John Turri

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.

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.

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.

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.

In this essay I show how to reconcile epistemic invariantism with the knowledge account of assertion. My basic proposal is that we can comfortably combine invariantism with the knowledge account of assertion by endorsing contextualism about speech acts. My demonstration takes place against the backdrop of recent contextualist attempts to usurp the knowledge account of assertion, most notably Keith DeRose's influential argument that the knowledge account of assertion spells doom for invariantism and enables contextualism's ascendancy

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.

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.

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.

I report two experiments studying the relationship among explicit judgments about what people see, know, and should assert. When an object of interest was surrounded by visibly similar items, it diminished people’s willingness to judge that an agent sees, knows, and should tell others that it is present. This supports the claim, made by many philosophers, that inhabiting a misleading environment intuitively decreases our willingness to attribute perception and knowledge. However, contrary to stronger claims made by some philosophers, inhabiting a misleading environment does not lead to the opposite pattern whereby people deny perception and knowledge. Causal modeling suggests a specific psychological model of how explicit judgments about perception, knowledge, and assertability are made: knowledge attributions cause perception attributions, which in turn cause assertability attributions. These findings advance understanding of how these three important judgments are made, provide new evidence that knowledge is the norm of assertion, and highlight some important subtleties in folk epistemology.

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

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

Epistemic reasons are mental states. They are not propositions or non-mental facts. The discussion proceeds as follows. Section 1 introduces the topic. Section 2 gives two concrete examples of how our topic directly affects the internalism/externalism debate in normative epistemology. Section 3 responds to an argument against the view that reasons are mental states. Section 4 presents two problems for the view that reasons are propositions. Section 5 presents two problems for the view that reasons are non-mental facts. Section 6 argues that reasons are mental states. Section 7 responds to objections.