Communication is essential to human society, and assertion is central to communication. This article reviews evidence from life science, cognitive science, and philosophy relevant to understanding how our social practice of assertion is structured and sustained. The principal conclusion supported by this body of evidence is that knowledge is a central norm of assertion—that is, according to the rules of the practice, assertions should express knowledge.

Assertions are the centre of gravity in social epistemology. They are the vehicles we use to exchange information within scientific groups and society as a whole. It is therefore essential to determine under which conditions we are permitted to make an assertion. In this paper we argue and provide empirical evidence for the view that the norm of assertion is justified belief: truth or even knowledge are not required. Our results challenge the knowledge account advocated by, e.g. Williamson (1996), in (...) general, and more specifically, put into question several studies conducted by Turri (2013, 2016) that support a knowledge norm of assertion. Instead, the justified belief account championed by, e.g. Douven (2006), seems to prevail. (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)

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)

Research on children's developing moral cognition has mostly focused on their evaluation of, and reasoning about, others' intrinsically harmful (non-)verbal actions (e.g., hitting, lying). But assertions may have morally relevant (intended or unintended) consequences, too. For instance, if someone wrongly claims that “This water is clean!”, such an incorrect representation of reality may have harmful consequences to others. In two experiments, we investigated preschoolers' evaluation of others' morally relevant factual claims. In Experiment 1, children witnessed a puppet making incorrect assertions (...) that would lead to harm or to no harm. In Experiment 2, incorrect assertions would always lead to harm, but the puppet either intended the harm to occur or not. Children evaluated the puppet’s factual claim more negatively when they anticipated harmful versus harmless consequences (Experiment 1) and when the puppet’s intention was bad versus good over and above harmful consequences (Experiment 2). These findings suggest that preschoolers’ normative understanding is not limited to evaluating others’ intrinsically harmful transgressions, but also entails an appreciation of the morally relevant consequences of, and intentions underlying, others’ factual claims. (shrink)