Axel Gelfert

This paper critically examines a foundational narrative in the analytic epistemology of testimony. Despite the widespread claim that testimony was historically neglected, contemporary epistemologists frequently invoke two supposed predecessors representing opposing positions: anti-reductionism (or credulism), which treats testimony as an autonomous source of knowledge, and reductionism, which grounds testimonial justification in perception, memory, and inductive inference. David Hume is commonly regarded as the paradigmatic reductionist, allegedly requiring individuals to base testimonial belief on first-hand empirical evidence of a speaker’s reliability or the probability of the reported content. According to this standard interpretation, Hume seeks to reduce testimonial justification globally to individual cognitive resources. This paper challenges that reading and advances an alternative interpretation. It argues that Hume’s account, while broadly empirical, is not individualistically reductionist. Hume neither demands global verification of testimony nor insists on constant scrutiny for defeaters. Rather, acceptance of testimony typically constitutes a justified default response, grounded globally in our empirical knowledge of the social world, which does not require case-by-case empirical support for each case of testimony separately. The paper first reconstructs the standard interpretation and traces the sources of its persistence, then develops connections to virtue epistemology, and finally situates testimony within Hume’s broader theory of human nature. The resulting interpretation repositions Hume as an important precursor to philosophical approaches that are favourable to the acceptance of testimony as a source of knowledge.

Mathematical actions and activities, I wish to argue in this paper, are typically mediated by symbol systems, notations, and formalisms, in a way that not only allows for the seamless expression of mathematical concepts, but also actively shapes mathematical practice, both at the level of individual derivations and at the collective level of mathematics as a discipline. That is, notations and formalisms do not play a merely auxiliary role, in that they give neutral expression to the underlying foundational concepts, but they are themselves constituents of mathematical practice, without which certain connections and developments within mathematics (and certain ways of applying mathematics to the natural world) would not be possible. I shall highlight four areas where one might fruitfully look for epistemic actions in the course of studying mathematical practice. The four examples in question are the use of gestures and other anticipatory bodily movements (in particular in instructional settings), the application of material models to mathematics, the initially puzzling disciplinary practice of re-proving theorems (which, after all, should be epistemically redundant), and—finally—the creation of collectively shared symbolic and notational resources. As I shall argue, it is the latter example—the emergence of mature notational formalisms—which leads to a partial vindication of symbol use as a type of epistemic action, provided we make a slight (though well-motivated) modification of the very notion of epistemic action in question.

The term ‘fake news’, it is argued in this chapter, captures a novel kind of social-epistemic dysfunction that arises from _systemic_ distortions of established processes of creating, disseminating, and consuming news-like content. Navigating informational environments populated by fake news requires the cultivation of epistemic routines that reduce our exposure to misleading and deceptive information, while at the same time continuing to allow us to partake in the collective growth of knowledge. Shifting the focus to epistemic routines steers a middle path between two frequently encountered dichotomous responses to the problem of fake news: viz., between emphasizing the individual’s responsibility to ‘think critically and check one’s sources’ and advocating technological tweaks (such as automated fact-checking). While epistemic agents ought to be held responsible for the epistemic routines they commit themselves to, there is also a collective need for making the predictable effects of such choices transparent to individuals, wherever technologically possible.

Kant ist sich der Vielschichtigkeit von Irrtum, Schein und Täuschung ebenso bewusst wie der Notwendigkeit, zwischen verschiedenen Formen und Funktionen derselben zu unterscheiden. So hält Kant 1777 in einer Opponentenrede im Rahmen einer öffentlichen Disputation seinem neu ernannten Kollegen Johann Gottlieb Kreutzfeldt, Professor der Dichtkunst, vor, in seiner Habilitationsschrift, die eine Brücke zwischen poetischen Vorstellungen und Erzählungen einerseits und Sinnestäuschungen andererseits schlagen will, rechne „der Verfasser vieles zu den Sinnestäuschungen, was, wie mir erscheint, ganz und gar nicht dazu gehört: die Magie, die Wahrzeichendeutung, die Astrologie etc.“. Hier gelte es zu unterscheiden – zwischen den verschiedenen Formen, aber auch den je nach Kontext unterschiedlichen epistemischen Auswirkungen des Scheins. Denn es ist durchaus nicht so, dass der Schein uns zwangsläufig in die Irre führen muss. Einerseits haben wir als Erkenntnissuchende die Möglichkeit, uns durch tätige Vernunftausübung gegen den täuschenden Einfluss des Scheins zu wappnen; andererseits kommt es immer dann, wenn wir mit anderen in kognitiven Austausch treten, auch auf die Gegenseite an. Kaum zu bestreiten ist dabei, dass zentrale Begriffe wie „Täuschung“ und „Leichtgläubigkeit“ paradigmatisch auf die intuitionsstiftende Grundkonstellation des kommunikativen Austauschs mit anderen angewiesen sind. Wir irren uns nicht nur, sondern täuschen einander auch. Im Umkehrschluss können andere uns bisweilen aber auch vor dem Abgleiten in die Gefilde der Täuschung bewahren, selbst dann, wenn sie die Bedingungen dafür – den Schein – selbst geschaffen haben.

Durch den Fokus auf die epistemische Negativität kann Kants Transzendentalphilosophie noch einmal aus einem anderen Blickwinkel begriffen werden. Die Autor:innen leuchten in ihren Beiträgen wesentliche Facetten der komplexen Strukturen falschen Denkens aus und schaffen damit eine Grundlage, von der aus sich Negativität als erkenntnistheoretischer Grundzug von Kants Systematik verstehen lässt. Dabei widmen sich die Beiträge selten diskutierten Quellen, wie etwa Kants Inauguraldissertation, der Amphibolie der Reflexionsbegriffe, den handschriftlichen,,Reflexionen" und den Vorlesungsnachschriften, da Kant hier seine Theorien des Vorurteils, Irrtums und Scheins entwickelt. So eröffnet dieser Band einen sowohl historischen als auch systematischen Zugang zu Kants Theorie der epistemischen Negativität und lässt Kants,,Revolution der Denkungsart", die die Klassische Deutsche Philosophie einleitet, auch in Bezug zu Vorläufern und zu ihrem Nachwirken in einem neuen Licht erscheinen.

In contemporary epistemology, ‘testimony’ serves as an umbrella term to refer to all those instances where we form a belief on the basis of being told. Like other epistemic sources—perception, memory, inference, introspection—testimony furnishes us with much of what we take ourselves to know; unlike them, however, it depends also on the mental operations of another person (e.g., the eyewitness’s sense perception, the speaker’s intention to share knowledge with us, etc.). Much of the philosophical debate about testimony and the epistemic status of testimony-based beliefs stems from this tension. Reductionists take the evident dependence of testimony-based beliefs on sense perception (e.g., hearing, reading) to be a sign of their derivativeness, as far as their epistemic justification is concerned. Anti-reductionists, by contrast, argue that the speaker’s act of testifying itself confers justification on the hearer’s corresponding belief. Reductionist and anti-reductionist intuitions combine with externalist and internalist leanings to generate a complex taxonomy of philosophical positions. The present chapter surveys these positions and analyses resonances and interferences between them, paying special attention to hybrid positions that combine insights from both ends of the spectrum. One such position that is developed in some detail posits a dual role of abductive considerations in the justification and management of our testimony-based beliefs.

Scientific modeling is an indispensable part of contemporary scientific practice. Yet as a separate, identifiable methodology, it did not enter the scientific toolbox until the 19th century. The present chapter surveys how scientific modeling rose to such a prominent place within scientific practice. It does so by reflecting on its historical origins and on the various (representational and non-representational) uses and functions of scientific models. Modeling as a practice, it is argued, consists of a number of component activities that are neither necessitated by the demands of representationalism nor can be easily assimilated to anti-representationalist versions of instrumentalism. Drawing on practice-based accounts within the philosophy of technology, the chapter concludes that much of the value that modeling holds for science derives from the way it allows us to move back and forth between different intentionality relations, i.e., different ways of relating to the world with, and through, scientific models.

This chapter gives an overview of the main historical developments and systems of logic in the Western tradition, with a focus on the use of specialist terminology and notation in modern logic. Reviewing a number of historical shifts, the chapter shows how the development of logic reflects the intertwinement of logic,language, and notational systems. Notations and the logical systems they express allow for some of the cognitive load of reasoning to be externalized. In this regard, notations function as a toolbox of cognitive technologies and also enable more collaborative ways of working through logical problems. Yet, their development also depends on the material conditions of inquiry, which suggests that notational advances are also impacted by related technological changes, such as the printing press and, more recently, advanced digital tools.

How can scientists and science communicators effectively engage the public in times of crisis and in the face of pervasive uncertainty? Drawing on the experiences of the Covid-19 pandemic and the escalating climate crisis, the three essays in this volume examine key dimensions of this challenge. What roles should scientists play in policy-making? How can the spread of fake news in science communication be curtailed? And how can we represent uncertainties in a way that upholds the credibility of scientific knowledge?

The term „science denialism“ is often understood as the active attempt to undermine evidence-based consensus-building by self-declared „sceptics“, who cast excessive doubt on, or engage in outright denial of, established scientific knowledge against their better judgement. However, it has become apparent over the last few years that science denialism is a more multi-faceted phenomenon which can come in degrees of severity and be based on various argumentative mechanisms. The present paper provides an analysis of a hitherto neglected issue in this context: the connection between overly strong trust in technical applications and the playingdown of scientific facts. It might seem counter-intuitive, even inconsistent, to strongly believe in technical applications and at the same time deny the scientific evidence used to develop these applications. Yet, the „technofideism“ that is fostering radical science skepticism is not based on a rational consideration of risks and benefits associated with new technologies. Rather, it is an expression ofaworldview. To cope with cognitive dissonance, proponents of this worldview would rather deny scientific facts than technological promises. Besides providing a theoretical analysis of technofideism and its mechanism, this contribution will use the examples of „geoengineering“ and a historical case-study to discuss the implications of science denialism motivated by technofideism.

Justification Reporting as a mode of science reporting demands that, whenever feasible, science reporters should report appropriate aspects of the nature and strength of scientific justification, or lack thereof, for a reported scientific hypothesis (Gerken 2022). The benefits of such a norm are deemed to be two-fold: First, Justification Reporting is meant to give the audience direct epistemic reasons for accepting the scientific hypothesis; second, it aims at ensuring that audiences do not just absorb scientific claims but also acquire the requisite justifications, thereby promoting better collective understanding of scientific explanations. Yet, by necessity, Justification Reporting must proceed in a simplified manner and should be phrased in layperson’s terms. We argue that the assumption that appropriate simplifications are possible and can be routinely achieved in contexts of science reporting is optimistic and requires further substantiation. In particular, we look at the issue of oversimplification and its epistemic dangers, and argue that, if attempts to render the presentation of scientific justification appropriate to a given target audience overshoot the mark (due to oversimplification or a misleading framing of the issue at hand), Justification Reporting may fall flat and collapse into one of its competitors, Deficit Reporting and Consensus Reporting.

This paper investigates one of the great achievements of twentieth-century cell biology: determining the structure of the cell membrane. This case differs in important ways from the better-known case of the identification of the DNA double helix as the carrier of genetic information, especially regarding the evaluation of potential evidence in light of prior theoretical commitments. Whereas it has been argued that adherence to a structural hypothesis enabled Watson and Crick to ignore a surplus of (potentially confusing) empirical findings, similar adherence to an elegant and universal structural hypothesis, we argue, unduly shielded the so-called ‘unit-membrane’ model from legitimate challenges on the basis of known phenomena.

While positive appraisals of testimonial knowledge by Enlightenment thinkers have recently begun to receive more attention, such discussions often operate at a very general level, leaving out much of the context and dynamics of specific types of testimonial interactions. Drawing on extended passages from Georg Friedrich Meier and Immanuel Kant, the present paper looks at the specific case of scholarly testimony and the various epistemic dangers that can befall the interaction between scholars (or, in modern parlance, ‘experts’) and lay audiences. While Kant recognises the imperfections of many expert testifiers (and pays special attention to the figure of the ‘pedant’), he is keenly aware of the – greater – risk of what may be called ‘epistemic populism’, which seeks ‘to make imperceptible the blatantly obvious inequality between loquacious ignorance and thorough science’ (AA, XI, 141). Furthermore, Kant suggests, those with superior epistemic authority can justifiably disengage from interactions with those who, as laypersons, arrogate to themselves equal epistemic standing and are unwilling to appreciate the rational force of evidence and argumentation. Prolonging interaction in such a scenario would be futile and may well be ‘contrary to the dignity of reason’ (AA, XI, 143).

That science is more than the unilinear application of general theories to specific empirical circumstances is, one hopes, no longer something that is controversial or requires detailed argument. To be sure, there were times when devising universally applicable theories was seen as the most worthy task of science, with less lofty activities such as experimentation and scientific modeling being relegated to the underbelly of “proper science.” Arguing for a pluralistic recognition of the diversity of scientific practices, methods, and goals, might—at least on the pages of this journal—amount to preaching to the converted. Yet, once the diversity and heterogeneity of science is acknowledged, the real work only starts:...

Whether or not the results of a computer simulation are credible depends to a large extent on the credibilityCredibility of the underlying conceptual model. If a model has been developed explicitly with the goal of running a computer simulation in mind, the two types of credibilityCredibility may seem deeply intertwined. Yet, often enough, conceptual modelsConceptual model predate the subsequent development of simulation techniques, or were first developed outside the context of computer simulation. In such a situation, the specific contribution that a conceptual model makes to the credibility of a simulation requires considerable analysis. How, then, should we assess the credibility of a conceptual model, and which factors ought to playPlay a role in judging whether simulation results derived on its basis are trustworthy? In order to answer these questions, the present chapter begins with the premise that models are never by themselves credible simpliciter, but acquire credibility within a given context of inquiry, which itself depends on the cognitive interests of the inquirer. Judgments concerning the credibility of a conceptual model thus need to be based partly on a characterization of the intrinsic features of the model, partly on the cognitive goals and interests of its users. This realization helps explain why credible models have been variously understood as adequate representations of real-world target systems, as constructions of “credible worlds”Credible world that display internal coherence, and as exploratory tools that may aid our understanding even before a well-developed underlying theory takes shape.

Among contemporary epistemologists of testimony, David Hume is standardly regarded as a ‘global reductionist’, where global reductionism requires the hearer to have sufficient first-hand knowledge of the facts in order to individually ascertain the reliability of the testimony in question. In the present paper, I argue that, by construing Hume’s reductionism in too individualistic a fashion, the received view of Hume on testimony is inaccurate at best, and misleading at worst. Overall, Hume is much more willing to regard testimonial acceptance as a natural response to testimony than has traditionally been thought. In particular, Hume believes that indirect evidence of human nature and of the social world around us, can take the place of first-hand evidence of the track record of individual speakers or specific classes of testimony. In developing this interpretation of Hume’s views on testimony, the present paper draws on discussions found in the Treatise, the Enquiry, and in Hume’s writings on historical knowledge. In der zeitgenössischen Debatte um den erkenntnistheoretischen Status zeugnisbasiertenWissens wird gern auf David Hume als den Urheber eines „globalen Reduktionismus“ verwiesen, demzufolge der Zeugnisempfänger über ausreichend empirische Belege für die Verlässlichkeit des betreffenden Zeugnisses verfügen muss. Im vorliegenden Aufsatz soll gezeigt werden, dass die in der Literatur vorherrschende Meinung ein übertrieben „individualistisches“ Bild von Humes Reduktionismus zeichnet; dadurch wird Humes Position in der gegenwärtigen Debatte ungenau und bisweilen irreführend wiedergegeben. Bei genauerer Betrachtung erweist sich Hume als ausgesprochen aufgeschlossen gegenüber dem Akzeptieren fremden Zeugnisses und sieht darin eine Art Grundmuster im testimonialen Umgang mit anderen. Insbesondere konzediert Hume, dass indirekt erworbenes Wissen um die menschliche Natur und die soziale Welt an die Stelle direkter Belege für die Verlässlichkeit einzelner Zeugen treten kann. Die im vorliegenden Aufsatz entwickelte Neuinterpretation stützt sich auf den Treatise, den Enquiry und auf Humes Schriften zum Problem der historischen Erkenntnis.

Epistemologists of testimony have tended to construct highly stylized (so-called “null setting”) examples in support of their respective philosophical positions, the paradigmatic case being the casual request for directions from a random stranger. The present paper analyzes the use of such examples in the early controversy between reductionists and anti-reductionists about testimonial justification. The controversy concerned, on the one hand, the source of whatever epistemic justification our testimony-based beliefs might have, and, on the other hand, the phenomenology of testimonial acceptance and rejection. As it turns out, appeal to “null setting” cases did not resolve, but instead deepened, the theoretical disputes between reductionists and anti-reductionists. This, it is suggested, is because interpreters ‘fill in’ missing details in ways that reflect their own peculiarities in perspective, experience, upbringing, and philosophical outlook. In response, two remedial strategies have been pursued in recent years: First, we could invert the usual strategy and turn to formal contexts, rather than informal settings, as the paradigmatic scenarios for any prospective epistemology of testimony. Second, instead of “null setting” scenarios, we can focus on richly described cases that either include, or are embedded into, sufficient contextual information to allow for educated judgments concerning the reliability and trustworthiness of the testimony and testifiers involved. The prospects of both of these approaches are then discussed and evaluated.

According to one influential view, model-building in science is primarily a matter of simplifying theoretical descriptions of real-world target systems using abstraction and idealization. This view, however, does not adequately capture all types of models. Many contemporary models in the natural and social sciences – from physics to biology to economics – stand in a more tenuous relationship with real-world target systems and have a decidedly stipulative element, in that they create, by fiat, ‘model worlds’ that operate according to some set of specified rules. While such models may be motivated by an interest in actual target phenomena, their validity is not – at least not primarily – to be judged by whether they constitute an empirically adequate representation of any particular empirical system. The present paper compares and contrasts three such types of models: minimal models, toy models, and exploratory models. All three share some characteristics and thus overlap in interesting ways, yet they also exhibit significant differences. It is argued that, in all three cases, modal considerations have an important role to play: by exploring the modal structure of theories and phenomena – that is, by probing possibilities in various ways – such models deepen our understanding and help us gain knowledge not only about what there is in the world, but also about what there could be.

Traditional frameworks for evaluating scientific models have tended to downplay their exploratory function; instead they emphasize how models are inherently intended for specific phenomena and are to be judged by their ability to predict, reproduce, or explain empirical observations. By contrast, this paper argues that exploration should stand alongside explanation, prediction, and representation as a core function of scientific models. Thus, models often serve as starting points for future inquiry, as proofs of principle, as sources of potential explanations, and as a tool for reassessing the suitability of the target system. This is illustrated by a case study of the varied career of reaction-diffusion models in the study of biological pattern formation, which was initiated by Alan Turing in a classic 1952 paper. Initially regarded as mathematically elegant, but biologically irrelevant, demonstrations of how, in principle, spontaneous pattern formation could occur in an organism, such Turing models have only recently rebounded, thanks to advances in experimental techniques and computational methods. The long-delayed vindication of Turing’s initial model, it is argued, is best explained by recognizing it as an exploratory tool.

In this article we argue that idealizations and limiting cases in models play an exploratory role in science. Four senses of exploration are presented: exploration of the structure and representational capacities of theory; proof-of-principle demonstrations; potential explanations; and exploring the suitability of target systems. We illustrate our claims through three case studies, including the Aharonov-Bohm effect, the emergence of anyons and fractional quantum statistics, and the Hubbard model of the Mott phase transitions. We end by reflecting on how our case studies and claims compare to accounts of idealization in the philosophy of science literature such as Michael Weisberg’s three-fold taxonomy.