Discussion of the phenomena of post-truth and fake news often implicates the closed epistemic networks of social media. The recent conversation has, however, blurred two distinct social epistemic phenomena. An epistemic bubble is a social epistemic structure in which other relevant voices have been left out, perhaps accidentally. An echo chamber is a social epistemic structure from which other relevant voices have been actively excluded and discredited. Members of epistemic bubbles lack exposure to relevant information and arguments. Members of echo chambers, on the other hand, have been brought to systematically distrust all outside sources. In epistemic bubbles, other voices are not heard; in echo chambers, other voices are actively undermined. It is crucial to keep these phenomena distinct. First, echo chambers can explain the post-truth phenomena in a way that epistemic bubbles cannot. Second, each type of structure requires a distinct intervention. Mere exposure to evidence can shatter an epistemic bubble, but may actually reinforce an echo chamber. Finally, echo chambers are much harder to escape. Once in their grip, an agent may act with epistemic virtue, but social context will pervert those actions. Escape from an echo chamber may require a radical rebooting of one's belief system.

In this paper, I offer an account of propositional learning: namely, learning that p. I argue for what I call the “Three Transitions Thesis” or “TTT” according to which four states and three transitions between them characterize such learning. I later supplement the TTT to account for learning why p. In making my case, I discuss mathematical propositions such as Fermat's Last Theorem and the ABC Conjecture, and then generalize to other mathematical propositions and to non-mathematical propositions. I also discuss some interesting applications of the TTT, and reply to some noteworthy objections.

Michael Burroughs and Deborah Tollefsen (2016) claim that children are subject to widespread testimonial injustice. They argue that empirical data shows that children are prejudicially accorded less epistemic credibility in forensic contexts, and that this in turn shows that the same is true in broader contexts. While I agree that there is indeed testimonial injustice against children, I argue that Burroughs and Tollefsen exaggerate its severity and extent, by exaggerating children's testimonial reliability. Firstly, the empirical data do not quite support their claim about children's performance in forensic contexts. Secondly, while they advocate a relational conception of children's agency which emphasizes the role of adults in realizing their testimonial abilities, Burroughs and Tollefsen miss the full implications of such a conception for our evaluation of children's credibility, and for our behavior towards them in testimonial contexts. Thirdly, they underestimate the significance of children's limited general knowledge.

Pluralistic ignorance is a social-psychological phenomenon in which an agent believes that their attitudes, feelings, and beliefs are different from those of others, despite the fact that their public behavior is identical. I argue that agents in standard cases of pluralistic ignorance are epistemically irrational. I accomplish this, first, by rebutting a recent argument for the rationality of pluralistic ignorance. Next, I offer a defeat-based argument against the epistemic rationality of pluralistic ignorance. Third, I examine a type of case in which the pluralistically ignorant agent's belief is irrational, despite the fact that this belief lacks a defeater. Finally, I consider instances of pluralistically ignorant agents whose beliefs are not irrational, but explain why such cases are not problematic for my main thesis. This critical discussion allows me to offer an important amendment to an extant account of pluralistic ignorance.

The ambiguity theory of ‘knows’ is the view that ‘knows’ and its cognates have more than one sense, and that which sense of ‘knows’ is used in a knowledge ascription or denial determines, in part, the meaning (and as a result the truth conditions) of that knowledge ascription or denial. In this paper, I argue that the ambiguity theory of ‘knows’ ought to be taken seriously by those drawn to epistemic contextualism. In doing so I first argue that the ambiguity theory of ‘knows’ is a distinct view from epistemic contextualism. Second, I provide independent philosophical and linguistic considerations to motivate the ambiguity theory. Third, I argue that the ambiguity theory has the same central, generally agreed upon virtues ascribed to epistemic contextualism (namely, the ability to solve certain persistent epistemological problems relating to skeptical arguments and the ability to preserve the truth of most of our everyday, ordinary usages of ‘knows’ and its cognates). Finally, I provide an ambiguity-theory-friendly account of why contextualism may be initially appealing, and why this shouldn't dissuade us from taking the ambiguity theory seriously nonetheless.

Under which conditions are we epistemically justified to believe that what other people tell us is true? Traditionally, the answer has either been reductionist or anti-reductionist: Either our justification reduces to non-testimonial reasons, or we have a presumptive, though defeasible, right to believe what we are told. However, different cases pull in different directions. Intuitively, someone asking for the time is subject to different epistemic standards than a surgeon consulting a colleague before a dangerous operation. Following this line of thought, this paper develops an account of testimonial justification that captures our reductionist as well as our anti-reductionist intuitions. It is argued that the speaker's commitment to an epistemic norm, as well as the hearer's understanding of that norm, gives the hearer a presumptive right to believe what she is told. However, this justification doesn't apply to situations with high practical risks. Here, the hearer needs reductive reasons to believe that her interlocutor is especially qualified to give her the desired information.

It is a familiar criticism of Subject-Sensitive Invariantism that the view makes incorrect predictions about cases in which the attributor of knowledge is in a high-stakes situation and the subject of the attribution in a low-stakes situation. In a recent paper in this journal, Brian Kim has argued that the mentioned type of case should be ignored, since the relevant knowledge ascriptions are inappropriate in virtue of violating an epistemic norm of presupposing. I show, pace Kim, that the mentioned utterances do not carry factivity presuppositions. To this end I discuss a phenomenon known as presupposition suspension, which is widely associated with the presuppositions of epistemic factives such as know that p or discover that p. I argue further that the problem of unknown presuppositions discussed by Kim can be circumvented by slightly amending the cases at hand. In particular, I demonstrate that factivity presuppositions are unobjectionable in problem cases in which the high-stakes ascriber knows the presuppositions at issue to be true.

Eyewitnesses are susceptible to recollecting that they experienced an event in a way that is consistent with false information provided to them after the event. The effect is commonly called the misinformation effect. Because jurors tend to find eyewitness testimony compelling and persuasive, it is argued that jurors are likely to give inappropriate credence to eyewitness testimony, judging it to be reliable when it is not. It is argued that jurors should be informed about psychological findings on the misinformation effect, to ensure that they lower the credence that they give to eyewitness testimony to reflect the unreliability of human memory that is demonstrated by the effect. Here I present a new argument, the overcritical juror argument, to support the conclusion that eyewitnesses are likely to make inappropriate credence assignments to eyewitness testimony. Whereas previously authors have argued that jurors will tend to give too much credence to eyewitness testimony, I identify circumstances in which jurors will give too little credence to some pieces of testimony. In my view jurors should be informed by psychological findings relating to the misinformation effect to ensure that they do not lower the credence that they give to eyewitness testimony when they should not.