Recent work in philosophy and cognitive science shows that knowledge is the norm of our social practice of assertion, in the sense that an assertion should express knowledge. But why should an assertion express knowledge? I hypothesize that an assertion should express knowledge because the point of assertion is to transmit knowledge. I present evidence supporting this hypothesis.

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. (shrink)

Evidence from life science, cognitive science, and philosophy supports the hypothesis that knowledge is a central norm of the human practice of assertion. However, to date, the experimental evidence supporting this hypothesis is limited to American anglophones. If the hypothesis is correct, then such findings will not be limited to one language or culture. Instead, we should find a strong connection between knowledge and assertability across human languages and cultures. To begin testing this prediction, we conducted three experiments on Koreans (...) in Korean. In each case, the findings replicated prior results observed in Americans and were corroborated by key findings from new replication studies on Americans using materials back-translated from Korean. These findings support the theory that there is a core, cross-culturally robust human practice of assertion and that, according to the rules of this practice, assertions should express knowledge. (shrink)

Researchers recently demonstrated a strong direct relationship between judgments about what a person knows and judgments about how a person should act. But it remains unknown whether actionability judgments cause knowledge judgments, or knowledge judgments cause actionability judgments. This paper uses causal modeling to help answer this question. Across two experiments, we found evidence that actionability judgments cause knowledge judgments.

Several studies have found a robust effect of truth on epistemic evaluation of belief, decision, action and assertion. Thus, truth has a significant effect on normative participant evaluations. Some theorists take this truth effect to motivate factive epistemic norms of belief, action, assertion etc. In contrast, I argue that the truth effect is best understood as an epistemic instance of the familiar and ubiquitous phenomenon of outcome bias. I support this diagnosis from three interrelating perspectives: (1) by epistemological theorizing, (2) (...) by considerations from cognitive psychology and (3) by methodological reflections on the relationship between folk epistemology and epistemological theorizing. (shrink)

Assertions are speech acts by means of which we express beliefs. As such they are at the heart of our linguistic and social practices. Recent research has focused extensively on the question whether the speech act of assertion is governed by norms, and if so, under what conditions it is acceptable to make an assertion. Standard theories propose, for instance, that one should only assert that p if one knows that p (the knowledge account), or that one should only assert (...) that p if p is true (the truth account). In a series of four experiments, this question is addressed empirically. Contrary to previous findings, knowledge turns out to be a poor predictor of assertability, and the norm of assertion is not factive either. The studies here presented provide empirical evidence in favour of the view that a speaker is warranted to assert that p only if her belief that p is justified. (shrink)

Assertions are our standard communicative tool for sharing and acquiring information. Recent empirical studies seemingly provide converging evidence that assertions are subject to a factive norm: you are entitled to assert a proposition p only if p is true. All these studies, however, assume that we can treat participants' judgments about what an agent 'should say' as evidence of their intuitions about assertability. This paper argues that this assumption is incorrect, so that the conclusions drawn in these studies are unwarranted. (...) It shows that most people do not interpret statements about what an agent 'should say' as statements about assertability, but rather as statements about what is in the agent's interest to do. It identifies some effective measures to force the intended reading of statements about what an agent 'should say', and shows that when these measures are implemented, people's judgments consistently and overwhelmingly align with non-factive accounts of assertion. (shrink)