Philosophy in Review XXXII (2012), no. 6 468 Sanford C. Goldberg Relying on Others: An Essay in Epistemology. New York: Oxford University Press 2010. x + 217 pages $55.00 (cloth ISBN 978–0–19–959324–8) Over the past two decades there has been an impressive progress in so-called "social epistemology," which is the study of the social dimensions of knowledge and justification. Such a progress is to be explained by the increasing awareness of the narrow approach of traditional epistemology, which is deemed to be too individualistic, in that it assumes that cognitive achievements belong exclusively to the individual believer, thereby ignoring the central part played by others in the acquisition, sustainment, and transmission of knowledge or justified belief. The two main areas of social epistemology are the epistemology of testimony-which deals with epistemic reliance on the testimony of others-and the epistemology of disagreement-which explores the epistemic impact that the opinions of one's dissenters may have upon one's beliefs. Sanford Goldberg is among those who in recent years have contributed the most to the advancement of social epistemology in its two chief areas, but particularly the epistemology of testimony, as made clear in his previous book (Anti-Individualism: Mind and Language, Knowledge and Justification, Cambridge University Press, 2007) and confirmed in the present work. Goldberg's purpose is to lay emphasis on the pervasiveness and ineliminability of our epistemic reliance on others, a reliance which cannot be fully vindicated on the basis of the materials available to the individual subject. He engages not only with epistemological internalism but also with epistemological externalism. For although externalists have recognized that the world is centrally implicated in our knowledge, they are still committed to the ideal of epistemic autonomy, insofar as they focus on the individual knowledge-seeker in isolation from other members of his knowledge community. This explains what may seem a curious fact. Goldberg carries out his project of radically reconsidering the individualistic approach of traditional epistemology from the standpoint of Process Reliabilism (PR), according to which "what makes for doxastic justification and knowledge has to do with the reliability of the type of process (or method) through which a belief is formed and sustained" (12). This externalist view is famously championed by Alvin Goldman, one of the theorists most responsible for the development of social epistemology. However, Goldberg claims that most versions of PR are committed to "Process Individualism" (PI), which is the position according to which "the beliefforming processes relevant to the epistemic assessment of a given belief all take place within the mind/brain of the believing subject herself" (1). Goldberg calls the conjunction of PR and PI "Orthodox Reliabilism," which is the form of reliabilism he seeks to replace. In his view, a proper reliabilist account of at least some of the beliefs formed through epistemic reliance on others also requires an assessment of the reliability of the cognitive processes that take place in their minds/brains. What he wants to establish in the end is that "reliabilist epistemology is ineliminably a social epistemology" (185). In Chapter 1, Goldberg takes issue with what he calls "Knowledge Individualism" (KI), which maintains that all the conditions on knowledge pertain to the knowing subject himself. Philosophy in Review XXXII (2012), no. 6 469 This view faces the problem that, in testimony cases, whether a subject knows through testimony depends upon the reliability of the testimony on which his testimonial belief is based, which in turn (as entailed by the process reliabilist's own understanding of reliability) depends upon the reliability of the relevant cognitive processes that take place in the subject's informant. Goldberg stresses that his view does not imply the so-called "transmission thesis," according to which testimony can only transmit pre-existing knowledge. His claim is only that the "supervenience base of testimonial knowledge includes facts regarding the reliability of the testimony consumed" (21), a claim which holds even if the informant fails to know that which he informs. In Chapter 2 Goldberg argues that, although the Orthodox Reliabilist can and should reject KI, by so doing he would undermine his endorsement of the traditional conception of testimony's epistemic significance-an endorsement which the Orthodox Reliabilist, having embraced PI, is forced to make. According to that conception, the testimonies on which a subject relies are features of his local environment, but although these features may play the role of Gettier conditions and thus undercut the subject's claims to knowledge, this exhausts their epistemic significance. For such features have no bearing upon the doxastic justification of the subject's beliefs, which is to be assessed only by attending to the subject's own cognitive processes. In the next two chapters, Goldberg argues against this conception of the epistemic significance of testimony. In Chapter 3, he offers the initial exposition and defense of the central claim of the book, namely, the "extendedness hypothesis," according to which testimonial belief-formation is a belief-dependent process which takes as its input the testimony of the subject's interlocutor and yields as its output the testimonial belief. Thus, this process includes the cognitive processes taking place not only in the hearer but also in his interlocutor, i.e., it extends to include those processes involved in the production of the testimony. The reliability of the testimony can therefore affect the doxastic justification of the hearer's testimonial belief. Next, in Chapter 4, Goldberg appeals to Goldman's account of the epistemology of memorial belief to show that the extendedness hypothesis is actually a special case of a general principle already endorsed by reliabilists. According to such an account, the assessment of the reliability of a memorial belief includes not only the process of recollection but also the processes involved in the original formation of the belief. Goldberg argues that the reason why the process of memorial belief-sustainment is viewed as extended has to do with the fact that the subject epistemically relies on his past self as an information source. From this he extracts the following general principle: the extent of the subject's epistemic reliance in forming and sustaining a given belief delimits the extent of the cognitive processes that must be assessed in a reliabilist assessment of the doxastic justification of that belief. After addressing at length, in Chapter 5, a number of objections to his view that testimonial belief-formation is an interpersonally extended belief-forming process, Goldberg in Chapter 6 examines a type of belief which, though different from testimonial belief, is also formed through epistemic reliance on others. More precisely, the belief in question is formed via epistemic reliance on the "coverage-reliability" of the subject's community. Unlike testimonial belief, coverage-supported belief does not involve an interpersonally extended belief-forming Philosophy in Review XXXII (2012), no. 6 470 process. Rather, it is formed by means of an inference having as one of its premises what Goldberg calls "the truth-to-testimony conditional": one forms the belief that not-p on the basis that (i) if p were true, one would have heard about it by now, and (ii) one has no memory of having been informed that p. A proper reliabilist assessment of coverage-supported beliefs must take account not only of the cognitive processes that take place in the coverage relying-subject, but also of the social institutions and practices that are part of the background conditions on the formation of those beliefs. Finally, in Chapter 7, Goldberg emphasizes that, despite his criticisms of Orthodox Reliabilism, the arguments put forth in the previous chapters are in perfect consonance with the tradition of reliabilist epistemology, and that his purpose has been to show that Process Reliabilists should be concerned with social practices and institutions insofar as some of these directly or indirectly affect the reliability of the processes of belief-formation. He also argues that traditional epistemology's focus on the individual subject as the appropriate locus of epistemic assessment is to be explained by the fact that, in doing so, one assesses the individual subject's management of the epistemic reliance on others. The present book can be best described as an original and challenging contribution to a debate among process reliabilists. This does not mean that it will be of interest only to them, since it will engage anyone working in the epistemology of testimony, and social epistemology more generally. It rather means that, given Goldberg's assumptions, many of his arguments will most likely fail to move internalists or those who are skeptical of the viability and legitimacy of the project of social epistemology. Be that as it may, the book is full of clear, ingenious, and persuasive arguments, and I cannot but highly recommend it. Diego E. Machuca Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina)