John Turri

Philosophers have debated whether it is possible to knowledgeably infer a conclusion from a false premise. For example, if a fan believes that the actress’s dress is blue, but the dress is actually green, can the fan knowledgeably infer “the dress is not red” from “the dress is blue”? One aspect of this debate concerns what the intuitively correct verdict is about specific cases such as this. Here I report a simple behavioral experiment that helps answer this question. The main finding is that people attribute knowledge in cases where a true conclusion is inferred from a false premise. People did this despite judging that the premise was false and unknown. People also viewed the agent as inferring the conclusion from the premise. In closely matched conditions where the conclusion was false, people did not attribute knowledge of the conclusion. These results support the view that the ordinary knowledge concept includes in its extension cases of knowledge inferred from false premises.

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

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

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.

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.

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

This paper advances our understanding of the norms of assertion in two ways. First, I evaluate recent studies claiming to discredit an important earlier finding which supports the hypothesis that assertion has a factive norm. In particular, I evaluate whether it was due to stimuli mentioning that a speaker’s evidence was fallible. Second, I evaluate the hypothesis that assertion has a truth-insensitive standard of justification. In particular, I evaluate the claim that switching an assertion from true to false, while holding all else objectively constant, is irrelevant to attributions of justification. Two pre-registered experiments provide decisive evidence against each claim. In the first experiment, switching from mentioning to not mentioning fallibility made no difference to assertability attributions, thereby disproving the criticism concerning fallibility. By contrast, switching an assertion from true to false decreased the rate of assertability attribution from over 90% to less than 20%, thereby replicating and vindicating the original finding supporting a factive norm. In the second experiment, switching an assertion from true to false decreased the rate of justification attribution from over 80 to 10%, thereby undermining the hypothesis that assertion’s standard of justification is truth-insensitive. The second experiment also demonstrates that perspective-taking influences attributions of justification, and it provides initial evidence that the standard of justification for assertion is stricter than the standard for belief.

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.

Compatibilism is the view that determinism is compatible with acting freely and being morally responsible. Incompatibilism is the opposite view. It is often claimed that compatibilism or incompatibilism is a natural part of ordinary social cognition. That is, it is often claimed that patterns in our everyday social judgments reveal an implicit commitment to either compatibilism or incompatibilism. This paper reports five experiments designed to identify such patterns. The results support a nuanced hybrid account: The central tendencies in ordinary social cognition are compatibilism about moral responsibility, compatibilism about positive moral accountability, neither compatibilism nor incompatibilism about negative moral accountability, compatibilism about choice for actions with positive outcomes, and incompatibilism about choice for actions with negative or neutral outcomes.

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 introduce an account of when a rule normatively sustains a practice. My basic proposal is that a rule normatively sustains a practice when the value achieved by following the rule explains why agents continue following that rule, thus establishing and sustaining a pattern of activity. I apply this model to practices of belief management and identifies a substantive normative connection between knowledge and belief. More specifically, I proposes one special way that knowledge might set the normative standard for belief: knowing is essentially the unique way of normatively sustaining cognition and, thereby, inquiry. In this respect, my proposal can be seen as one way of elaborating a “knowledge-first” normative theory.

Assertion is fundamental to our lives as social and cognitive beings. By asserting we share knowledge, coordinate behavior, and advance collective inquiry. Accordingly, assertion is of considerable interest to cognitive scientists, social scientists, and philosophers. This paper advances our understanding of the norm of assertion. Prior evidence suggests that knowledge is the norm of assertion, a view known as “the knowledge account.” In its strongest form, the knowledge account says that knowledge is both necessary and sufficient for assertability: you should make an assertion if and only if you know that it is true. The knowledge account has been rejected on the grounds that it conflicts with our ordinary practice of evaluating assertions. This paper reports four experiments that address an important objection of this sort, which focuses on a class of examples known as “Gettier cases.” The results undermine the objection and, in the process, provide further evidence for the knowledge account. The findings also teach some important general lessons about intuitional methodology and the curation of genres of thought experiment.

I review recent empirical findings on knowledge attributions in lottery cases and report a new experiment that advances our understanding of the topic. The main novel finding is that people deny knowledge in lottery cases because of an underlying qualitative difference in how they process probabilistic information. “Outside” information is generic and pertains to a base rate within a population. “Inside” information is specific and pertains to a particular item’s propensity. When an agent receives information that 99% of all lottery tickets lose (outside information), people judge that she does not know that her ticket will lose. By contrast, when an agent receives information that her specific ticket is 99% likely to lose (inside information), people judge that she knows that her ticket will lose. Despite this difference in knowledge judgments, people rate the likelihood of her ticket losing the exact same in both cases (i.e. 99%). The results shed light on other factors affecting knowledge judgments in lottery cases, including formulaic expression and participants’ own estimation of whether it is true that the ticket will lose. The results also undermine previous hypotheses offered for knowledge denial in lottery cases, including the hypotheses that people deny knowledge because they either deny justification or acknowledge a chance for error.

I review recent work from armchair and cross-cultural epistemology on whether humans possess a knowledge concept as part of a universal “folk epistemology.” The work from armchair epistemology fails because it mischaracterizes ordinary knowledge judgments. The work from cross-cultural epistemology provides some defeasible evidence for a universal folk epistemology. I argue that recent findings from comparative psychology establish that humans possess a species-typical knowledge concept. More specifically, recent work shows that knowledge attributions are a central part of primate social cognition, used to predict others’ behavior and guide decision-making. The core primate knowledge concept is that of truth detection (across different sensory modalities) and retention (through memory) and may also include rudimentary forms of indirect truth discovery through inference. In virtue of their evolutionary heritage, humans inherited the primate social-cognitive system and thus share this core knowledge concept.

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

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

It is often thought that judgments about what we ought to do are limited by judgments about what we can do, or that “ought implies can.” We conducted eight experiments to test the link between a range of moral requirements and abilities in ordinary moral evaluations. Moral obligations were repeatedly attributed in tandem with inability, regardless of the type (Experiments 1–3), temporal duration (Experiment 5), or scope (Experiment 6) of inability. This pattern was consistently observed using a variety of moral vocabulary to probe moral judgments and was insensitive to different levels of seriousness for the consequences of inaction (Experiment 4). Judgments about moral obligation were no different for individuals who can or cannot perform physical actions, and these judgments differed from evaluations of a non-moral obligation (Experiment 7). Together these results demonstrate that commonsense morality rejects the “ought implies can” principle for moral requirements, and that judgments about moral obligation are made independently of considerations about ability. By contrast, judgments of blame were highly sensitive to considerations about ability (Experiment 8), which suggests that commonsense morality might accept a “blame implies can” principle.

I accomplish two things in this paper. I explain the motivation for including experimental research in philosophical projects on epistemic reasons and the basing relation. And I present the first experimental contributions to these projects. The results from two experiments advance our understanding of the ordinary concepts of reasons and basing and set the stage for further research on the topics. More specifically, the results support a causal theory of the basing relation, according to which reasons are causes, and a dualist theory of epistemic reasons, according to which reasons include both psychological and non-psychological items.

Leading virtue epistemologists defend the view that knowledge must proceed from intellectual virtue and they understand virtues either as refned 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 benefts of virtue epistemology and is as empirically adequate as any theory in philosophy or the social sciences could hope to be

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.

A standard view in social science and philosophy is that a lie is a dishonest assertion: to lie is to assert something that you think is false in order to deceive your audience. We report four behavioral experiments designed to evaluate some aspects of this view. Participants read short scenarios and judged several features of interest, including whether an agent lied. We found evidence that ordinary lie attributions can be influenced by aspects of audience uptake, are based on judging that the agent made an assertion (assertion attributions), and, at least in some contexts, are not based on attributions of deceptive intent. The finding on assertion attributions is predicted by the standard view, but the finding on intent attributions is not. These results help to further clarify the ordinary concept of lying and shed light on the psychological processes involved in ordinary lie attributions and related judgments.