.

We accomplish three things in this paper. First, we provide evidence that the motivational internalism/externalism debate in moral psychology could be a false dichotomy born of ambiguity. Second, we provide further evidence for a crucial distinction between two different categories of belief in folk psychology: thick belief and thin belief. Third, we demonstrate how careful attention to deep features of folk psychology can help diagnose and defuse seemingly intractable philosophical disagreement in metaethics.

A standard view in philosophy is that knowledge entails justification. Yet recent research suggests otherwise. We argue that this admirable and striking research suffers from an important limitation: participants were asked about knowledge but not justification. Thus it is possible that people attributed knowledge partly because they thought the belief was justified. Perhaps though, if given the opportunity, people would deny justification while still attributing knowledge. It is also possible that earlier findings were due to perspective taking. This paper reports further research that directly addresses these questions. Our findings support the hypothesis that knowledge entails justification on the ordinary view.

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.

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.

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.

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.

We conducted five experiments that reveal some main contours of the folk epistemology of lotteries. The folk tend to think that you don't know that your lottery ticket lost, based on the long odds ("statistical cases"); by contrast, the folk tend to think that you do know that your lottery ticket lost, based on a news report ("testimonial cases"). We evaluate three previous explanations for why people deny knowledge in statistical cases: the justification account, the chance account, and the statistical account. None of them seems to work. We then propose a new explanation of our own, the formulaic account, according to which some people deny knowledge in statistical cases due to formulaic expression.