Knowledge Tree
testimony
synthesized from dimensionsTestimony is a fundamental epistemic interaction in which one agent communicates information to another, who then relies on that communication as a basis for belief. While traditionally associated with human speech, the concept is broadly defined to encompass various media—including text, digital outlets, and, increasingly, machine-generated content—where an agent presents a proposition as true. As a primary source of knowledge, testimony is essential to the structure of human culture, enabling the transmission of information across generations and social networks in ways that transcend the limits of individual perception, memory, and reason.
A central debate in social epistemology concerns the justification of testimonial belief, specifically whether testimony is a "basic" source of knowledge or one that requires external validation. Reductionists, following a tradition associated with David Hume, argue that a hearer is only justified in accepting testimony if they possess independent, inductive evidence of the speaker’s reliability. This position is motivated by a desire to avoid gullibility and the potential for deception. Conversely, non-reductionists, such as Thomas Reid, contend that testimony is a basic source of justification, positing that humans possess an innate, *a priori* entitlement to trust intelligible testimony unless there is an "undefeated defeater"—evidence that the specific report is false or the source is unreliable.
The discourse also distinguishes between the transmission and generation of knowledge. Preservationists, such as Michael Dummett and Jennifer Lackey, argue that testimony primarily serves to transmit knowledge from a speaker to a hearer, often requiring that the speaker themselves possess knowledge of the proposition. Critics of this view, however, point to cases where a hearer may acquire knowledge even when the speaker lacks it, provided the information is reliable or corrected by other mechanisms. This has led to the development of hybrid models that attempt to reconcile the speaker’s role as an epistemic agent with the hearer’s responsibility to evaluate the credibility of the information received.
The relationship between testimony and other cognitive faculties is a subject of ongoing inquiry. Some theorists advocate for "epistemic parity," suggesting that testimony, memory, and perception share a similar epistemic structure. Others emphasize the unique interpersonal nature of testimony, noting that it often involves an "act of assurance" where the speaker takes personal responsibility for the truth of their claim. This interpersonal dynamic distinguishes testimony from purely observational sources, as it introduces social and ethical dimensions, such as the potential for testimonial injustice—where individuals are unfairly denied credibility due to identity-based prejudices.
Ultimately, the study of testimony is significant for both theoretical and practical domains. It informs our understanding of historiography, the verification of religious and scientific traditions, and the assessment of contemporary information ecosystems like Wikipedia. As technology evolves, the field continues to grapple with the status of automated systems and AI, questioning whether non-conscious entities can function as testifiers. Despite these complexities, testimony remains an indispensable mechanism for navigating the world, as it allows individuals to extend their epistemic reach far beyond their own direct experiences.
Model Perspectives (14)
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In epistemology, testimony is defined as the act of one person communicating information to another, encompassing diverse media such as speech, text, books, and digital outlets [34, 15, 7]. While some scholars treat it as a fundamental source of knowledge alongside perception, memory, and reason [5, 14, 22], testimony is distinct because it lacks a dedicated cognitive faculty; instead, it involves acquiring knowledge of a proposition because someone else has stated it [6, 38, 55].
A central debate in social epistemology concerns the burden of justification placed on the recipient of testimony [30, 41]. Reductionists, historically associated with David Hume, argue that testimonial justification is not basic but derivative, requiring individuals to infer the reliability of a source from past observations of their veracity [26, 43, 45]. Conversely, anti-reductionists, such as Thomas Reid, posit that humans possess an innate, non-inferential tendency to trust testimony [10, 44, 46], often arguing that the epistemology of testimony should mirror that of perception or memory [26, 51, 50].
Critics of the anti-reductionist view, including Paul Faulkner and Jennifer Lackey, argue that testimony imposes higher epistemic demands than perception because human testifiers possess the capacity for deception or voluntary misrepresentation, a factor absent in the physical environment [56, 57, 58]. Despite such concerns, Reliabilists maintain that testimony remains a valid source of knowledge provided the information originates from a reliable source [1, 9, 2]. This has led to various strategies for managing testimonial risk, such as the "track record" approach or the scrutiny of reports against other evidence [11, 39]. The significance of this field extends to practical domains, including historiography, the verification of religious traditions like the hadith [29], and the assessment of contemporary information sources like Wikipedia [40].
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Testimony is a primary subject of debate in epistemology, centered on whether it functions as a basic source of knowledge or requires external justification. Epistemologists like Galen Strawson and Robert Audi argue that testimony is operationally dependent on perception, as one must perceive a speaker to receive their testimony employment of perception and memory, testimony operationally dependent on perception. While Alvin Plantinga and Robert Audi suggest testimony is distinct because it is "defeatable" by other evidence testimony differs from perception, Peter Graham counters that this does not imply testimony is inferior or lacks direct justification fact that one source defeats another.
A significant divide exists between "reductionists" and "liberals." Reductionists often seek an inductive basis for the reliability of testimony; however, critics like Coady and James Van Cleve note that much of this "corroboration" is itself testimonial corroboration relies on other testimony. Tomoji Shogenji proposes that the ubiquity of testimony creates a cumulative effect that provides tacit confirmation of its reliability ubiquity of testimonially-based beliefs. Conversely, Tyler Burge argues for an *a priori* entitlement to accept intelligible testimony subject is a priori entitled, a view criticized by those who argue he assumes properly functioning rational faculties critics of Tyler Burge's argument.
Finally, some theorists, such as Christopher Green, advocate for "epistemic parity," arguing that testimony, memory, and perception share a similar epistemic structure epistemic parity between testimony, memory. This includes the idea that a testifier acts as an epistemic agent or employee for the recipient testifier acts as an epistemic agent. Others, such as Hinchman and Moran, emphasize the "act of assurance" in testimony, suggesting that the speaker takes personal responsibility for the truth of the proposition, which alters the epistemic dynamics between the speaker and the recipient epistemic responsibilities of the recipient.
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Testimony is defined as an epistemic interaction where one individual communicates information to another, who then relies on their word an epistemic interaction where individuals communicate. A central puzzle in epistemology is determining why this process functions as a valid source of knowledge the epistemological puzzle regarding testimony.
Philosophical debate centers on whether testimony is a basic source of knowledge or a composite process involving perception and inference a philosophical debate regarding whether testimony. Knowledge-preservationists, such as Michael Dummett, argue that testimony does not create knowledge but merely preserves and transmits it from one person to another, analogous to memory testimony should not be regarded as a source. This perspective asserts that a hearer can only gain knowledge if the speaker also knows the proposition thesis that a subject's testimonially-based knowledge. Critics like Jennifer Lackey challenge this, providing counterexamples where hearers gain knowledge from reliable testimony even when the speaker lacks knowledge or belief a biology teacher who does not believe in evolution. Defenders of preservationism respond to such cases by denying the speaker’s ignorance, the hearer’s knowledge, or the classification of the interaction as testimony defenders of knowledge-preservationism can respond.
Beyond pure transmission, testimony is also analyzed in social and political contexts. Miranda Fricker and Kristie Dotson highlight how identity-based prejudices can lead to testimonial injustice, where speakers are silenced or rendered less credible due to societal power dynamics Miranda Fricker defines testimonial injustice. Additionally, the rise of automated systems has introduced the concept of machine testimony, prompting debate over whether non-conscious entities can be considered 'testifiers' machine testimony should be classified as testimony.
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In social epistemology, testimony is broadly defined as an act where an agent communicates to an audience that a proposition is true [15, 52]. This field, which gained significant prominence through the work of scholars like C.A.J. Coady, Elizabeth Fricker, and Edward Craig, examines whether testimony serves as a basic source of knowledge or requires further justification [60].
The central debate regarding testimonial justification is divided between reductionism and anti-reductionism. Reductionists argue that testimony-based beliefs are only justified if the audience possesses independent, inductive evidence for the speaker's reliability, often derived from observation or memory [17, 29, 30]. Conversely, anti-reductionists (or non-reductionists) contend that testimony is a basic source of justification, meaning a belief is justified provided there are no reasons for doubt [18, 54]. Critics, such as Miranda Fricker, argue that non-reductionism may license gullibility, though proponents maintain that monitoring for trustworthiness can occur automatically [36].
Beyond individual justification, conceptualizations of testimony vary. Some philosophers, including Moran (2006) and Watson (2004), liken testifying to a promise, where the speaker offers an assurance of truth [1]. Others, like C.A.J. Coady, emphasize the speaker's competence and the relevance of the information to an unresolved question [3]. Recent scholarship has expanded these inquiries into new domains, such as the role of technology in multi-author platforms like Wikipedia and the debated question of whether AI-generated content constitutes testimony [21]. Furthermore, formal epistemology utilizes proof-based methods to address how groups aggregate judgments and how individuals should update their beliefs based on the testimony of others [24, 25].
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Testimony is broadly defined as any instance where one person communicates information to another, extending beyond formal courtroom settings general definition of testimony. Epistemologically, it is recognized as an indispensable source of knowledge for history, science, and social interaction indispensable source of knowledge, yet its nature as a source of justification remains a subject of intense philosophical debate epistemological source debate.
A central divide exists between Reductionism and Non-reductionism. Reductionists, such as those following the tradition of David Hume, argue that for a listener to be justified in accepting testimony, they must possess non-testimonial positive reasons to believe the speaker is reliable reductionist justification condition. This is often motivated by a desire to avoid gullibility concern regarding gullibility. Conversely, Non-reductionists, such as Thomas Reid, argue that testimony is a basic source of justification, relying on an innate faculty rather than needing to be reduced to perception or inference Reid's innate faculty theory.
Further debate categorizes these views as Liberal or Conservative liberal versus conservative classification. Liberals, like Tyler Burge, contend that individuals are a priori entitled to accept intelligible testimony entitlement to accept testimony, whereas Conservatives, including Jennifer Lackey, demand positive reasons for trust Lackey's conservative argument. These views also diverge on whether testimony is a direct input to a cognitive faculty (non-inferentialism) direct cognitive input or requires a multi-step inferential process inferentialist four-step model. Critics of reductionist models argue that the requirement for independent verification often leads to an impossible epistemic regress regress or circularity problem.
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Testimony is a central subject in social epistemology, defined by Thomas Reid (1785) as an epistemic subject relying on a speaker's authority for the truth of a proposition relying on authority. Scholars debate whether testimony is a basic source of justification, with some arguing that its epistemic status mirrors that of perception Thomas Reid (1983).
Epistemological discourse on testimony focuses on three core questions: how hearers are justified in believing a speaker, whether testimony can generate or merely transmit knowledge, and the source of evidence for testimonial beliefs Third Big Question. Regarding justification, Reductionists (specifically Local Reductionists) argue that hearers must evaluate individual instances of testimony for reliability to be justified Local Reductionism evaluation. In contrast, Non-Reductionists reject the need for positive reasons to trust a speaker, favoring a 'Presumptive Right' to belief unless there is an 'undefeated defeater'—evidence that the testimony is false Non-Reductionists' Presumptive Right. Hybrid models, such as those proposed by Jennifer Lackey and Crispin Wright, seek to integrate listener evidence with the reliability of the speaker-hearer exchange Lackey's hybrid view.
Discussions on testimonial knowledge often center on the Transmission View, which questions if a hearer can acquire knowledge from a speaker who does not know the proposition themselves Transmission vs. generation. While some theorists insist on a necessity condition—that a speaker must know the proposition to transmit it—others explore cases where knowledge may be generated even through defective testimony, provided a 'guaranteeing' mechanism or agent corrects the inaccuracy Goldberg on defective testimony. Furthermore, the Assurance View emphasizes the interpersonal nature of testimony, where the act of 'telling' functions as an invitation to trust, creating a unique social bond between speaker and audience Assurance View interpersonal.
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In contemporary epistemology, testimony is broadly recognized as a mechanism for learning from others epistemologists generally agree, though the precise criteria for what constitutes a testimonial act remain a subject of significant debate.
Formal definitions often attempt to bridge the gap between speaker intent and hearer reception. C. A. J. Coady (1992) proposes a rigorous set of conditions, requiring that a statement be offered as evidence, that the speaker possess relevant credentials, and that the statement address a genuine dispute Coady proposes criteria. However, critics such as E. Fricker (1995) and Jennifer Lackey (2008) challenge Coady’s requirement that testimony must function as evidence for the hearer, noting that one can provide testimony even when the speaker is known to be unreliable Fricker and Lackey object. Peter J. Graham (1997) offers an alternative definition centered on the speaker's intentions regarding their own competence and the relevance of their statement Graham defines testimony. Others, such as Goldberg (2010b), argue that the act of asserting a proposition is not a necessary condition for testifying to it Goldberg argues assertion.
Beyond formal definitions, scholars investigate the conditions under which testimony yields knowledge. Some argue that casual, unreflective acceptance of testimony may not constitute genuine knowledge, as illustrated by Wayne Riggs (2009) in his analysis of whether a hearer is justified in asserting information received through testimony Riggs argues against. This relates to the exercise of intellectual virtues, as John Greco suggests that social-cognitive abilities are necessary to assess the sincerity and competence of a speaker Greco argues intellectual. Furthermore, the "disjunctive account" has been proposed to reconcile the speaker's intentional acts with the hearer's acquisition of knowledge, regardless of the speaker's original intent disjunctive account captures.
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Testimony is a primary source of knowledge—such as learning about historical events learning about the July 22, 2005 terrorist attack or mundane facts like the time learning the time by asking—that raises significant epistemological questions regarding how we justify beliefs acquired from others. A central debate exists between reductionist views, which require non-testimonial evidence to justify trust in a source, and anti-reductionist or direct views. Local Reductionism, for example, faces challenges in explaining how travelers can trust strangers lacking specific non-testimonial reasons, though some scholars like Kenyon (2013) argue that contextual information can support such inferences use contextual information to support.
Philosophers also explore the structural similarities between testimony, memory, and perception. Christopher Green (2006) discusses how treating memory as a message from an earlier self effectively turns memorial beliefs into testimonial ones memorially-based beliefs are transformed into, and how perceiving a testifier as a machine can similarly shift testimonial beliefs into a perceptual framework treating a testifier as a machine. The "Transmission View" suggests that testimonial knowledge requires the speaker to possess knowledge themselves speaker who does not know it, while reliability-based approaches emphasize the need for both the speaker and hearer to be reliable in their respective roles requiring both the speaker and hearer. Ultimately, the field distinguishes between lay testimony and that of epistemic authorities testimony from a layman and testimony, while acknowledging that trust can be undermined if the testifier lacks reliability or suffers from conditions that impair their judgment testifier is seriously worried about their.
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The epistemology of testimony explores how individuals acquire knowledge through the reports of others. A central debate in the field concerns whether testimony is a 'basic' or 'non-reducible' source of justification, or if it must be reduced to other forms of justification like memory, perception, or inductive reasoning [40, 48, 56].
Philosophers such as Burge, Coady, and Reid support a 'direct view' of testimony [1], while others, known as 'preservationists' (including Dummett, McDowell, and Lackey), argue that for knowledge to be transmitted, the speaker must themselves possess knowledge of the proposition [11]. This transmission process is complex; for instance, Peter Graham argues that knowledge is not directly transferred through communication, but rather information is conveyed [49].
Critics of reductionist models often point to the 'not enough evidence objection' (NEEO), which suggests that if testimony required independent inductive support, individuals would rarely be justified in believing what they are told [53]. Furthermore, 'Local Reductionism' faces criticism for the potential exclusion of young children, who lack the experience to verify their parents' reliability [20, 59]. In response, some suggest children exist in a 'credulous phase' where beliefs are justified pragmatically rather than epistemically [31].
Reliability in testimony is often analyzed through complex scenarios involving 'matching errors,' such as Graham's thought experiment where a testifier with a color-word malady provides true reports only because of corrective glasses [5, 8, 14]. In such cases, the hearer’s belief may only become knowledge after enough time (Δt) has passed for a corrective mechanism to intervene [42, 55]. Additionally, modern research explores how credibility can be influenced by social factors [19], group dynamics [43], and the 'interest-sensitive' stakes of both the speaker and the listener [58].
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Testimony is a fundamental source of knowledge that challenges traditional notions of epistemic individualism, as individuals acquire much of their understanding through others the role of testimony. Philosophically, testimony is often categorized as a belief-forming source alongside perception, memory, deduction, and induction belief categorization sources. Epistemologists debate whether testimony is fundamentally unique or if it shares structural similarities with other sources; for instance, some scholars argue for 'epistemic parity' between testimony, memory, and perception, suggesting they all preserve knowledge rather than creating it epistemic parity arguments.
Central to this field is the distinction between 'Reductionist' and 'Non-Reductionist' perspectives. Non-Reductionism is motivated by the desire to avoid the requirement that hearers possess positive, independent reasons to believe a speaker is reliable non-reductionism motivation. Conversely, some accounts suggest that trust in testimony is grounded in the hearer's belief that the testifier knows the proposition being asserted hearer trust grounding. The acquisition of knowledge through testimony is subject to environmental conditions; a hearer can only acquire knowledge if the testifier is properly connected to the truth of the proposition knowledge acquisition conditions. However, cases such as the 'Persistent Believer' scenario illustrate complexities where a testifier may lack justification for their own belief due to misleading information, yet still successfully transmit knowledge to a hearer who lacks that misleading context persistent believer case.
Furthermore, the definition of testimony is evolving to include machine-generated information, with some argueing that if machine outputs share the same epistemic status and phenomenology as human testimony, they should be categorized similarly machine testimony parity. Ultimately, the study of testimony is deeply intertwined with broader epistemic concerns, including peer disagreement, belief aggregation, and the influence of social context on interlocutor incentives social context and belief.
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Testimony is a fundamental mechanism for knowledge transmission, particularly within the context of cumulative culture passed down through generations basic source of knowledge. Philosophical inquiry into testimony explores how it provides justification for belief and how hearers acquire knowledge through the speech of others relationship between speech and testimony. A central debate exists between Reductionist and Non-Reductionist theories; opponents of Non-Reductionism argue that it permits irrational gullibility by failing to require positive reasons for trusting testimony risks of non-reductionism, while some Reductionists suggest that testimony can be treated as data where the best explanation confirms the truth of many individual cases reductionist data approach.
The reliability of testimony is often analyzed through specific case studies. For instance, Goldberg argues that hearers can acquire knowledge even when a testifier's own belief is based on wishful thinking, provided the hearer uses additional contextual clues utilizing clues for reliability. Conversely, Robert Audi suggests that receiving information from a deceptive source—such as a teacher who would lie for job retention—does not provide an adequate basis for knowledge deceptive source concerns. Furthermore, beliefs are not always derived from testimony alone; they may be sustained by a hearer's independent knowledge, a phenomenon sometimes referred to as the 'Not-Testimony' response independent knowledge sustainment. The complexity of testimonial interaction is further highlighted by instances where information is assimilated differently than the testifier intended, as seen in the example of Jimmy Olsen and Lois Lane conceptualization differences in testimony.
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Testimony is a central topic in social epistemology, concerning how individuals acquire knowledge and justification through the reports of others. Epistemologists distinguish between different approaches to justifying testimonial belief, such as the 'conservative' position, which rejects principles related to perception and testimony the 'conservative' epistemic position, and the 'moderate' position, which rejects only testimony-related principles the 'moderate' epistemic position.
Debates often center on whether testimony merely transmits knowledge or also generates justification testimony generates or transmits knowledge. For instance, Robert Audi (1997) suggests testimony generates justification but only transmits knowledge testimony generates justification and transmits knowledge, while Wright (2016a) notes views where it performs both simultaneously testimony transmits knowledge and generates justification. A significant challenge in this field is the 'Inductive Challenge to Others' (ICO), which questions how one can justify reliance on testimony without circularity the Inductive Challenge to Others. James Van Cleve argues that corroboration is not inherently dependent on others, as personal experience can verify testimonial claims corroboration of testimony is not dependent, and he suggests the strength of an inductive base relies on the success rate of past checks strength of an inductive base.
Furthermore, the nature of belief formation via testimony is often compared to perception. Weiner (2003) notes that while perception can be automatic, testimony requires an awareness that one is believing what another person presents as their own belief testimony involves awareness of presentation. However, some scholars, such as Jennifer Lackey, utilize hybrid models to distinguish between speaker and hearer testimony Jennifer Lackey defends a hybrid view, and others like Green (2006) argue that even non-conscious entities, such as machines, can support knowledge in a hearer testifier can support knowledge without phenomenology.
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```json
{
"content": "In epistemology, testimony refers to the process by which a speaker (or testifier) conveys information or beliefs to a hearer, serving as a fundamental source of knowledge and justification alongside perception, memory, and reason Reliabilism identifies sources including testimony. The concept is not strictly limited to human interaction; Green argues that even a zombie or machine can support knowledge in a hearer without conscious phenomenology.
### Definition and Scope
Philosophers generally define testimony through the relationship between a testifier (T) and a hearer (S). Peter Graham’s epistemic principle (TEST) characterizes it as a subject comprehending a presentation-as-true by a speaker Graham's TEST principle conditions. This process often involves the hearer being aware that they are accepting another person's belief, distinguishing it from automatic perceptual formation Weiner on awareness in testimonial belief. While traditionally focused on propositional content, Goldberg advocates widening the scope to include all information conveyed from speaker to hearer, not just content-preserving cases.
### Generation vs. Transmission
A central debate in the field is whether testimony merely transmits existing knowledge or generates new justification or knowledge. Robert Audi maintains that while testimony can generate justification, it can only transmit knowledge Audi on generation of justification. Conversely, other frameworks explore how testimony might transmit knowledge while simultaneously generating justification Wright on testimony transmitting knowledge. Alvin Plantinga acknowledges that testimony provides "warrant" but suggests it is cognitively inferior to seeing truths for oneself Plantinga on the limits of testimonial warrant.
### Theories of Justification
Several competing theories attempt to explain why we are justified in accepting testimony:
* Reductionism: This view suggests that our trust in testimony is justified by inductive evidence from past experiences. James Van Cleve argues that this corroboration does not inherently depend on others because one can verify instances independently (like finding beer in the fridge) Van Cleve on independent corroboration.
* Hybrid Views: Jennifer Lackey defends a hybrid view that distinguishes between 'speaker' and 'hearer
openrouter/x-ai/grok-4.1-fast 92% confidence
In epistemology, testimony is a primary mechanism for knowledge transmission, particularly in cumulative culture where it serves as a basic source of knowledge passed across generations, according to MIT Press. Key debates center on Reductionism, which demands positive reasons or evidence for trusting testimony, and Non-Reductionism, which grants presumptive reliability; opponents of Non-Reductionism, as noted in the Stanford Encyclopedia of Philosophy, contend it fosters irrational gullibility by rejecting trust requirements. Reductionists counter objections concerning children's credulity, stranger testimony, and social psychology challenges, per the same source. Illustrative cases include Jimmy Olsen unknowingly conveying knowledge about Superman to Lois Lane via assimilated information, highlighting conceptualization variances (Internet Encyclopedia of Philosophy), and shaky hearer knowledge from matching errors in testifier perception and hearer assumptions. Prominent philosophers like Elizabeth Fricker, author of 'Testimony: Knowing Through Being Told' (Internet Encyclopedia of Philosophy), Robert Audi, who denies knowledge from disbelieving teachers, and Stephen Wright, with works defending transmission including 'Knowledge Transmission' (Stanford Encyclopedia of Philosophy), shape the discourse. Further issues involve unreliable testifiers where hearers might rely on independent knowledge ('Not-Testimony' response), group justification via Jessica Brown's testimony-based account avoiding Lackey's critiques of Goldman (Stanford Encyclopedia of Philosophy), and safety in cases like Goldberg's 'Yankees-actually-won' scenario using reliability cues.
Facts (407)
Sources
Epistemology of Testimony | Internet Encyclopedia of Philosophy iep.utm.edu 203 facts
quoteJennifer Lackey (2005) states: “non–reductionists maintain that testimony is just as basic a source of justification (knowledge, warrant, entitlement, and so forth) as sense-perception, memory, inference, and the like”.
claimThe Assurance View of testimony posits that a testifier is not offering evidence to the recipient, but is instead asking the recipient to trust them, which is inconsistent with the recipient basing their belief on evidence.
quotePeter Graham states: "That a source is a source of defeaters for beliefs from another source, or even from itself, does not show that the other source depends for justification on inferential support from another source, or even itself. … The fact that my perception defeats your testimony does not show that testimony is inferential and not direct. Indeed, the fact that testimony-based beliefs sometimes defeat perceptual beliefs does not show that testimony is prior to perception."
perspectiveGreen argues that epistemic parity between testimony, memory, and perception is a more economical and likely true account of epistemic phenomena than accounts that distinguish sharply between the three sources.
accountIn the example provided by Goldberg (2005), a testifier (T) tells a hearer (S) that there is milk in the fridge based on evidence that is usually misleading because an eccentric writer (A) usually replaces the milk carton with an empty one, but A forgot to do so on this occasion.
claimGreen (2006) discusses a scenario where a testifier (T) and a hearer (S) conceptualize the object of a belief differently, such as when T tells S that object m is F, without knowing that m is the same as object n, while S knows that m is n.
quoteAlvin Plantinga states: "[I]n many situations, while testimony does indeed provide warrant, there is a cognitively superior way. I learn by way of testimony that first-order logic is complete…. I do even better, however, if I come to see these truths for myself…"
perspectiveLiberals such as Peter Graham and Alvin Plantinga argue that the possibility of interpreting testimonial utterances is insufficient to justify a belief in the reliability of testimony.
claimJennifer Lackey describes a case where a person retains perceptually-based beliefs despite having evidence that their perception is radically unreliable.
claimThe basic model of testimonially-based belief involves a testifier (T) communicating a statement (p) to an epistemic subject (S), who then believes that statement (p).
claimKnowledge-preservationists view testimony as a tool useful only for spreading knowledge rather than creating it, an analogy similar to how political libertarians view government as a tool for redistributing wealth rather than creating it.
perspectiveGreen argues that beliefs derived from the linguistic output of machines must be categorized, and classifying them as anything other than 'testimonially-based belief' multiplies epistemic categories beyond necessity.
claimJennifer Lackey defends a hybrid view of testimony that distinguishes between 'hearer testimony' and 'speaker testimony'.
quoteGoldberg (2001) argues that epistemologists of testimony should "widen our scope of interest from an exclusive focus on content-preserving cases of [testimonially-based] belief and knowledge to include all cases in which information is conveyed in a testimonially-based way from speaker to hearer."
claimJennifer Lackey defends a conservative approach to testimony against the 'infants-and-young-children' objection by examining whether similar problems afflict any approach to testimonial-based justification that includes a non-defeater condition.
referenceGreen (2006) argues that a testifier can support knowledge in a hearer even if the testifier lacks conscious phenomenology, such as in the case of a zombie or a machine.
claimThe 'reactionary' epistemic position accepts only principles regarding a priori insight, internal experiences, and deduction, while rejecting principles related to memory, enumerative induction, inference to the best explanation, perception, and testimony.
claimTomoji Shogenji argues that if an epistemic subject has a non-testimonial basis for interpreting a statement, they can infer the general reliability of testimony from that basis.
claimGoldberg posits that beliefs partly based on defective testimony can amount to knowledge if the other part of the belief's basis, such as A's guaranteeing function, cures the defect in the testimony.
perspectivePeter Graham (2004) argues that the presence of human freedom in testimonial cases is not a significant reason to prefer a conservative approach to testimony.
referenceGraham's epistemic principle (TEST) includes broad conditions for testimony: 'If a subject S (seemingly) comprehends a (seeming) presentation-as-true by a (seeming) speaker that [p] ….'
claimA second liberal route to resist Jennifer Lackey's argument is to claim that young children are in principle capable of appreciating reasons or defeaters, but possess a poor inductive base regarding confirmed reports.
perspectiveGreen (2006) argues that it is unclear whether testimony is fundamentally different from perception regarding the necessity of higher-order beliefs about the source.
claimThe Reidian approach to testimony holds that testimonially-based beliefs are properly non-inferential, or direct.
claimJames Van Cleve argues that corroboration of testimony is not inherently dependent on others because he has verified many instances of testimony throughout his life, such as the existence of the Grand Canyon and the Taj Mahal, as well as quotidian occurrences like finding beer in the fridge.
claimPeter Graham (2006) categorizes philosophers who support a non-direct view of testimony as including Adler (2002), Audi (1997, 2002, 2004, 2006), Hume (1739), Kusch (2002), Lackey (2003, 2006), Lehrer (1994), Lyons (1997), Faulkner (2000), Fricker (1987, 1994, 1995, 2002, 2006a), and Root (1998, 2001).
claimSome epistemologists view testimony as a mechanism for spreading knowledge rather than creating it, contrasting it with perception, which is viewed as a source of knowledge for the epistemic community as a whole.
claimJennifer Lackey (2006) endorses the argument that testimony requires higher epistemic demands than perception because people can lie, whereas the physical environment cannot.
claimA person can receive testimony from a computer-generated voice, such as a credit card company's automated fraud alert, which serves as an example of machine testimony.
claimThe non-inferentialist view of testimony sees testimony as an input to a machine where a testifier (T) tells a person (S) that a proposition (p) is true, and S's testimony-processing faculty causes S to believe that p.
claimIf a testifier is seriously worried about their own reliability, such as fearing they are a brain in a vat, a hearer cannot reasonably gain knowledge by relying on that testifier's testimony.
perspectiveCritics of Tyler Burge's argument regarding testimony contend that he fails to account for the necessary assumption that the testifier's rational faculties are functioning properly.
quoteBeliefs based on testimony are part of the web of beliefs we regularly rely on when we form a variety of expectations. This means that the hypothesis that testimony is credible plays a crucial role when we form these expectations. As a result, even if we do not deliberately seek confirmation of the credibility hypothesis, it receives tacit confirmation whenever observation matches the expectations that are in part based on the credibility hypothesis. Even if the degree of tacit confirmation by a single observation is small, there are plenty of such observations. Their cumulative effect is substantial and should be sufficient for justifying our trust in testimony.
perspectiveDavid Hume's reductionist perspective posits that individuals properly form beliefs based on testimony only because they have observed other confirmed instances of the veracity of human testimony, meaning testimonial justification is reducible to perceptual, memorial, and inferential justification.
claimThe epistemology of testimony article in the Internet Encyclopedia of Philosophy defines testimony for its purposes using the rough formulation: 'T told S that p'.
claimEpistemologists generally agree that for a subject to gain knowledge via testimony from a testifier, the subject must satisfy internal conditions for knowledge, the proposition must be true, and the testifier must be properly connected to the fact, which includes satisfying an environmental condition as established by Gettier (1963).
perspectiveKnowledge-preservationists argue that if evidence makes a testifier's belief improper, it also makes their testimony improper and the hearer's reliance on that testimony improper.
claimWeiner (2003b) argues that viewing testimony as an assurance does not contradict the requirement that a recipient must have evidence for their testimonially-based beliefs.
claimLackey (1999) identifies cases where a speaker reliably passes information to a hearer even when the speaker does not know the proposition due to personal or warranted doubts, demonstrating that the speaker's defeaters are not necessarily transmitted to the hearer.
claimTreating a testifier as a machine, such as a telescope, transforms testimonially-based beliefs into perceptually-based beliefs by treating human beings as an environmental medium through which information passes.
claimIn Graham's (2000a) example, if a hearer learned that a testifier perceives the sky as red due to their malady, the hearer would likely lose trust in the testifier's reports about colors.
claimGreen (2006) suggests that a testifier acts as an epistemic agent or employee for the recipient, where the testifier takes responsibility for specific areas of epistemic business, while the recipient retains the responsibility to select the testifier properly.
claimPeter Graham (2000c) argues that it is possible for testifiers to be generally unreliable even if they successfully interpret each other's statements, challenging the view that interpretation requires an assumption of reliability.
claimThe 'Not-Testimony' response posits that a hearer's belief is not based solely on a testifier's testimony, but also on additional signs or knowledge that indicate the testifier's reliability or unreliability.
claimChristopher Green argues that if memory is treated as the interpretation of a message from an earlier time slice of oneself, then memorially-based beliefs are transformed into testimonially-based beliefs, and this transformation should not create or preserve epistemic status or affect the structure of its explanation.
perspectiveJennifer Lackey disputes the account of knowledge as the norm of assertion, as proposed by Timothy Williamson, by arguing that it is proper for a testifier to assert a proposition even if they do not know or believe it, provided the testimony is reliable.
claimThe epistemology of testimony involves analyzing the external conditions required for a recipient (S) to gain knowledge from a testifier (T), specifically questioning whether the testifier must know the proposition (p) herself, whether the testimony must be true, and whether the testifier must reliably testify.
referenceChristopher J. Insole published 'Seeing Off the Local Threat to Irreducible Knowledge by Testimony' in Philosophical Quarterly 50:44-56 in 2000.
perspectiveLackey (2006a) argues that a subject requires positive reasons to believe a testifier's testimony, despite her criticism of reductionism.
referencePeter J. Graham published 'What is Testimony?' in The Philosophical Quarterly in 1997.
claimCritics of Tyler Burge's argument for a priori entitlement to testimony suggest that he overlooks the necessary assumption that the testifier's rational faculties are functioning properly.
claimChristopher Green argues that testimony and memory are on an epistemic par.
quoteWeiner (2003) states: "When we form beliefs through perception, we may do so automatically, without any particular belief about how our perceptual system works. When we form beliefs through testimony, at some level we are aware that we are believing what a person says, and that this person is presenting her testimony as her own belief."
claimCoady (1992) argues that interpreting the utterances of others requires a presupposition that testifiers are generally reliable, a view built on Donald Davidson’s theories of radical interpretation.
claimGoldberg argues that S's belief is safe because the presence of A (an authority or corrector) would prevent T's false testimony from being believed, even if T's testimony itself is unsafe due to being based on usually misleading evidence.
claimShogenji argues that the hypothesis that testimony is credible receives tacit confirmation whenever observations match expectations that are based on that credibility hypothesis, providing a cumulative effect that justifies trust in testimony.
referencePeter Graham provides lists of adversaries in the literature regarding inferential versus direct views of testimony in his 2006 work.
quoteRobert Audi (2006) states: "[T] must in some sense, though not necessarily by conscious choice, select what to attend to, and in doing so can also lie or, in a certain way, mislead … For the basic sources, there is no comparable analogue of such voluntary representation of information."
quoteRobert Audi argues against the possibility of gaining knowledge from the biology teacher in Jennifer Lackey's example, stating: “If … [the students] simply take [the teacher’s] word, they are taking the word of someone who will deceive them when job retention requires it…. It is highly doubtful that this kind of testimonial origin would be an adequate basis of knowledge.”
perspectivePaul Faulkner argues that because testimony originates from a person rather than an inanimate object, one should be more demanding regarding testimonially-based beliefs than perceptually-based beliefs.
claimGreen suggests that transforming perceptually-based beliefs into testimonially-based beliefs involves anthropomorphizing sense faculties by imagining a world where sense faculties are operated by individuals who present messages about the environment, resulting in the same structure of explanation for epistemic status.
claimIn the case of a testifier with pathological lies and misperceptions, it is not obvious that a recipient can gain knowledge from their statements, as the testifier appears insane, and a recipient would need to know the testifier is a reliable speaker despite their condition to gain knowledge.
claimTurning memorially-based beliefs into testimonially-based beliefs requires treating the believer at one time as a different person from the believer at a later time.
claimPeter Graham (2006) categorizes philosophers who support a direct view of testimony as including Burge (1993, 1997, 1999), Coady (1973, 1992), Dummett (1994), Goldberg (2006), McDowell (1994), Quinton (1973), Reid (1764), Ross (1986), Rysiew (2000), Stevenson (1993), Strawson (1994), and Weiner (2003a).
claimGoldberg (2006) argues that both reductionists and non-reductionists can subscribe to a 'buck-passing principle,' where a recipient of testimony retains an epistemic duty to select a reliable testifier, similar to a client's duty to select a competent lawyer.
claimGoldberg suggests that in cases where S knows about A's role, S is not relying solely on T, but on a hybrid of T and A.
quoteHinchman (2007) states: “[H]ow could [T] presume to provide this warrant [for S’s belief that p]? One way you could provide it is by presenting yourself to A as a reliable gauge of the truth. … The proposal … simply leaves out the act of assurance. Assuring [S] that p isn’t merely asserting that p with the thought that you thereby give [S] evidence for p, since you’re such a reliable asserter (or believer). That formula omits the most basic respect in which you address people, converse with people—inviting them to believe you, not merely what you say.”
claimRobert Audi (2006) asserts that testimony is operationally dependent on perception, noting that to receive testimony about the time, one must hear or otherwise perceive the speaker.
accountIn Graham's (2000a) example, scientists install spectrum-reversing glasses on a testifier who has a color-word malady so that the testifier's reports become factually correct.
claimWhile some philosophers require positive reasons to believe in the reliability of a testifier, most do not insist that a subject must have a sufficiently large inductive base to justify an inference from other beliefs or reduce testimony to perception, memory, or inference.
claimGoldberg (2006) argues that even if a testifier assumes responsibility for a proposition, the recipient of the testimony retains an epistemic duty to select a reliable testifier, similar to a client's duty to select a competent lawyer.
claimThe Internet Encyclopedia of Philosophy article on the Epistemology of Testimony adopts the working definition of testimony as "T told S that p" to navigate disputes regarding the exact nature of testimony.
referencePeter Graham presents a thought experiment involving a testifier (T) raised in an environment where color words are swapped (e.g., "blue" means red), whose testimony is corrected by spectrum-reversing glasses, resulting in true reports despite the underlying errors.
claimA testimonially-based belief is formed when an epistemic subject (S) accepts a proposition (p) told to them by a testifier (T).
claimThe 'moderate' epistemic position rejects only the principle regarding testimony.
claimElizabeth Fricker argues that when a hearer forms a belief based on a teller's testimony, the hearer typically holds a higher-order belief that the teller would not assert or vouch for the proposition unless the teller knew it to be true.
claimIn his 2000 work, Shogenji argues that the reliability of perception can be confirmed through the use of perception without circularity, using reasoning similar to his argument for the reliability of testimony.
claimJennifer Lackey (2006) identifies Welbourne (1979, 1981, 1994), Hardwig (1985, 1991), Ross (1986), Burge (1993, 1997), Plantinga (1993), McDowell (1994), Williamson (1996), Audi (1997), Owens (2000), and Dummett (1994) as preservationists, defined as those who hold that for a speaker to transmit knowledge, the speaker must know the proposition in question.
procedureChristopher Green proposes transforming testimonially-based beliefs into memorially-based beliefs by applying the legal fiction of agency, 'qui facit per alium, facit per se' ('he who acts through another, acts himself'), treating the testifier as the believer's epistemic agent.
perspectiveThe Internet Encyclopedia of Philosophy article on the Epistemology of Testimony classifies approaches to testimonially-based justification as "Liberal" or "Conservative," where Liberals are less demanding and Conservatives are more demanding regarding what counts as justified belief or knowledge.
claimRecipients of testimony do not necessarily form higher-order beliefs about the reliability of that testimony, just as perceivers do not necessarily form higher-order beliefs about their perceptual faculties.
claimThe inferentialist view of testimony sees testimonially-based belief as the acceptance of an argument where a person (S) concludes that a proposition (p) is true because a testifier (T) is telling them (p), and T or people like T have generally been reliable in the past.
claimThe 'Not-Testimony' response argues that beliefs based on machine output are not 'testimonially-based belief' because machines cannot perform speech acts, and testimony is defined as a speech act.
claimIn Graham's (2000a) example, the hearer's knowledge is considered shaky because it relies on two large, matching errors in assumptions—the testifier's malady and the corrective glasses—that happen to result in true reports.
claimPeter Graham argues that a speaker testifies if their statement that p is offered as evidence that p.
claimKnowledge-preservationists counter Goldberg's (2001) false testimony example by arguing that either the speaker knew and testified to the true proposition, or the speaker did not testify to the true proposition, meaning the listener inferred the knowledge independently of the testimony.
referenceGreen (2006) defends responses to Jennifer Lackey's examples by arguing that a hearer takes the testifier as an agent, and therefore the hearer is responsible for the testifier's misbehavior if they trust a misbehaving testifier.
procedureInferentialists model testimonially-based belief as a four-step argument: (1) T is telling me that p; (2) T, or people like T, have generally been reliable in the past; (3) T is probably reliable on this occasion; (4) p.
perspectiveSome epistemologists argue that testimony is a type of speech act that requires the testifier to be conscious, and therefore machine testimony does not qualify as 'testimonially-based belief'.
procedureDefenders of knowledge-preservationism can respond to counterexamples using three methods: (1) the 'Ignorant-S' response, which denies that the subject really knows the proposition; (2) the 'Knowing-T' response, which claims that the speaker really does know the proposition; or (3) the 'Not-Testimony' response, which denies that the subject's belief is actually based on the speaker's testimony.
referenceElizabeth Fricker published 'Testimony and Epistemic Autonomy' in the 2006 collection edited by Lackey and Sosa.
claimPaul Faulkner (2000) argues that testimony requires more stringent epistemic demands than perception because testimony originates from a person capable of deception, whereas inanimate objects in the perceptual environment do not.
quoteDavid Hume stated: "[T]here is no species of reasoning more common, more useful, and more necessary to human life, than that which is derived from the testimony of men, and the reports of eye-witnesses and spectators. … [O]ur assurance in any argument of this kind is derived from no other principle than our observation of the veracity of human testimony, and of the usual conformity of facts to the reports of witnesses."
claimPeter Graham defines a "reactionary" as someone who accepts only principles of a priori insight, internal experiences, and deduction, while rejecting principles related to memory, enumerative induction, inference to the best explanation, perception, and testimony.
claimThe nature of perception does not necessarily inhibit higher-order beliefs, and the nature of testimony does not necessarily produce higher-order beliefs.
claimThe Internet Encyclopedia of Philosophy article on the Epistemology of Testimony focuses on the general epistemology of testimony rather than the specific epistemology of human testimony.
claimJennifer Lackey provides examples where a testifier is gripped by skeptical worries or believes their perceptual abilities are faulty.
claimMoran (2005), Ross (1986), and Hinchman (2005, 2007) argue that because a testifier assumes responsibility for the truth of a proposition, the epistemic responsibilities of the recipient are necessarily lessened.
claimJames Van Cleve concludes that the strength of an inductive base for testimony depends not on the proportion of testimonial beliefs checked, but on the proportion of checks taken that have had positive results.
claimThe 'conservative' epistemic position rejects only principles regarding perception and testimony.
quoteChildren go through a credulous phase during which they believe without reason nearly everything they are told; these beliefs are justified only in a pragmatic sense, not in an epistemic sense.
claimMichael Dummett (1994) suggests that knowledge-preservationism aligns best with a less demanding approach to epistemology by drawing a strong analogy between testimony and memory.
claimThe 'Not-Testimony' response to Jennifer Lackey's biology teacher example suggests that the teacher is not actually testifying, but rather acting as a conduit for the school board, which is the true testifier.
quotePeter Graham (2004) states: “The central claim the Anti-Reductionist makes is that the epistemologies of perception, memory, and testimony should all look more or less alike.”
claimRichard Foley argues that trust in others, which is central to testimony, is no less justified than trust in oneself, which is central to memory.
accountIn an example of conceptualization differences, Jimmy Olsen (the testifier) tells Lois Lane (the hearer) that Clark Kent's favorite ice cream flavor is chocolate, without knowing that Clark Kent is Superman. Lois Lane, who knows that Clark Kent is Superman, assimilates this information into a single 'Clark/Superman' file, thereby gaining knowledge about Superman's favorite ice cream flavor that Jimmy Olsen did not intend to convey.
claimTyler Burge (1993) argues that a subject is a priori entitled to accept a statement as true if that statement is intelligible and presented as true.
referenceElizabeth Fricker authored 'Testimony: Knowing Through Being Told', published in the 'Handbook of Epistemology' edited by I. Niiniluoto, Matti Sintonen, and J. Wolenski in 2004.
claimAt time t, the testifier's (T) belief and testimony are unreliable, but at time t+Δt, the testifier also knows that p because the testifier can rely on the failure of the agent or mechanism (A) to correct the testimony.
quoteTyler Burge states in his 1993 work: "We are a priori entitled to accept something that is prima facie intelligible and presented as true. For prima facie intelligible propositional contents prima facie presented as true bear an a priori prima facie conceptual relation to a rational source of true presentations-as-true: Intelligible propositional expressions presuppose rational abilities and entitlement; so intelligible presentations-as-true come prima facie backed by a rational source or resource of reason; and both the content of intelligible propositional presentations-as-true and the prima facie rationality of their source indicate a prima facie source of truth. Intelligible affirmation is the face of reason; reason is a guide to truth. We are a priori prima facie entitled to take intelligible affirmation at face value."
claimThe 'Not-Testimony' response suggests that in cases where a testifier is unreliable, a hearer's belief may be sustained by the hearer's independent knowledge rather than the testimony alone.
claimThomas Reid (1785) defines testimony as a situation where the epistemic subject relies on the testifier's authority for the truth of a proposition.
perspectiveConservatives in epistemology argue that transforming testimony into perception is not epistemically innocent because anthropomorphizing sense faculties introduces human agency, while treating a testifier as a perceptual device removes it.
claimIf T tells S that p at time t, and it would take A at least time Δt to correct T's testimony if it were false, S's belief at time t is not safe, but S's belief at time t+Δt may constitute knowledge.
perspectiveReductionism views testimony as akin to inference and places a relatively heavy burden on the recipient of testimony, whereas anti-reductionism views testimony as akin to perception or memory and places a relatively light burden on the recipient.
claimGoldberg argues that at time t+Δt, T also knows that p because T has the right to rely on A's failure to correct the testimony that p, making T's testimony safe and reliable at that later time.
referenceMitchell Green argues that a hearer (S) who trusts a misbehaving testifier (T) should be held responsible for the testifier's misbehavior because the hearer treats the testifier as an agent.
claimA liberal response to Jennifer Lackey's argument posits that young children are justified in their beliefs because they lack the epistemic obligations associated with normative defeaters, as they do not possess the capacity to appreciate reasons or resolve conflicting claims.
quoteGraham (2000) posits that "knowledge is not transferred through communication, rather Information is conveyed."
claimA hearer's (S) knowledge derived from a testifier (T) is considered shaky when the testimony is true only because of matching errors in the hearer's assumptions and the testifier's perception.
perspectiveEpistemologists debate whether a recipient of testimony must possess beliefs or inductive support regarding the reliability of the testifier to be justified in their belief, or if the testifier's actual reliability is sufficient.
perspectiveRobert Audi argues that students cannot gain knowledge from a teacher who does not believe the lesson they are teaching, stating that if students simply take the word of a teacher who would deceive them when job retention requires it, it is highly doubtful that this testimonial origin provides an adequate basis for knowledge.
claimTomoji Shogenji argues that the ubiquity of testimonially-based beliefs and the reliance on the reliability of testimony can be used to provide greater confirmation for the reliability of testimony.
claimRobert Audi (2002) argues that apart from perceptual justification for believing that a testifier attested to a proposition, one cannot acquire justification for believing that proposition on the basis of that testimony.
claimIf the testifier (T) tells the hearer (S) that p at time t, and the agent or mechanism (A) requires time Δt to correct false testimony, the hearer's belief is not safe at time t, but may become knowledge at time t+Δt after the agent or mechanism has had the opportunity to correct the testimony.
claimKnowledge-preservationism is the thesis that a subject's testimonially-based knowledge that a proposition is true requires the speaker to also know that proposition.
claimThe Hawthorne-Stanley interest-sensitive view of knowledge posits that a speaker can properly assert a proposition to a listener if the speaker has enough certainty for the listener's specific stakes, even if the speaker's own stakes would require a higher level of certainty to possess knowledge of that proposition.
quoteAlvin Plantinga, citing Thomas Reid, stated in 1993: "Reid is surely right in thinking that the beliefs we form by way of credulity or testimony are typically held in the basic way, not by way of inductive or abductive evidence from other things I believe. I am five years old; my father tells me that Australia is a large country and occupies an entire continent all by itself. I don’t say to myself, “My father says thus and so; most of the time when I have checked what he says has turned out to be true; so probably this is; so probably Australia is a very large country that occupies an entire continent by itself.” I could reason that way and in certain specialized circumstances we do reason that way. But typically we don’t. Typically we just believe what we are told, and believe it in the basic way. … I say I could reason in the inductive way to what testimony testifies to; but of course I could not have reasoned thus in coming to the first beliefs I held on the basis of testimony."
claimJennifer Lackey presents a second thought experiment involving a person who suffers from matching misperceptions and pathological lies, where the person consistently misidentifies zebras as elephants but has a pathological urge to tell people that what she sees are zebras.
claimShogenji argues that the reliability of perception can be confirmed by the use of perception without circularity, using reasoning similar to his argument for the reliability of testimony.
claimJennifer Lackey presents examples where a testifier (T) suffers from skeptical worries or believes their perceptual abilities are faulty, which challenges whether a hearer (S) can acquire knowledge from that testifier's testimony.
claimThomas Reid (1785) distinguishes testimony by the epistemic subject relying on the testifier's authority for the truth of a proposition.
claimJames Van Cleve summarizes the argument that the vast majority or totality of what passes for corroboration of testimony relies on other testimony.
claimFew contemporary philosophers endorse the full form of David Hume's reductionist or inferentialist approach to testimonially-based belief.
claimJennifer Lackey argues that a general inductive basis for belief in testimony fails because the category of testimonially-based beliefs is too heterogeneous to support a single, relevant induction.
accountIn a case discussed by Graham (2000b), a testifier (T) cannot distinguish between two twins (A and B), but the hearer (S) knows that twin B could not have knocked over a vase; therefore, when the testifier claims twin A knocked over the vase, the hearer's belief is sustained by the hearer's independent knowledge that twin B did not do it.
claimMichael Dummett suggests that both memory and testimony are merely means of preserving or transmitting knowledge rather than creating it, and that both are direct and do not require supporting beliefs.
claimAlvin Plantinga criticizes the view that testimony is necessarily evidence, arguing instead that testimony only supplies evidence when the contingent human design plan provides for it, specifically in an environment where testifiers generally speak the truth.
claimA second liberal response to Jennifer Lackey's argument is that children possess the capacity to appreciate reasons but lack a sufficient inductive base of confirmed reports to justify their testimonially-based beliefs.
claimAn alternative to the knowledge-based testimonial environmental condition is the requirement that the speaker possesses the information that the proposition is true.
claimGreen argues that the epistemic parity of testimony, memory, and perception follows from the epistemic innocence of transformations that turn instances of testimonially-based beliefs into instances of beliefs based on the other two sources, preserving the structure of the explanation of epistemic status.
claimSanford Goldberg argues that the hearer's (S) belief is safe because the presence of an agent or mechanism (A) would prevent the testifier's (T) false testimony from being believed, even though the testifier's testimony is unsafe because it is based on usually misleading evidence.
referenceGraham (2004) examines the argument that because free actions are indeterministic, the environment for testimonially-based beliefs cannot be as regular and law-governed as the environment for perceptually-based beliefs.
claimCritics argue that Tyler Burge's argument regarding the reliability of testifiers is problematic because it implies that individuals in any possible world are entitled to believe they are in a world where testifiers are generally reliable.
claimPeter Graham (2006) argues that the fact that one source of knowledge can defeat another does not imply that the defeated source depends on inferential support from the other, nor does it show that testimony is inferior to perception.
claimPeter Graham defines a "conservative" as someone who rejects only principles regarding perception and testimony, a "moderate" as someone who rejects only the principle regarding testimony, and a "liberal" as someone who accepts the principle for testimony.
claimThomas Reid, a prototype non-reductionist, acknowledged significant disanalogies between beliefs based on perception and beliefs based on testimony.
accountAlvin Plantinga illustrates the 'basic way' of forming beliefs via testimony with the example of a five-year-old child accepting their father's statement about Australia's size without performing an inductive check on the father's reliability.
perspectiveThe 'knowledge-preservationist' perspective argues that when a hearer (S) forms a belief based on a testifier (T) who conceptualizes the object differently, S's belief is either inferentially-based or T did in fact communicate the relevant information to S.
claimSanford Goldberg suggests that beliefs partly based on defective testimony can constitute knowledge if the other part of the belief's basis, specifically the guaranteeing function of the agent or mechanism (A), cures the defect in the testimony.
claimIn the context of epistemology, testimony is not limited to formal courtroom testimony but encompasses any instance where one person communicates information to another person.
quoteRobert Audi states: "[W]e cannot test the reliability of one of these basic sources [that is, for Audi, a source like perception or memory, but not testimony] or even confirm an instance of it without relying on that very source. … With testimony, one can, in principle, check reliability using any of the standard basic sources."
claimSanford Goldberg asserts that in cases where the hearer (S) knows about the role of the agent or mechanism (A), the hearer relies on a 'T-in-A's-presence' hybrid rather than relying solely on the testifier (T).
claimMitchell Green argues that machine testimony should be considered genuine testimony because if two beliefs have the same epistemic status, content, cognitive ability, and phenomenology, they should be categorized similarly by epistemologists.
quoteThomas Reid (1785) stated: “There is no doubt an analogy between the evidence of the senses and the evidence of testimony. … But there is a real difference between the two as well as a similarity. When we believe something on the basis of someone’s testimony, we rely on that person’s authority. But we have no such authority for believing our senses.”
claimC.A.J. Coady (1992) argues that a speaker testifies only if they possess the relevant competence and their statement that p is directed to those in need of evidence for whom p is relevant to a disputed or unresolved question.
accountGoldberg (2001) describes a scenario where a speaker testifies falsely (claiming to see Jones at a party), but the listener gains knowledge by inferring that the speaker misidentified the person, thereby concluding that the speaker saw someone wearing a pink shirt.
claimJennifer Lackey defends a conservative approach to testimony against the objection that it places improper epistemic demands on young children who lack the capacity to evaluate the reliability of testifiers.
claimTestimonial liberals generally maintain that an individual's entitlement to believe testimony is defeasible if contrary information about the proposition or the testimony itself is available.
claimNon-inferentialists view testimony as a direct input to a cognitive faculty, where the act of communication triggers the belief without an intervening argument.
claimSeveral philosophers have endorsed the principle that a recipient of testimony can only come to know what is testified to if the testifier knows the subject matter of their assertion.
quoteGalen Strawson (1994) suggests that testimony as a source of belief requires other sources like perception, stating: "[T]he employment of perception and memory is a necessary condition of the acquisition and retention of any knowledge (or belief) which is communicated linguistically…"
quoteReid is surely right in thinking that the beliefs we form by way of credulity or testimony are typically held in the basic way, not by way of inductive or abductive evidence from other things I believe.
claimBeliefs can be categorized based on their source or root, such as perceptual, deductive, inductive, memorial, or testimonial.
claimJennifer Lackey argues that if young children or animals cannot satisfy a 'positive-reasons demand' for testimony-based beliefs because they cannot appreciate reasons, they are also unable to satisfy a 'no-defeater condition' regarding normative or doxastic defeaters.
claimC.A.J. Coady argues that the act of interpreting testimonial utterances requires an assumption that testimony is reliable.
perspectiveEpistemologists debate whether a testifier must possess knowledge of a statement for the recipient of that testimony to also possess knowledge of it.
claimTestimonial knowledge-preservationists, as listed by Jennifer Lackey in 2003, argue that for a subject S to know a proposition p via testimony, the testifier T must themselves know that p, or satisfy a similar non-testimonial condition.
referenceJennifer Lackey (2006a) and Peter Graham (2006) provide literature reviews categorizing adversaries in the testimony debate based on reductionism versus nonreductionism and inferential versus direct views.
claimGoldberg argues that in the 'Yankees-actually-won' case, the hearer's belief is safe and counts as knowledge because the hearer utilizes clues about the testifier's reliability—such as eye contact—in addition to the testimony itself, even when the testifier's own belief is based on wishful thinking.
claimLiberals such as Graham and Plantinga argue that the possibility of interpreting testimonial utterances does not necessarily justify belief in the reliability of testimony, challenging Coady’s Davidsonian argument.
claimAlvin Plantinga (1993) and Robert Audi (2006) suggest that testimony differs from sources like perception because testimonially-based beliefs can be defeated or trumped by other sources of evidence in ways that perception cannot.
perspectiveGreen argues that it is not clear that testimony is fundamentally different from perception regarding the necessity of holding higher-order beliefs about the source of the information.
claimMiranda Fricker suggests that a hearer (S) possesses an unusual amount of freedom regarding the formation of beliefs based on testimony.
quoteFricker (2006b) states: "Once a hearer forms belief that [p] on a teller T’s say-so, she is consequently committed to the proposition that T knows that [p]. But her belief about T which constitutes this trust, antecedent to her utterance, is something like this: T is such that not easily would she assert that [p], vouch for the truth of [p], unless she knew that [p]."
referenceGraham (2000a) presents a case where a testifier was raised in an environment where color words are systematically swapped, such that "blue" refers to the color red, "red" to blue, "green" to yellow, and "yellow" to green.
claimTyler Burge argues that we may ignore possible worlds where testifiers' truth-seeking faculties are not functioning properly because they are not relevant alternatives, similar to how non-skeptics ignore brain-in-a-vat scenarios.
claimGreen (2006) excludes beliefs that cannot be perceptually-based, such as mathematical facts, from his argument regarding the epistemic parity of testimony, memory, and perception.
referenceElizabeth Fricker published 'Varieties of Anti-Reductionism About Testimony—A Reply to Goldberg and Henderson' in Philosophy and Phenomenological Research in 2006.
claimThe hypothesis that testimony is reliable receives tacit confirmation whenever observations match expectations that are based on the credibility of testimony, creating a cumulative effect that justifies trust in testimony.
quoteMichael Dummett (1994) stated: "In the case of testimony … if the concept of knowledge is to be of any use at all, and if we are to be held to know anything resembling the body of truths we normally take ourselves to know, the non-inferential character of our acceptance of what others tell us must be acknowledged as an epistemological principle, rather than a mere psychological phenomenon. Testimony should not be regarded as a source, and still less as a ground, for knowledge: it is the transmission from one individual to another of knowledge acquired by whatever means."
claimTyler Burge (1993) argues that a subject (S) is a priori entitled to accept a testifier's (T) statement if that statement is intelligible and presented as true.
claimPeter Graham posits a scenario involving a group of people who are honest and skilled at interpreting each other's utterances but remain unreliable testifiers because perceptual or memory failures lead them to hold mostly false beliefs about the world.
claimMoran (2006), Watson (2004), Hinchman (2007), Ross (1986), Fried (1978), and Austin (1946) promote the view that in testifying, the testifier offers an assurance to the epistemic subject that a proposition is true, which is akin to a promise.
quoteAlvin Plantinga (1993) characterizes testimony as a "second-class citizen of the epistemic republic" if it requires the speaker to know the proposition being communicated.
claimThe Humean approach to testimony holds that individuals infer the reliability of a present instance of testimony from the reliability of earlier instances.
claimPeter Graham (2000c) provides a counter-example to the necessity of reliability in interpretation by imagining a group of people who are honest and skilled at interpreting each other, but who hold mostly false beliefs about the world due to perceptual or memory failures.
claimGraham (2004) argues that if a libertarian approach to human freedom undermines the predictability of human actions, it would also undermine a conservative approach to testimony, as a subject could never have a basis to believe a testifier is likely to be honest.
claimThomas Reid's theory of testimony holds that testimonially-based justification is not reducible to perceptual or inferential justification because it relies on an innate faculty.
claimBeliefs can be based on multiple sources simultaneously, such as being partly testimonially-based and partly perceptually-based, or partly inductively-based and partly memorially-based.
claimThe 'liberal' epistemic position accepts the principle regarding testimony.
perspectiveGreen argues that machine testimony should be classified as testimony if two beliefs share the same epistemic status, contents, cognitive ability, and phenomenology for the subject, as treating them differently would be unnecessarily duplicative.
quoteFricker (2006b) states: "When the hearer [S] … believes [T] because she takes his speech at face value, as an expression of knowledge, then … [S]’s belief in what she is told is grounded in her belief that T knows what he asserted."
claimFor a subject S to acquire knowledge through a testifier T's testimony, the proposition p must be true, and the testifier T must be properly connected to the fact that p, satisfying an environmental condition.
claimIf a testifier's actions are treated as the believer's own actions, the transfer of information from testifier to believer is structurally equivalent to the transfer of information from a person at one time to themselves at a later time via memory.
claimPeter Graham (1997) defines testimony broadly, arguing that a speaker testifies if their statement that p is offered as evidence that p.
perspectiveThe Internet Encyclopedia of Philosophy notes that various characterizations of testimony—such as assurance, epistemic agency, transfer of reasons, and passing the epistemic buck—are not necessarily mutually exclusive and could all be true simultaneously.
accountGoldberg (2005) presents a case where unreliable testimony produces testimonially-based knowledge: a testifier (T) sees evidence that is usually misleading (an empty milk carton) but happens to be accurate on this occasion because an eccentric writer (A) forgot to replace the full carton with an empty one. T tells the hearer (S) that there is milk in the fridge, and A, who is nearby, would have corrected T had the testimony been incorrect.
claimJennifer Lackey presents a thought experiment involving a biology teacher who does not believe in evolution but teaches it reliably because the school board requires her to do so, arguing that students can still gain knowledge from this testimony.
claimThomas Reid suggests that humans possess an innate faculty that causes them to trust those who testify, which is not confirmed by personally observed earlier instances.
claimCoady documents that David Hume, when describing the inductive base for a belief in the reliability of testimony, mistakenly relies on evidence drawn from other people's testimony.
claimTestimony is defined as any instance where one person tells something to another person, rather than being limited to formal courtroom testimony.
claimConservative epistemologists argue that there is an inherent difference between relying on one's own earlier efforts and relying on someone else's testimony, such that replacing the subject 'S at time 1' with 'T' (a testifier) inherently changes the structure of the explanation of a belief's epistemic status.
Epistemological Problems of Testimony plato.stanford.edu Apr 1, 2021 97 facts
claimThere is significant academic literature regarding the relationship between testimony and assertion, as well as the role of eyewitness testimony in legal contexts, such as the work of Wells & Olson (2003) and Burroughs & Tollefsen (2016).
referenceDavid Christensen and Hilary Kornblith published the paper 'Testimony, Memory, and the Limits of the A Priori' in the journal Philosophical Studies in 1997.
claimA primary motivation for the Transmission View is the analogy between memory and testimony, which suggests that just as one cannot acquire memorial knowledge of a proposition today without having known it previously, one cannot acquire testimonial knowledge of a proposition from a speaker who does not know it themselves.
claimTestimonial Reliabilists who endorse an Anti-Individualistic approach explain differences in testimonial justification between scenarios by requiring both the speaker and hearer to be reliable producers and consumers of testimony.
referenceC. A. J. Coady published the paper 'Testimony, Observation and Autonomous Knowledge' in 1994.
referenceWright (2016a) provides a discussion of epistemological views where testimony transmits knowledge while simultaneously generating justification.
claimLocal Reductionism avoids the problems of Global Reductionism by evaluating the reliability of individual pieces of testimony on a case-by-case basis rather than treating testimony as a unified category.
referenceAxel Gelfert revisited David Hume's views on testimony in a 2010 article.
claimEpistemologists distinguish between testimony from a layman and testimony from an epistemic authority, asserting that beliefs based on the testimony of an epistemic authority are epistemically superior to those based on the testimony of a layman.
claimAngus Ross investigates the reasons why individuals believe what they are told in his 1986 paper 'Why Do We Believe What We Are Told?' published in Ratio.
accountIn the scenario where a reliable friend testifies that a favorite team won a game, a hearer is justified in believing the testimony because the friend is known to be a reliable reporter and there is no reason to doubt the statement.
claimA hearer (H) receives testimony that a proposition (p) by a speaker (S) making an act of communication (a) if and only if the hearer reasonably takes (a) as conveying the information that (p) in virtue of the communicable content of (a).
claimOpponents of Local Reductionism argue that individuals can be justified in believing a speaker's testimony even without non-testimonial reasons to support the inference from the speaker's statement to the truth of the statement.
claimThe author of the Stanford Encyclopedia of Philosophy entry 'Epistemological Problems of Testimony' received feedback on the project from Jennifer Lackey and Sandy Goldberg.
claimRichard Moran's 2005 article 'Getting Told and Being Believed' analyzes the dynamics of being told information and the act of believing that testimony.
claimA primary motivation for Reductionism is the concern regarding gullibility; Reductionists argue that without the requirement for positive reasons to trust a speaker, individuals would be justified in accepting testimony in irresponsible cases, such as believing a random blogger without evidence of reliability.
claimLocal Reductionism fails to account for the intuition that a traveler is justified in accepting directions from a stranger in a new country, despite lacking specific non-testimonial reasons to trust that stranger.
referencePaul L. Harris authored the chapter "What Do Children Learn from Testimony?" in the 2002 book "The Cognitive Basis of Science," edited by Peter Carruthers, Stephen Stich, and Michael Siegal and published by Cambridge University Press.
claimLocal Reductionism posits that a hearer is justified in accepting a speaker's testimony only if the hearer possesses non-testimonial reasons to believe the speaker is reliable on that specific occasion, rather than relying on a general belief in the reliability of testimony.
claimNon-Reductionists argue that individuals do not need positive reasons to believe a speaker's testimony is reliable in order to be justified in believing that testimony.
claimTestimonial Reliabilism can be interpreted in three ways: focusing solely on the reliability of the speaker's production processes, focusing solely on the reliability of the hearer's consumption processes, or focusing on the reliability of both processes.
formulaThe Transmission View necessity condition (TV-N) states that for every speaker A and hearer B, B knows proposition p on the basis of A's testimony only if A also knows p.
claimEpistemologists generally agree that it is possible to learn from the testimony of others, although explaining the mechanism of this learning process remains a difficult task.
claimThe 'Third Big Question' in social epistemology asks whether a hearer's belief, formed on the basis of a speaker's testimony, is justified by evidence, and if so, what the source of that evidence is.
claimThe objection that Local Reductionism precludes children from learning from parental testimony also applies to Global Reductionism.
perspectiveKenyon (2013) defends Local Reductionism by arguing that hearers can use contextual information to support their inference about a speaker's reliability, even when they know little about the speaker.
claimDaniel Groll and Jason Decker argued in 2014 that moral testimony should be treated similarly to other forms of testimony.
claimJack Lyons examined the relationship between testimony, induction, and folk psychology in a 1997 article in the Australasian Journal of Philosophy.
claimAnti-Individualist Testimonial Reliabilists argue that testimonial justification must be understood through cognitive processes that include both the speaker's production of testimony and the hearer's consumption of that testimony.
claimProponents of the Assurance View maintain that the speech act of telling is central to understanding the relationship between a speaker and their audience, as telling involves a speaker inviting their audience to trust that a proposition is true, effectively guaranteeing the truth of the proposition.
referenceCatherine Z. Elgin published the paper 'Take If from Me: The Epistemological Status of Testimony' in the journal Philosophy and Phenomenological Research in 2002.
claimOpponents of Global Reductionism argue that acquiring non-testimonial reasons to justify the general reliability of testimony leads to either a vicious circle or an insurmountable regress, as confirming the reliability of one speaker often requires relying on the testimony of others.
claimRobert Audi (1997) maintains that while testimony can generate justification, it can only transmit knowledge.
claimKourken Michaelian's 2010 article 'In Defence of Gullibility: The Epistemology of Testimony and the Psychology of Deception Detection' argues for a defense of gullibility within the context of testimony and deception detection.
claimJennifer Lackey addresses the 'infant/child objection' regarding testimony in a 2005 article.
referenceSaul Traiger published the article 'Experience and Testimony in Hume’s Philosophy' in the journal Episteme in 2010.
claimPatrick Rysiew examines the limits of inductivism in relation to testimony and simulation in his 2000 paper published in the Australasian Journal of Philosophy.
formulaThe Transmission View sufficiency condition (TV-S) states that for every speaker A and hearer B, if A knows proposition p, B comes to believe p based on A's testimony, and B has no undefeated defeaters for believing p, then B comes to know p.
referenceMichael Dummett published the paper 'Testimony and Memory' in 1994.
referenceJ. Adam Carter and Philip J. Nickel published the paper 'On Testimony and Transmission' in the journal Episteme in 2014.
procedureTo justify accepting a specific piece of testimony under Local Reductionism, a hearer must possess non-testimonial evidence supporting two premises: (1) the speaker made the specific statement, and (2) the speaker is generally truthful in that specific context and domain.
claimProponents of the Assurance View of testimony argue that when a speaker tells an audience that a proposition p is true, the speaker is assuring the audience that p is the case, thereby establishing an interpersonal relationship between the speaker and the audience.
claimRecent epistemological research on whether testimony generates or transmits knowledge focuses on distinguishing between different versions of TV-N and TV-S to determine which versions avoid specific epistemic problems.
referenceCrispin Wright's hybrid view of testimonial justification suggests that a hearer's belief can be justified by the hearer's own evidence for accepting what the speaker says, the reliability of the speaker's testimony, or by inheriting the evidence possessed by the speaker.
claimTestimony is an indispensable source of knowledge regarding history, science, politics, and other people, though the mechanism of how individuals learn from a speaker's testimony remains a subject of philosophical debate.
claimLocal Reductionism precludes young children from being able to learn from the testimony of their parents.
accountIn the scenario where a stranger testifies that a favorite team won a game, it is unclear whether a hearer is justified in believing the testimony because the hearer does not know if the stranger typically speaks the truth, even if there is no specific reason to doubt the statement.
perspectiveGoldberg and Henderson (2006) argue that for a hearer to be justified in believing testimony, they must not only lack undefeated defeaters but also be counterfactually sensitive to the presence of defeaters in their environment.
claimThe disjunctive account of testimony captures both the intentional act performed by a speaker and the sense in which testimony serves as a source of knowledge and justified belief regardless of the speaker's original intent.
referenceElizabeth Fricker discussed the concept of knowing through being told in a 2004 handbook entry.
referenceStephen Wright authored several works on knowledge transmission, including the articles 'In Defence of Transmission' (2015), 'Circular Testimony' (2016), 'The Transmission of Knowledge and Justification' (2016), 'Sincerity and Transmission' (2016), and the book 'Knowledge Transmission' (2019).
referenceRichard Moran's 2018 book 'The Exchange of Words: Speech, Testimony, and Intersubjectivity' explores the relationship between speech, testimony, and intersubjectivity.
claimNon-Reductionists argue that humans are naturally endowed with dispositions to tell the truth, believe what they are told, and detect when a speaker is untrustworthy.
claimOpponents of Non-Reductionism argue that the theory is false because it rejects the requirement for positive reasons to trust testimony, thereby permitting hearers to be irrationally gullible.
procedureGraham (1997) defines testimony as: S testifies that p if and only if (i) S's stating that p is offered as evidence that p, (ii) S intends that his audience believe that he has the relevant competence, authority, or credentials to state truly that p, and (iii) S's statement that p is believed by S to be relevant to some question that he believes is disputed or unresolved and is directed at those whom he believes to be in need of evidence on the matter.
procedureCoady (1992) proposes that S testifies that p if and only if: (T1) S's stating that p is evidence that p and is offered as evidence that p; (T2) S has the relevant competence, authority, or credentials to state truly that p; and (T3) S's statement that p is relevant to some disputed or unresolved question and is directed to those who are in need of evidence on the matter.
perspectiveCritics of Global Reductionism argue that it is a mistake to treat testimony as a unified, homogeneous category of knowledge, because the reliability of testimony varies significantly depending on the subject matter, such as the difference between music preferences and political opinions.
claimReductionists have developed responses to the objections regarding children's testimony, the justification of testimony from strangers, and the difficulty of testimonial justification based on social psychology.
claimJohn MacFarlane discussed knowledge laundering, testimony, and sensitive invariantism in a 2005 article in Analysis.
claimOpponents of Local Reductionism argue that the theory problematically excludes young children from justifiably accepting parental testimony because children lack the worldly experience required to establish the reliability of their parents.
claimTestimonial Reliabilists define testimonial justification as the reliability of the processes involved in both the production and consumption of testimony.
referenceJoseph Shieber provides a philosophical introduction to the topic of testimony in his 2015 book 'Testimony: A Philosophical Introduction'.
perspectiveA primary motivation for Non-Reductionism is to avoid the difficulty of acquiring testimonial knowledge that arises if hearers are required to have positive reasons for believing a speaker's testimony is reliable.
referenceJennifer Lackey's hybrid view of testimonial justification posits that justification consists partly in the hearer's evidence for accepting the speaker's testimony, and partly in the reliability of the speaker and hearer at producing and consuming testimony respectively.
claimJohn McDowell discussed knowledge by hearsay in a 1994 chapter included in the book 'Knowing from Words: Western and Indian Philosophical Analysis of Understanding and Testimony'.
perspectiveThomas Reid (1983) argues that whatever reasons exist for considering perception a basic source of justification also apply to testimony as a basic source of justification.
accountIn the 'Persistent Believer' case, Persia ignores her eye doctor Eyal's (incorrect) testimony that her vision is unreliable, sees a badger, and forms a true belief about the badger. Persia then tells her friend Fred about the badger. Because Fred is unaware of Eyal's misleading testimony and has reason to trust Persia, Fred acquires knowledge of the badger's presence based on Persia's testimony, even though Persia herself lacked justification for her belief due to the undefeated defeater provided by Eyal.
claimThe 'Second Big Question' in epistemology asks whether testimony can generate knowledge or merely transmit it, specifically whether a hearer can acquire knowledge from a speaker who does not know the proposition themselves.
claimOpponents of Global Reductionism argue that justifying the general reliability of testimony requires individuals to independently verify a vast number of facts, which is practically impossible due to time and resource constraints.
claimDavid Owens' 2006 article 'Testimony and Assertion' investigates the relationship between testimony and the act of assertion.
claimAnna-Sara Malmgren investigated whether there is a priori knowledge by testimony in a 2006 article in The Philosophical Review.
claimArnon Keren explores the relationship between epistemic authority, testimony, and the transmission of knowledge in a 2007 article.
claimJordan Howard Sobel provides a Bayesian interpretation of David Hume's analysis of the evidence of testimony for miracles in his 1987 paper published in The Philosophical Quarterly.
procedureAccording to Hinchman (2005), a speaker (S) tells an audience (A) that a proposition (p) is true if and only if A recognizes that S, in asserting that p, intends: (i) that A gain access to an epistemic reason to believe that p, (ii) that A recognize S's intention (i), and (iii) that A gain access to the epistemic reason to believe that p as a direct result of A's recognition of S's intention (ii).
claimDavid Owen's 1987 article 'Hume versus Price on Miracles and Prior Probabilities: Testimony and the Bayesian Calculation' compares the views of Hume and Price on miracles, testimony, and Bayesian probability.
claimEpistemologists debate whether testimony is a basic source of justification or if it can be reduced to other epistemic sources like perception, memory, and inference.
claimThe debate between individualism and anti-individualism in testimony concerns whether testimonial justification depends entirely on the listener's internal factors or partially on factors related to the speaker.
claimLocal Reductionism implies that humans have less testimonial justification than previously assumed, because it requires hearers to be skilled at monitoring for signs of falsehood and unreliability, a skill humans lack.
claimGoldberg (2010b) argues that asserting that p is not a necessary condition for testifying that p.
claimKeith Lehrer discussed testimony and trustworthiness in a 2006 chapter published in the book 'Testimony and Trustworthiness'.
claimKourken Michaelian's 2013 article 'The Evolution of Testimony: Receiver Vigilance, Speaker Honesty and the Reliability of Communication' examines the evolutionary aspects of testimony, focusing on receiver vigilance and speaker honesty.
referenceSaul Traiger published the article 'Humean Testimony' in the Pacific Philosophical Quarterly in 1993.
claimThe central question in the debate over testimonial justification is whether testimony is a basic source of justification or if it can be reduced to a combination of other epistemic sources.
claimNon-Reductionists endorse the 'Presumptive Right,' which states that a hearer is justified in believing a speaker if the hearer does not possess an undefeated defeater indicating the testimony is false or unlikely to be true.
claimWhile it is generally accepted that one can acquire justification for empirical beliefs (e.g., that a taco truck is open) via testimony, it is debated whether one can acquire justification for moral or aesthetic beliefs (e.g., that an action is morally wrong or that a mural is beautiful) solely through testimony.
claimA testimonial exchange involves two distinct processes: the production of the speaker's testimony, which relates to the likelihood the speaker tells the truth, and the hearer's consumption of the testimony, which relates to the hearer's ability to monitor for signs of falsehood.
perspectiveE. Fricker (1995) argues that testimony should be understood in a general sense with no restrictions on the subject matter or the speaker's epistemic relation to the subject matter.
claimE. Fricker (1995) and Lackey (2008) object to Coady's condition T1, arguing that one can testify that p even if the testimony provides the hearer with no evidence that p is true, such as when a speaker is known to be unreliable.
claimLocal Reductionism avoids the vicious circles and regresses associated with Global Reductionism because it does not require third-party testimony to establish the reliability of a speaker.
claimSteven L. Reynolds argues about the relationship between testimony, knowledge, and epistemic goals in his 2002 paper published in Philosophical Studies.
claimPeter J. Graham argued in 2000 that testimony functions as a mechanism for transferring knowledge between individuals.
claimElizabeth Fricker and Ernest Sosa defend the position that testimony should be identified with assertion, meaning one testifies that a proposition is true if and only if one asserts that the proposition is true.
claimLocal Reductionists do not require a listener to have positive reasons for the general reliability of testimony to be justified in accepting a specific speaker's statement.
claimCharlie Pelling's 2013 article 'Testimony, Testimonial Belief, and Safety' examines the relationship between testimony, testimonial belief, and the concept of safety in epistemology.
claimMichael Root analyzes David Hume's views on the virtues of testimony in his 2001 paper published in the American Philosophical Quarterly.
claimReductionists define the condition for justified belief in testimony as follows: a hearer is justified in believing a speaker if and only if the hearer has positive reasons to believe the testimony is reliable (where these reasons are not based on testimony) and the hearer possesses no undefeated defeaters indicating the testimony is false or unlikely to be true.
referenceErnest Sosa authored the essay 'Testimony and Coherence,' which was published in the 1994 collection 'Knowing from Words,' edited by Bimal Krishna Matilal and Arindam Chakrabarti.
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claimTestimonial reductionism asserts that individuals are justified in believing testimony only if they possess testimony-independent evidence, such as sensation, introspection, or memories of sensation or introspection, to support that belief.
claimThe epistemology of disagreement is distinct from the epistemology of testimony because not all evidence from disagreement is testimonial; for example, one can infer disagreement by observing another person's behavior.
claimTestimonial reductionism posits that an individual is justified in believing a speaker's testimony that a proposition is true if and only if the individual receives the testimony, possesses inductive evidence based on observation for the reliability of that testimony, and the proposition is not defeated by other evidence.
claimTestimony is defined as any utterance (e.g., speaking, writing, signing, etc.) by which the actor intends to communicate that a proposition p is true.
claimRowley (2016) argues that the two-step reductionist solution implies that a speaker's testimony that a proposition is true provides the listener with evidence in support of that proposition, even without the listener receiving the speaker's original evidence.
referenceRowley (2016) suggests that simple explanations available to young children may justify the belief in testimony, potentially addressing the Inductive Challenge to Others (ICO).
referenceShogenji (2006) argues that the reliability of testimony is tacitly confirmed as children learn to associate words, contexts of utterance, and truth.
claimEpistemic democracy investigates whether collective opinion is more likely to yield truth than individual opinion, whether votes can be construed as testimony about the best candidate or policy, and whether democracy can be justified on epistemic grounds.
referencePhilosophers define testimony as the act of telling others about the world, which can take the form of speech, text, or other communication methods, as noted by Jennifer Lackey in 2006.
claimReductionism in the epistemology of testimony posits that testimony justifies belief because individuals learn through observation that testimony correlates with truth, similar to how one learns that smoke is caused by fire.
claimPeter Graham proposes a non-reductionist view where undefeated testimony that a proposition is true provides some reason to believe it, even if that testimony does not constitute sufficient evidence for belief.
claimA widespread attitude in epistemology is that there is a large class of testimony, such as gossip, rumors, tabloid headlines, and conspiracy theories, that individuals should be disposed to dismiss.
perspectiveNon-reductionists argue that Miranda Fricker's objection regarding gullibility fails because monitoring for the trustworthiness of testimony does not need to be conscious, but can be unconscious and automatic.
claimTestimonial justification reduces to other forms of justification, such as observation and memory, because testimony is only considered evidence when supported by inductive evidence.
claimNon-reductionism regarding testimony is the view that a person S is sometimes justified in believing testimony p even when S lacks testimony-independent evidence that the testimony is reliable.
formulaAccording to non-reductionism, an individual is justified in accepting a speaker's testimony that a proposition (p) is true if and only if the individual receives the testimony that p and the proposition p is undefeated.
claimThomas Reid's argument, known as the 'not enough evidence objection' (NEEO), posits that reductionism implies individuals are rarely justified in believing testimony, which serves as a powerful objection to non-skeptical reductionism.
claimThe reductionist view of testimony asserts that a person S1 is justified in believing a person S2's testimony that p if and only if S1 receives the testimony, S1 has inductive evidence based on observation that S2's testimony is reliable, and the proposition p is not defeated by other evidence S1 possesses.
perspectiveThe most effective strategy for non-reductionists is to provide an account of testimony as evidence that is both independently plausible and permissive enough to classify testimony as a non-reducible form of evidence.
claimReductionists can potentially treat experiences of testimony, communication, and social interactions as data, where the best explanation is that many individual cases of testimony are true.
claimWhen an individual recognizes that a disagreeing party is more likely to be correct regarding a proposition, the individual should treat the other party's belief as testimony and adopt that belief.
claimNon-reductionism faces a phenomenalistic problem because, unlike other sources of justification such as perception, introspection, memory, or intuition, testimony does not inherently present itself as true.
referenceThe work 'Knowing from Words: Western and Indian Philosophical Analysis of Understanding and Testimony', edited by Bimal K. Matilal and Arindam Chakrabarti in 1994, compares Western and Indian philosophical perspectives on testimony.
perspectiveMiranda Fricker argues that non-reductionism licenses gullibility because it involves a presumptive right to trust testimony without requiring vigilance regarding the trustworthiness of that testimony.
claimTestimony differs from other sources of justification because it does not inherently 'wear its truth on its sleeve,' functioning more like an inference (such as concluding there is a fire upon seeing smoke) rather than an immediate presentation of truth.
claimReductionism explains the justification for relying on testimony through a familiar form of inductive justification, which provides it a theoretical advantage over non-reductionism.
claimThe Evidence of Evidence Principle suggests that discovering an expert believes a proposition within their area of expertise constitutes strong evidence for that proposition, often stronger than any competing evidence a novice possesses.
claimAn individual has stronger than usual justification to believe a speaker's testimony if the speaker is known to be honest and knowledgeable about the topic, whereas an individual is generally not justified in believing testimony from someone known to be prone to lying.
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referenceIn the Islamic tradition, the authenticity of hadith—reports of the sayings and doings of the prophet Mohammed—relied on verification of each link in a multigenerational chain of testimony, ensuring every memorizer in the chain was honest and reliable (Şentürk, 2005).
claimEpistemologists hold differing views on whether testimony is a basic source of knowledge, similar to perception or logical reasoning, or a composite type of knowledge that combines perception and inference.
claimThe trustworthiness of an individual can vary based on context, such as the difference between providing testimony in a courtroom under the threat of perjury versus in a personal interaction.
claimThe fundamental question of social epistemology concerns whether, how much, under what conditions, and in what manner individuals ought to trust the testimony of others.
claimKristie Dotson defines smothering as a form of testimonial injustice where speakers self-silence due to the fear that their words will be misconstrued in a way that causes harm to themselves or their marginalized community.
claimJosé Medina argues that credibility deficits are better understood in triadic contexts rather than dyadic ones, as testimony regarding marginalization is often met with denial or discrediting from individuals in dominant social positions.
claimIn the context of cumulative culture passed down through generations, testimony is conceived as a basic source of knowledge.
claimWhen someone offers testimony, there is a general expectation that they are able to survey their own reasoning, transfer it to others via explanation, and detect and trace flaws in it when these are pointed out.
claimThere is a philosophical debate regarding whether testimony is a basic source of knowledge, similar to perception or logical reasoning, or a composite type of knowledge that combines perception and inference.
claimIn the works of Coady, Goldman, Fuller, Kitcher, and Craig, the trustworthiness of testimony is analyzed in contexts ranging from lay conversations to specialized environments like news reporting, courtrooms, and academic publications.
claimIn the context of testimonial injustice, 'silencing' occurs when a speaker is not taken seriously as a potential knower in the first place, rendering them unable to offer testimony.
claimGaslighting undermines a person's epistemic agency by causing the individual to doubt their own perceptual, memorial, agential, or cognitive capacities, resulting in a loss of confidence required to offer testimony.
claimNancy Hartsock introduced the notion of standpoint epistemology in 1983, which posits that socially marginalized people who engage in political activism are especially likely to acquire knowledge of the conditions of their marginalization, making their testimony valuable.
claimThomas Reid argued for the principle of credulity, which asserts the right to trust the word of others.
claimSocial epistemologists generally agree that context influences the trustworthiness of testimony by shaping the concerns, patterns of attention, and incentives of the interlocutors.
claimAlvin Goldman describes the 'two-expert problem' as a triadic context where a non-expert must decide which of two disagreeing experts to trust, noting that trusting one necessarily requires mistrusting the other.
claimTestimony is defined as an epistemic interaction where individuals communicate information to others and ask them to take their word for it, requiring trust.
claimTestimony is generally expected to involve the testifier surveying their own reasoning, transferring it to others via explanation, and detecting and tracing flaws in that reasoning when pointed out.
claimKristie Dotson defines silencing as a form of testimonial injustice where a speaker is not taken seriously as a potential knower, preventing them from being in a position to offer testimony.
procedureAlvin Goldman and Hugo Mercier suggest that while there is no surefire way to resolve the two-expert problem, non-experts can use heuristics such as testing for plausibility, observing track records, checking for conflicts of interest, looking for broader consensus, and verifying credentials from respected institutions.
claimMiranda Fricker defines testimonial injustice as occurring when someone gives less credence to the testimony of another person due to identity-based prejudices such as misogyny, racism, or classism.
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perspectiveSome scholars, including Freiman and Miller (2020) and Freiman (2023), argue that AI-produced reports should be considered testimony and that the epistemology of testimony should be extended to include them.
claimTestimony emerged as a central topic for social epistemology due to the works of Elizabeth Fricker (1987), Edward Craig (1990), and C.A.J. Coady (1992).
claimKatie Steele's 2012 paper 'Testimony as Evidence: More Problems for Linear Pooling' identifies specific logical challenges associated with using testimony as evidence within linear pooling frameworks.
referenceNick Leonard examines the relationship between testimony, evidence, and interpersonal reasons in his 2016 paper 'Testimony, evidence and interpersonal reasons'.
claimReductionism in epistemology is the view that the justification of beliefs derived from testimony can be reduced to justifications provided by other sources such as perception, memory, and induction.
claimRussell et al. (2015) argue that social epistemology approaches focusing on individual topics of interest when addressing peer disagreement and testimony require a holistic approach to aggregation.
referenceFormal epistemology uses proof-based methods to address questions of knowledge acquisition within a community, including topics like judgment aggregation and testimony.
claimC. A. J. Coady provided a philosophical study of testimony in his 1992 book 'Testimony: A Philosophical Study'.
perspectiveSome scholars, such as Goldberg (2020), deny that AI-produced sentences constitute testimony because they define testimony as a speech act for which a speaker must bear responsibility.
claimJessica Brown proposes an account of group justification that appeals to the testimony of group members but does not require the beliefs expressed in those testimonies to be justified for the group's belief to be justified, thereby avoiding objections raised by Jennifer Lackey against Alvin Goldman.
claimIn the context of social epistemology, testimony is defined as an act where one agent (a speaker or writer) reports information to an audience, and the audience acquires a 'testimony-based' belief by accepting the report on the speaker's authority.
claimSocial epistemologists are increasingly examining the role of technology in testimony, specifically questioning how the multi-author nature of Wikipedia entries affects the epistemology of beliefs formed based on them.
claimTheories that deny testimony is a basic source of justification argue that testimony-based beliefs are only justified if the audience possesses adequate independent reasons to consider the speaker trustworthy.
claimAnti-reductionism is the view that testimony is a basic source of justification, meaning testimony-based beliefs are justified as long as the audience has no reasons for doubt.
claimTyler Burge argued in his 1993 paper 'Content Preservation' that testimony functions as a mechanism for preserving knowledge content.
referenceTim Kenyon published 'The Informational Richness of Testimonial Contexts' in The Philosophical Quarterly in 2013.
referenceFrederick F. Schmitt's 2006 paper 'Testimonial Justification and Transindividual Reasons' explores how testimony provides justification for belief.
claimThe problems of belief aggregation, peer disagreement, and testimony are entangled because if a rational group adopts an aggregated belief, it may be rational for an individual in that group to adopt the same belief after learning the credences of their peers.
claimFormal epistemology literature addresses four key questions: 1) how should a group aggregate their judgements? 2) how should a group aggregate their fine-grained beliefs? 3) how should Bayesians update on the testimony of others? and 4) what sorts of aggregation methods create rational or effective groups?
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accountThe terrorist attack in Sharm el-Sheikh on July 22, 2005, killed at least 88 people, a fact learned by the public through testimony such as reports in the Washington Post.
claimThe concept of 'saying that p' in the context of testimony includes ordinary daily utterances, blog posts, journalistic articles, and information delivered via television, radio, tapes, and books.
claimThomas Reid suggested that humans have a natural tendency to accept testimonial sources as reliable and to attribute credibility to them unless there are specific reasons to believe otherwise.
claimThe necessary truth approach to justifying testimony faces the difficulty that one cannot acquire knowledge from sources whose reliability is unknown.
claimTestimony is a source of knowledge that is not distinguished by having its own cognitive faculty; rather, acquiring knowledge through testimony involves coming to know a proposition on the basis of someone else stating that proposition.
claimFor true beliefs to qualify as knowledge, they must originate from sources considered reliable, which include perception, introspection, memory, reason, and testimony.
claimFor a belief to qualify as knowledge, it must originate from sources considered reliable, such as perception, introspection, memory, reason, and testimony, rather than psychological factors like desires, emotional needs, prejudice, or biases.
claimThe track record approach to justifying testimony is one method, but an alternative is declaring it a necessary truth that trust in testimonial sources is justified.
perspectiveExternalists argue that testimony is a valid source of knowledge if and only if the information comes from a reliable source.
Epistemology (Stanford Encyclopedia of Philosophy/Fall 2019 Edition) plato.stanford.edu Dec 14, 2005 6 facts
claimThe breadth of knowledge derived from testimony raises the question of whether personal experience provides a sufficient evidence base to justify the reliability of all testimonial sources.
accountLearning about the July 22, 2005 terrorist attack in Sharm el-Sheikh, which killed at least 88 people, by reading the Washington Post is an example of acquiring knowledge through testimony.
claimThe proposal that trust in testimonial sources is a necessary truth faces the challenge that knowledge cannot be acquired from sources whose reliability is unknown.
claimTestimony is distinguished from other sources of knowledge because it does not rely on a specific cognitive faculty, but rather involves acquiring knowledge that p on the basis of someone saying that p.
claimOne argument for the reasonableness of trusting testimony is that individuals accumulate a long track record of personal experiences with testimonial sources that serves as a sign of reliability.
claimThe epistemological puzzle regarding testimony is determining why testimony serves as a source of knowledge.
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referenceRobert Audi authored 'Testimony, Credulity, and Veracity' for the 2006 book 'The Epistemology of Testimony'.
claimGaṅgeśa (14th-century India) developed a reliabilist theory of knowledge and considered the problems of testimony and fallacies.
claimAncient Indian philosophy examines different sources of knowledge, referred to as pramāṇa, with most schools discussing perception, inference, and testimony as sources.
claimJustification by testimony relies on information one person communicates to another, which can occur through talking or through other forms such as letters, newspapers, and blogs.
claimEpistemologists investigate sources of justification, including perception, introspection, memory, reason, and testimony, to discover how knowledge arises.
claimSources of justification are cognitive capacities or methods through which people acquire justification, with commonly discussed sources including perception, introspection, memory, reason, and testimony.
Epistemology | Internet Encyclopedia of Philosophy iep.utm.edu 5 facts
claimReliabilism identifies sources of belief formation such as sense experience, reason, testimony, and memory, and emphasizes the cognitive process that leads to a belief's formation.
claimReliabilism evaluates beliefs by identifying the specific cognitive process that led to their formation, such as the specific sense used, the source of testimony, the type of reasoning, or the recency of a memory.
claimKnowledge can be transmitted between individuals through testimony, where a person's justification for a belief is based on a trusted source confirming its truth.
claimReliabilism, a prominent version of externalism, suggests that the justification of a belief depends on the source of that belief, such as sense experience, reason, testimony, or memory.
claimUsing vision to determine the color of a well-lit, nearby object is a reliable belief-forming process for a person with normal vision, whereas forming beliefs based on the testimony of compulsive liars is not a reliable process.
Virtue Epistemology - Stanford Encyclopedia of Philosophy plato.stanford.edu Jul 9, 1999 4 facts
claimIslamic philosophy contains precursors to contemporary virtue epistemology, specifically in al-Kindī and al-Fārābī's discussions on the epistemic value of imagination and Avicenna's social epistemology regarding testimony.
claimWayne Riggs (2009) argues that if Morris were asked about the tower's location shortly after receiving testimony, he would be out of line to assert the location as fact, which suggests he does not actually possess knowledge.
claimJohn Greco argues that intellectual virtues are often social virtues exercised in social environments, such as social-cognitive abilities used to assess speaker competence and sincerity in testimony.
claimWayne Riggs (2009) argues that it is unclear if Morris knows the location of the tower, suggesting that casual, unreflective acceptance of testimony should not necessarily count as knowledge.
Understanding epistemology and its key approaches in research cefcambodia.com Jan 21, 2023 2 facts
claimTestimony as a source of knowledge is distinct from other cognitive faculties because it relies on information provided by others through media such as news articles, TV, radio, and books.
procedureTo avoid false testimony, Pritchard (2018) advises that individuals should scrutinize, compare, and evaluate received testimony against other testimony or reliable sources.
Epistemology - Stanford Encyclopedia of Philosophy plato.stanford.edu Dec 14, 2005 1 fact
accountLearning the time by asking a person and receiving an answer is an example of acquiring knowledge through testimony.
Social Epistemology - Stanford Encyclopedia of Philosophy plato.stanford.edu Feb 26, 2001 1 fact
claimGlobal reductionism holds that for a listener to justifiably accept a speaker's report, the listener must possess non-testimonially based positive reasons to believe that testimony is generally reliable.
Wikipedia and the Epistemology of Testimony | Episteme cambridge.org Jan 3, 2012 1 fact
claimThe author of the paper 'Wikipedia and the Epistemology of Testimony' aims to determine whether Wikipedia is a source of testimony, the nature of that source, and how to assess the trustworthiness of Wikipedia as an epistemic source.
Social Epistemology - Stanford Encyclopedia of Philosophy plato.stanford.edu Aug 28, 2019 1 fact
perspectiveC.A.J. Coady argues against global reductionism, asserting that the observational basis of ordinary epistemic agents is too limited to support an inductive inference regarding the general reliability of testimony.
Social epistemology - Routledge Encyclopedia of Philosophy rep.routledge.com 1 fact
claimSocial epistemologists have extensively studied testimony, expert testimony, and peer disagreement.
Group Testimony: Social Epistemology - Taylor & Francis tandfonline.com 1 fact
claimThe fact that individuals gain much of their knowledge through the testimony of others challenges the philosophical position of epistemic individualism.
The Debate on Testimony in Social Epistemology and Its ... - MDPI mdpi.com Mar 7, 2019 1 fact
claimBelief based on testimony is often epistemically superior to belief based on entirely direct, non-testimonial evidence.