Our folk epistemology says that if someone knows that P and tells you that P, then, given the absence of defeaters, if you believe what they tell you, you will come to know that P as well. A speaker's knowledge that P is then, for the most part, enough for a hearer to come to know that P. But there are counterexamples to this principle: testimonial knowledge does not always transfer from the speaker to the hearer. Why should that be (...) so? Because testimonial knowledge arises through the flow of information--from conclusive grounds--from the speaker through the speaker's assertion to the hearer's state of comprehension as of the speaker's assertion. A speaker's belief can be based on conclusive grounds, but the speaker's assertion may fail to provide conclusive grounds to the hearer. Then the hearer won't acquire knowledge, even from a knowledgeable speaker. Knowledge from testimony then works more like knowledge through perception. But wait, you say, that can't be so because testimony involves free will but perception does not. The essay ends with a broadly Hume inspired reply to this objection. (shrink)

We often talk about knowledge being transmitted via testimony. This suggests a picture of testimony with striking similarities to memory. For instance, it is often assumed that neither is a generative source of knowledge: while the former transmits knowledge from one speaker to another, the latter preserves beliefs from one time to another. These considerations give rise to a stronger and a weaker thesis regarding the transmission of testimonial knowledge. The stronger thesis is that each speaker in a chain of (...) testimonial transmission must know that p in order to pass this knowledge to a hearer. The weaker thesis is that at least the first speaker must know that p in order for any hearer in the chain to come to know that p via testimony. I argue that both theses are false, and hence testimony, unlike memory, can be a generative source of knowledge. (shrink)

Testimony is a vital and ubiquitous source of knowledge. Were we to refrain from accepting the testimony of others, our lives would be impoverished in startling and debilitating ways. Despite the vital role that testimony occupies in our epistemic lives, traditional epistemological theories have focused primarily on other sources, such as sense perception, memory, and reason, with relatively little attention devoted specifically to testimony. In recent years, however, the epistemic significance of testimony has been more fully appreciated. I shall here (...) focus on two questions that have received the most attention in recent work in the epistemology of testimony. First, is testimonial knowledge acquired only by being transmitted from speaker to hearer? Second, must a hearer have positive reasons to justifiedly accept a speaker's testimony? (shrink)

There is an intuitive distinction between knowing someone in a detached manner and knowing someone in a more intimate fashion — personally. The latter seems to involve the specially active participation of the person known in a way that the former does not. In this paper I present a novel, communication account of knowing someone personally that successfully explains this participation. The account also illuminates the propositional and testimonial character of the personal knowledge of persons, the conditions of limited transferability (...) to which such knowledge is subject, and its distinctly meaningful role in everyday life. I conclude by considering a worry about self-knowledge that arises on the communication account. (shrink)

I discuss several views of the nature of testimony and show how each proposal has importantly different problems. I then offer a diagnosis of the widespread disagreement regarding this topic; specifically, I argue that our concept of testimony has two different aspects to it. Inadequate views of testimony, I claim, result either from collapsing these two aspects into a single account or from a failure to recognize one of them. Finally, I develop an alternative view of testimony that captures both (...) aspects of the nature of testimony and thereby provides the basis for an illuminating theory of testimony's epistemological significance. (shrink)

In this paper, I provide the framework for an account of group assertion. On my view, there are two kinds of group assertion, coordinated and authority-based, with authority-based group assertion being the core notion. I argue against a deflationary view, according to which a group’s asserting is understood in terms of individual assertions, by showing that a group can assert a proposition even when no individual does. Instead, I argue on behalf of an inflationary view, according to which it is (...) the group itself that asserts, a conclusion supported by the fact that paradigmatic features of assertion apply only at the level of the group. A central virtue of my account is that it appreciates the important relationship that exists between most groups and their spokespersons, as well as the consequences that follow from this relationship. My view, thus, provides the framework for distinguishing when responsibility for an assertion lies at the collective level, and when it should be shouldered by an individual simply speaking for herself. (shrink)

I argue, first, that testimony is likely a natural kind (where natural kinds are accurately described by the homoeostatic property cluster theory) and that if it is indeed a natural kind, it is likely necessarily reliable. I argue, second, that the view of testimony as a natural kind and as necessarily reliable grounds a novel, naturalist global reductionism about testimonial justification and that this new reductionism is immune to a powerful objection to orthodox Humean global reductionism, the objection from the (...) too-narrow induction base. (shrink)

Testimony is a source of knowledge. A speaker asserts what a hearer may therefore come to know. Assertion has widely been treated as the exclusive or at least the paradigmatic vehicle for testimony. I argue that we testify not only by asserting something, but also by taking something for granted within some other utterance. In philosophy of language, this is called semantic presupposition. The very reasons leading theorists of testimony have for thinking that assertion can be testimony are equally reasons (...) for thinking semantic presupposition can be testimony. (shrink)

This article proposes that a general theory of assessment of historical testimony should do justice to the long tradition of adjudication in accordance with maxims of reliability and competence. I argue that an explanatory genealogical theory (along lines first adumbrated by Charles Seignobos) satisfies this condition, and that it has further notable virtues: respect for the strengths of rival theories, regard for the links between adjudication of testimony and other basic procedures of historical inquiry, and the promise of profitable lines (...) of investigation. (shrink)

This paper argues that as a name for a speech act, epistemologists typically use ‘testimony’ in a specialist sense that is more or less synonymous with ‘assertion’, but as a name for a distinctive speech act type in ordinary English, ‘testimony’ names a unique confirmative speech act type. Hence, like any good English word, ‘testimony’ has more than one sense. The paper then addresses the use of ‘testimony’ in epistemology to denote a distinctive kind of evidence: testimonial evidence. Standing views (...) of a hearer’s testimonial evidence see it as partly supervening on a speaker’s assertion that P. The paper argues for a broader account that sees a hearer’s testimonial evidence as partly supervening instead on the hearer’s representation as of a speaker meaning that P. This broader account is the comprehension view of testimonial evidence. The upshot is that not all so-called “testimony-based beliefs” are caused by a speaker’s testimony. (shrink)

Jennifer Lackey argues that “testimony” in philosophy has one sense, but that sense—the concept expressed—is disjunctive. One disjunct she calls speaker-testimony and the other disjunct she calls hearer-testimony. A speaker then testifies simpliciter iff the speaker either speaker-testifies or hearer-testifies. Inadequate views of testimony, she argues, fail to recognize, distinguish and then disjoin these two “aspects” of testimony. I argue that her view about the semantics of “testimony” is mistaken and that her criticisms of two other views—mine included —are ineffective. (...) I argue that instead of one disjunctive concept, the word “testimony” expresses more than one concept; “testimony” means many things. In ordinary English, it names two distinct kinds of constative speech acts. In epistemology, it gets used a synonym for “assertion”. In epistemology, it also refers to the process whereby we form beliefs on the basis of comprehending assertions—to communication or interlocution. (shrink)

Philosophical Quarterly 51:205, 512-26 (October 2001).

Whether or not all assertion counts as testimony (a matter not addressed here), it is argued that not all testimony involves assertion. Since many views in theepistemology of testimony assume that testimony requires assertion, such views are (at best) insufficiently general. This result also points to what we might call the epistemic significance of assertion as such.

The ability to interact in a natural language profoundly changes devices’ interfaces and potential applications of speaking technologies. Concurrently, this phenomenon challenges our mainstream theories of knowledge, such as how to analyze linguistic outputs of devices under existing anthropocentric theoretical assumptions. In section 1, I present the topic of machines that speak, connecting between Descartes and Generative AI. In section 2, I argue that accepted testimonial theories of knowledge and justification commonly reject the possibility that a speaking technological artifact can (...) give testimony. In section 3, I identify three assumptions underlying the view that rejects conversational AIs – AI-based technologies that converse, as testifiers: conversational AIs (1) lack intentions, (2) cannot be normatively assessed, and (3) cannot constitute an object in trust relations, while humans can. In section 4, I propose the concept ‘AI-testimony’ for analyzing outputs of conversational AIs, suggesting three conditions for technologies to deliver AI-testimony: (1) content is propositional, (2) generated and delivered with no other human directly involved, (3) the output is perceived as phenomenologically similar to that of a human. I conclude that this concept overcomes the limitations of the anthropocentric concept of testimony, opening future directions of research without associating conversational AIs with human-like agency. (shrink)

A epistemologia do testemunho tem reacendido forte interesse entre a classe dos atuais epistemólogos. Tem sido redescoberta a sua indispensabilidade epistêmica e reassumida a posição de que o testemunho é uma fonte de crenças penetrante e natural, no qual muitas das crenças nele fundamentadas constituem conhecimento e estão justificadas. Reducionistas e antirreducionistas se alternam, repetidamente, para explicar o papel epistêmico do testemunho na justificação da crença testemunhal, gerando um acirrado debate na epistemologia contemporânea. Advogada do Reducionismo local, Elizabeth Fricker refuta (...) a relevância da justificação com base no testemunho para crença testemunhal. Com base nisso, este artigo propõe apresentar algumas críticas aos argumentos de refutação reducionista de Fricker quanto à possibilidade epistêmica do testemunho.: The epistemology of testimony has rekindled strong reigniting interest among the train of current epistemologists. Its epistemic indispensability has been unearthed anew and the importance that the testimony is a natural and pervasive source of beliefs has been recaptured as well, considering that many of the beliefs based on itself constitute knowledge and are justified. Reductionists and Anti-Reductionists alternate, repeatedly, explaining the epistemic role of testimony in justification of testimonial belief, generating a heated debate in contemporary epistemology. Reductionism local lawyer, Elizabeth Fricker, refutes the relevance of justification with testimony-based to testimonial belief. Based on that, this paper aims at presenting some criticism to the reductive refutation of Fricker’s arguments as to the epistemic possibility of testimony. Keywords : Epistemology of testimony. Testimonial justification. Local Reductionism. Anti-Reductionism. Inferential Support. (shrink)

This paper examines several recent positions on the nature of testimony and argues that all are unsatisfactory. The first section argues against narrow, broad, and moderate views. The second section argues against Jennifer Lackey's recent analysis of testimony. Her position is supposed to avoid the problems of the prior accounts, but still suffers from two problems. After discussing those problems, this paper offers and defends an alternative analysis of testimony.

Tyler Burge famously argues in his 1993 paper "Content Preservation" that it is not only a priori true that we enjoy a prima facie warrant to take what others assert as true, but also that there our warrant to believe what we are told in certain special cases is a priori. So just as our warrant for believing certain mathematical truths might be a priori, so too there are cases of belief through testimony that are a priori. Then in a (...) 2013 Postscript to "Content Preservation" he took it all back. All of Burge's ideas and arguments for and against are interesting and important, and deepen our understanding of testimony, comprehension, warrant, and the a priori. But his ideas and arguments are hard to understand. This paper explains all of ideas and arguments, both for and against, in a clear and comprehensive way. Along the way, Anna-Sara Malmgren's interpretation and criticism of Burge's position is also expounded and criticized. (shrink)

This chapter states the contrast between presumptivism about testimonial warrant (often called anti-reductionism) and strict reductionism (associated with Hume) about testimonial warrant. Presumptivism sees an analogy with modest foundationalism about perceptual warrant. Strict reductionism denies this analogy. Two theoretical frameworks for these positions are introduced to better formulate the most popular version of persumptivism, a competence reliabilist account. Seven arguments against presumptivism are then stated and critiqued: (1) The argument from reliability; (2) The argument from reasons; (3) the argument from (...) positive reasons; (4) the argument from negative reasons; (5) the argument from agency; (6) the argument from psychological force; and (7) the argument from gullibility. If presumptivm is false, it is not for any of these arguments. (shrink)

Everyday life reasoning and argumentation is defeasible and uncertain. I present a probability logic framework to rationally reconstruct everyday life reasoning and argumentation. Coherence in the sense of de Finetti is used as the basic rationality norm. I discuss two basic classes of approaches to construct measures of argument strength. The first class imposes a probabilistic relation between the premises and the conclusion. The second class imposes a deductive relation. I argue for the second class, as the first class is (...) problematic if the arguments involve conditionals. I present a measure of argument strength that allows for dealing explicitly with uncertain conditionals in the premise set. (shrink)

I propose that testimony is subject to a norm that is backed by a credibility sanction: whenever the norm is violated, it is appropriate for the testifier to lose some credibility for their future testimony. This is one of a family of sanction-based norms, where violation of the norm makes it appropriate to lose some power; in this case, the power to induce belief through testimony. The applicability of the credibility norm to testimony follows from the epistemology of testimony, in (...) that false or unjustified testimony weakens the reason for belief that is provided by the speaker's future testimony. (shrink)

Social knowledge, for the most part, is knowledge through testimony. This essay is an overview of the epistemology of testimony. The essay separates knowledge from justification, characterizes testimony as a source of belief, explains why testimony is a source of knowledge, canvasses arguments for anti-reductionism and for reductionism in the reductionism vs. anti-reductionism debate, addresses counterexamples to knowledge transmission, defends a safe basis account of testimonial knowledge, and turns to social norms as a partial explanation for the reliability of testimony.

Extended Rationality: A Hinge Epistemology provides a novel account of the structure of epistemic justification. Its central claim builds upon Wittgenstein's idea in On Certainty that epistemic justifications hinge on some basic assumptions and that epistemic rationality extends to these very hinges. It exploits these ideas to address major problems in epistemology, such as the nature of perceptual justifications, external world skepticism, epistemic relativism, the epistemic status of basic logical laws, of the Principle of the Uniformity of Nature, of our (...) belief in the existence of the past and of other minds, and the nature of testimonial justification. Along the way, further technical issues, such as the scope of the Principle of Closure of epistemic operators under known entailment, the notion of transmission failure, and the existence of entitlements are addressed in new and illuminating ways. (shrink)

Many contributors of the debate about knowledge by testimony concentrate on the problem of justification. In my paper I will stress a different point – the concept of testimony itself. As a starting point I will use the definitional proposal of Jennifer Lackey. She holds that the concept of testimony should be regarded as entailing two aspects – one corresponding to the speaker, the other one to the hearer. I will adopt the assumption that we need to deal with both (...) aspects. Nevertheless, I will show that her concept – which suggests regarding testimony as an act of communication conveying information – is too broad and, therefore, I will end up with a different twofold definition. (shrink)

In comparison to other epistemic sources (perception, memory and reason) testimony is the only one dealing with the social aspects of gaining and justifying knowledge. One main problem of the current discussion about knowledge by testimony is the concept of testimony itself. It is quite unclear what the correct notion of testimony is supposed to be. In this essay I present a proposal to define the concept of testimony in making a distinction between the conditions which hold in the speaker’s (...) context and the ones necessary and sufficient for the hearer. Furthermore, I will briefly defend the thesis that there is not one general concept of testimony, but that there are different ones connected via a kind of specialisation relation. (shrink)

When is a testimony-based belief justified? According to so-called "Anti-Reductionism," the principle that a hearer is prima facie justified to take what another tells them at face value is true. I call this position "Liberal Foundationalism." I call it "liberal" for it is more liberal than "Moderate Foundationalism" that holds that perception-based beliefs are prima facie justified but testimony-based beliefs are not. Liberal Foundationalism has two interpretations: the principle is a contingent empirical truth, or an a priori necessary truth. I (...) call the view that the principle is a priori necessary "Liberal Fundamentalism." This chapter defends Liberal Fundamentalism against objections in the first half, and then in the second half it introduces "Weak Liberal Fundamentalism," the view that it is a priori necessary that testimony provides some epistemic support, but perhaps not enough, absent defeat, for knowledge. In later work I abandon the view that the principle is a priori necessary, but I still maintain the distinction between Strong and Weak variants of the principle, and the replies to many of the objections to the principle. (shrink)

According to the Acceptance Principle, a person is entitled to accept a proposition that is presented as true (asserted) and that is intelligible to him or her, unless there are stronger reasons not to. Burge assumes this Principle and then argues that it has an apriori justification, basis or rationale. This paper expounds Burge's teleological reliability framework and the details of his a priori justification for the Principle. It then raises three significant doubts.

Let us focus on what I take it is the paradigm case of testimony—the intentional transfer of a belief from one agent to another, whether in the usual way via a verbal assertion made by the one agent to the other, or by some other means, such as through a note.1 So, for example, John says to Mary that the house is on fire (or, if you like, ‘texts’ her this message on her phone), and Mary, upon hearing this, forms (...) the belief that the house is on fire and consequently exits the building at speed. Clearly, a great deal of our beliefs are gained via testimony, and if the epistemic status of our testimonybased beliefs were to be called into question en masse, then this would present us with quite a predicament. It is thus essential that we have some plausible account of the epistemology of testimony. Our primary focus will be on the justification for our testimony-based beliefs, though along the way we will say a little about other relevant epistemic notions like epistemic entitlement as well. (shrink)

In debates about trust and testimony, epistemologists have traditionally been divided into two groups: those who hold that accepting the testimony of other people should be a kind of credulity without evidence (anti-reductivism) and those who assert that we shouldn't recognize any testimony as true or justified without appropriate evidence (reductivism). I will argue in favour of the evidentialist position about trust, or the stance that epistemically responsible trust is a matter of evidence, but also in favour of the thesis (...) that the position assumed by anti-reductivists is not necessarily an anti-evidentialist position. The crucial difference between anti-reductivism and reductivism does not pertain to the question of evidence, but to epistemic agency. Finally, I will argue against anti-reductivism and in favour of agency evidentialism, wherein it is assumed that accepting testimony is a kind of agency where our (reflective) control is strong enough to ensure that our trust is responsible. The version of agency evidentialism which I here support presumes: (i) doxastic voluntarism, or the existence of intellectual freedom in the sense that we have to be capable of certain intellectual choices or decisions, and (ii) virtue epistemology, or the normative approach according to which the target of epistemic evaluation is an epistemic agent to whom we ascribe epistemic or intellectual virtues or vices (epistemic responsibility, epistemic conscientiousness or like.). (shrink)

In this paper, I offer a contribution to the debate on testimony that rests on three elements: the definition of semantic information, the analysis of trust as a second?order property of first?order relations, and Floridi?s Network Theory of Account (NTA). I argue that testimony transmits semantic information and it is neither grounded on trust nor justified by it. Instead, I show that testimony is an occurrence of a first?order relation of communication affected by the second?order property of trust. I then (...) defend the view that an epistemic agent can acquire some knowledge, on the basis of the information communicated through testimony, if and only if the agent is able to connect the transmitted information to the conceptual network of interrelation to which it belongs. I refer to Floridi?s NTA to show how such a network allows the epistemic agent to achieve knowledge on the basis of semantic information. (shrink)

Testimony is an indispensable source of information. Yet, contrary to ‘literalism’, speakers rarely mean just what they say; and even when they do, that itself is something the hearer needs to realize. So, understanding instances of testimony requires more than merely reading others' messages off of the words they utter. Further, a very familiar and theoretically well-entrenched approach to how we arrive at such understanding serves to emphasize, not merely how deeply committed we are to testimony as a reliable source (...) of information, but that epistemological questions about testimonial belief are – perhaps even must be – posterior to such a commitment. This result does not itself dictate any particular views on the epistemology of testimony. However, not only does the failure of literalism not support the view that the justificatory basis of testimony-based beliefs is importantly inferential; it in fact undermines a key premise in one important argument for the view that one needs independent, positive reasons for accepting a given testimonial report. More generally, the present paper illustrates how discussions of the epistemology of testimony might usefully interact with an examination of the epistemology of understanding. (shrink)

There is a growing interest in the foundations as well as the application of imprecise probability in contemporary epistemology. This dissertation is concerned with the application. In particular, the research presented concerns ways in which imprecise probability, i.e. sets of probability measures, may helpfully address certain philosophical problems pertaining to rational belief. The issues I consider are disagreement among epistemic peers, complete ignorance, and inductive reasoning with imprecise priors. For each of these topics, it is assumed that belief can be (...) modeled with imprecise probability, and thus there is a non-classical solution to be given to each problem. I argue that this is the case for peer disagreement and complete ignorance. However, I discovered that the approach has its shortcomings, too, specifically in regard to inductive reasoning with imprecise priors. Nevertheless, the dissertation ultimately illustrates that imprecise probability as a model of rational belief has a lot of promise, but one should be aware of its limitations also. (shrink)

This dissertation addresses the following questions: How should epistemologists conceptualize testimony? What do people use testimony to do? And why does ‘what people do’ with testimony matter epistemically? In response to these questions I both define and characterize testimony. While doing so I argue for the following answers, given here very briefly: What do people do when they testify? They tell each other things and avow that those things are true, offering their statements to others as reasons to believe. More (...) importantly, they interact with each other in order to negotiate about significance. Why do these activities matter epistemically? Because by engaging in them people generate understanding, as well as knowledge, that no one involved may have had prior to negotiation. Not only that, but they generate collective hermeneutic resources—conceptual tools with which to interpret and understand. In so doing, they not only learn, they create significance and (re)construct social worlds, living together as epistemic, moral, and political agents. So, how should epistemologists conceptualize testimony? They should treat it as a particular speech act that most often occurs as part of a testimonial exchange—an interactive, interpretive, dialogical activity that people use in order to negotiate about significance and generate understanding. This characterization of testimony is an important contribution because it: reveals some of the distinctively social aspects of testimonial knowledge and understanding; suggests better answers to epistemic questions about testimony than those based on typical characterizations in the literature; leads discussion on the topic in a number of new directions; and it lays a foundation for an ethics of testimony that cannot be separated from epistemic concerns. Neither can those concerns be separated from social, moral, and political considerations. The position thus pushes epistemologists to investigate the intertwining of epistemic, moral, and political agency. (shrink)

This paper introduces a multi-modal polymorphic type theory to model epistemic processes characterized by trust, defined as a second-order relation affecting the communication process between sources and a receiver. In this language, a set of senders is expressed by a modal prioritized context, whereas the receiver is formulated in terms of a contextually derived modal judgement. Introduction and elimination rules for modalities are based on the polymorphism of terms in the language. This leads to a multi-modal non-homogeneous version of a (...) type theory, in which we show the embedding of the modal operators into standard group knowledge operators. (shrink)

Temeljni je cilj ovog rada primjena općenite ideje evidencijalizma na poseban slučaj svjedočanstva i povjerenja koje određujem kao postupak prihvaćanja iskaza drugih ljudi. U prvom dijelu, zagovaram poziciju evidencijalizma u pogledu povjerenja, odnosno stav da je epistemički odgovorno povjerenje stvar posjedovanja odgovarajuće evidencije ili epistemičkih razloga. U drugom dijelu, razmatram primjedbe koje mogu biti upućene ovoj poziciji od strane anti redukcionista i nihilista. Konačno, u trećem dijelu nastojim braniti evidencijalizam protiv upućenih kritika, te predlažem kriterij primjerene evidencije za epistemički odgovorno (...) povjerenje.The main purpose of this paper is to apply the general idea of evidentialism to the very specific case of testimony and trust characterized as being the procedure of acceptance the other people reports. In the first part, I argue in favour of evidentialism concerning trust, a viewpoint that takes epistemically responsible trust as a matter of evidence. In the second part, I analyze the objections that can be put on this kind of evidentialism by anti-reductionism and nihilism. In the third part, I try to defend evidentialism against this critique and I propose the evidential standard of epistemically responsible trust. (shrink)