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Epistemology This comprehensive introduction explains the concepts and theories central to understanding knowledge. The third edition features new sections on such topics as the nature of intuition, the skeptical challenge of rational disagreement, and "the value problem"—the question why knowledge is preferable to mere true belief. Special features of the third edition of Epistemology include: • • • enhanced treatment of key topics such as perception, scientific hypotheses, self-evidence and the a priori, testimony, contextualism, understanding, and virtue epistemology expanded discussion of the relation between epistemology and related fields, especially philosophy of mind, philosophy of science, and ethics greater clarity for undergraduate readers. Praise for the third edition: ". . . Robert Audi's Epistemology, Third Edition, is the most authoritative, comprehensive, and state-of-the-art textbook in the field. In clear, masterful prose, Audi covers all the main topics in epistemology . . . Every student of epistemology—new and old—should read this book." —Peter Graham, University of California, Riverside ". . . unusually comprehensive, elegantly structured, and accessible . . . a cutting-edge treatment of the latest debates about the nature of intuitions, the significance of rational disagreement, and the value of knowledge and justified true belief." —Ralph Kennedy, Wake Forest University ". . . a well-motivated, comprehensive, accessible introduction for students as well as an original, exciting, cutting-edge work of epistemology in its own right. Novices and experts alike will continually profit—and tremendously so—from studying it . . . an ideal text for undergraduate courses in epistemology, and even graduate-level surveys." —E.J. Coffman, University of Tennessee Praise for the second edition: ". . . philosophically insightful and masterfully written—even more so in its new edition. Guaranteed to fascinate the beginner while retaining its exalted status with the experts." —Claudio de Almeida,; PUCRS, Brazil "My students like this book and have learned much from it, as I have . . . Epistemology . . . is simply the best textbook in epistemology that I know of." —Thomas Vinci, Dalhousie University Praise for the first edition: "No less than one would expect from a first-rate epistemologist who is also a master expositor . . . A superb introduction." —Ernest Sosa, Rutgers University "This is a massively impressive book, introducing . . . virtually all the main areas of epistemology. . . . lucid and highly readable, while not shirking the considerable complexities of his subject matter." —Elizabeth .M. Fricker, University of Oxford "A state-of-the-art introduction to epistemology by one of the leading figures in the field." —William P. Alston, Syracuse University Robert Audi is John A. O'Brien Professor of Philosophy at the University of Notre Dame and author of many papers and books on knowledge and belief, justification, and rationality. Epistemology A Contemporary Introduction to the Theory of Knowledge Third Edition Robert Audi Routledge Contemporary Introductions to Philosophy Series editor: Paul K Moser, Loyola University of Chicago This innovative, well-structured series is for students who have already done an introductory course in philosophy. Each book introduces a core general subject in contemporary philosophy and offers students an accessible but substantial transition from introductory to higher-level college work in that subject. The series is accessible to non-specialists and each book clearly motivates and expounds the problems and positions introduced. An orientating chapter briefly introduces its topic and reminds readers of any crucial material they need to have retained from a typical introductory course. Considerable attention is given to explaining the central philosophical problems of a subject and the main competing solutions and arguments for those solutions. The primary aim is to educate students in the main problems, positions, and arguments of contemporary philosophy rather than to convince students of a single position. Epistemology Third edition Robert Audi Philosophy of Language Second edition Willam G. Lycan Philosophy of Mind Third edition John Heil Philosophy of Religion Keith E. Yandell Philosophy of Perception William Fish Metaphysics Third edition Michael J. Loux Philosophy of Mathematics Second edition James Robert Brown Classical Philosophy Christopher Shields Classical Modern Philosophy Jeffrey Tlumak Ethics Harry Gensler Philosophy of Science Second edition Alex Rosenberg Philosophy of Biology Alex Rosenberg and Daniel W. McShea Philosophy of Art Noël Carroll Philosophy of Psychology José Bermudez Social and Political Philosophy John Christman Continental Philosophy Andrew Cutrofello Free Will (forthcoming) Michael McKenna Ethics (forthcoming) Second edition Harry Gensler Feminist Philosophy (forthcoming) Lorraine Code Philosophy of Literature (forthcoming) John Gibson First edition published 1998, second edition published 2003 by Routledge This edition first published 2011 by Routledge 270 Madison Ave, New York, NY 10016 Simultaneously published in the UK by Routledge 2 Park Square, Milton Park, Abingdon, Oxon OX14 4RN Routledge is an imprint of the Taylor & Francis Group, an informa business This edition published in the Taylor & Francis e-Library, 2010. To purchase your own copy of this or any of Taylor & Francis or Routledge's collection of thousands of eBooks please go to www.eBookstore.tandf.co.uk. First edition © 1998 Taylor & Francis Second edition © 2003 Taylor & Francis Third edition © 2011 Taylor & Francis All rights reserved. No part of this book may be reprinted or reproduced or utilized in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging in Publication Data Audi, Robert Epistemology : a contemporary introduction to the theory of knowledge / Robert Audi. — 3rd ed. p. cm. — (Routledge contemporary introductions to philosophy) Includes bibliographical references and index. [etc.] 1. Knowledge, Theory of. I. Title. BD161.A783 2010 121—dc22 2010005139 ISBN 13: 978-0-415-87922-4 (hbk) ISBN 13: 978-0-415-87923-1 (pbk) To Malou Contents Preface to the first edition Acknowledgments to the first edition Preface to the second edition Acknowledgments to the second edition Preface to the third edition Acknowledgments to the third edition Introduction: a sketch of the sources and nature of belief, justification, and knowledge Perception, belief, and justification Justification as process, as status, and as property Knowledge and justification Memory, introspection, and self-consciousness Reason and rational reflection Testimony Basic sources of belief, justification, and knowledge Three kinds of grounds of belief Fallibility and skepticism Overview Part One Sources of justification, knowledge, and truth 1 Perception: sensing, believing, and knowing The elements and basic kinds of perception Seeing and believing Perceptual justification and perceptual knowledge Notes xiii xvi xviii xx xxi xxii 1 1 2 4 5 5 6 6 7 8 9 13 16 17 22 26 31 x Contents 2 3 Theories of perception: sense experience, appearances, and reality Some commonsense views of perception The theory of appearing Sense-datum theories of perception Adverbial theories of perception Adverbial and sense-datum theories of sensory experience Phenomenalism Perception and the senses Notes 38 38 40 41 47 49 51 55 59 Memory: the preservation and reconstruction of the past Memory and the past The causal basis of memory beliefs Theories of memory Remembering, recalling, and imaging Remembering, imaging, and recognition The epistemological centrality of memory Notes 62 63 64 66 72 74 75 79 4 Consciousness: the life of the mind Two basic kinds of mental properties Introspection and inward vision Some theories of introspective consciousness Consciousness and privileged access Introspective consciousness as a source of justification and knowledge Notes 84 84 86 87 91 96 100 5 Reason I: understanding, insight, and intellectual power Self-evident truths of reason The classical view of the truths of reason The empiricist view of the truths of reason Notes 104 104 107 116 121 6 Reason II: meaning, necessity, and provability The conventionalist view of the truths of reason Some difficulties and strengths of the classical view Reason, experience, and a priori justification Notes 130 130 133 138 145 7 Testimony: the social foundation of knowledge The nature of testimony: formal and informal The psychology of testimony 150 150 151 Contents xi The epistemology of testimony The indispensability of testimonial grounds Notes 155 161 167 Part Two The structure and growth of justification and knowledge 8 9 Inference and the extension of knowledge The process, content, and structure of inference Inference and the growth of knowledge Source conditions and transmission conditions for inferential knowledge and justification Memorial preservation of inferential justification and inferential knowledge Notes The architecture of knowledge Inferential chains and the structure of belief The epistemic regress problem The epistemic regress argument Foundationalism and coherentism Holistic coherentism The nature of coherence Coherence and second-order justification Moderate foundationalism Notes 173 176 177 182 185 197 199 206 206 210 215 216 217 221 229 232 236 Part Three The nature and scope of justification and knowledge 243 10 11 The analysis of knowledge: justification, certainty, and reliability Knowledge and justified true belief Knowledge conceived as the right kind of justified true belief Naturalistic accounts of the concept of knowledge Problems for reliability theories Notes 246 246 248 253 257 264 Knowledge, justification, and truth: internalism, externalism, and intellectual virtue Knowledge and justification Internalism and externalism in epistemology Internalist and externalist versions of virtue epistemology 270 270 272 277 xii Contents Justification, knowledge, and truth The value problem Theories of truth Concluding proposals Notes 281 282 286 290 292 12 Scientific, moral, and religious knowledge Scientific knowledge Moral knowledge Religious knowledge Notes 298 298 308 319 328 13 Skepticism I: the quest for certainty The possibility of pervasive error Skepticism generalized The egocentric predicament Fallibility Uncertainty Notes 334 334 337 343 344 347 353 14 Skepticism II: the defense of common sense in the face of fallibility Negative versus positive defenses of common sense Deducibility, evidential transmission, and induction The authority of knowledge and the cogency of its grounds Refutation and rebuttal Prospects for a positive defense of common sense The challenge of rational disagreement Skepticism and common sense Notes 358 358 359 362 365 366 371 374 375 Conclusion 379 Short annotated bibliography of books in epistemology Index 389 399 15 Preface to the first edition This book is a wide-ranging introduction to epistemology, conceived as the theory of knowledge and justification. It presupposes no special background in philosophy and is meant to be fully understandable to any generally educated, careful reader, but for students it is most appropriately studied after completing at least one more general course in philosophy. The main focus is the body of concepts, theories, and problems central in understanding knowledge and justification. Historically, justification— sometimes under such names as 'reason to believe', 'evidence', and 'warrant'—has been as important in epistemology as knowledge itself. This is surely so at present. In many parts of the book, justification and knowledge are discussed separately; but they are also interconnected at many points. The book is not historically organized, but it does discuss selected major positions in the history of philosophy, particularly some of those that have greatly influenced human thought. Moreover, even where major philosophers are not mentioned, I try to take their views into account. One of my primary aims is to facilitate the reading of those philosophers, especially their epistemological writings. It would take a very long book to discuss representative contemporary epistemologists or, in any detail, even a few historically important epistemologies, but a shorter one can provide many of the tools needed to understand them. Providing such tools is one of my main purposes. The use of this book in the study of philosophy is not limited to courses or investigations in epistemology. Epistemological problems and theories are often interconnected with problems and theories in the philosophy of mind; nor are these two fields of philosophy easily separated (a point that may hold, if to a lesser extent, for any two central philosophical fields). There is, then, much discussion of the topics in the philosophy of mind that are crucial for epistemology, for instance the phenomenology of perception, the nature of belief, the role of imagery in memory and introspection, the variety of mental properties figuring in self-knowledge, the nature of inference, and the structure of a person's system of beliefs. Parts of the book might serve as collateral reading not only in pursuing the philosophy of mind but also in the study of a number of philosophers often discussed in philosophy courses, especially Plato, Aristotle, Aquinas, xiv Preface to the first edition Descartes, Leibniz, Locke, Berkeley, Hume, Kant, and Mill. The book might facilitate the study of moral philosophy, such as Kantian and utilitarian ethics, both discussed in some detail in Chapter 9; and it bears directly on topics in the epistemology of religion, some of which are also discussed in Chapter 9. The writing is intended to be as simple and concrete as possible for a philosophically serious introduction that does not seek simplicity at the cost of falsehood. The territory surveyed, however, is extensive and rich. This means that the book cannot be traversed quickly without missing landmarks or failing to get a view of the larger segments and their place in the whole. Any one chapter can perhaps be read at a sitting, but experience has shown that even the shortest chapter covers too many concepts and positions for most readers to assimilate in a single reading and far more than most instructors can cover in any detail in a single session. To aid concentration on the main points, and to keep the book from becoming more complicated, notes are limited, though parenthetical references are given in some places and there is also a short selected bibliography with thumbnail annotations. By and large, the notes are not needed for full comprehension and are intended mainly for professional philosophers and serious students. There are also some subsections that most readers can probably scan, or even skip, without significant loss in comprehending the main points of the relevant chapter. Technical terms are explained briefly when introduced and are avoided when they can be. Most of the major terms central in epistemology are defined or explicated, and boldfaced numbers in the index indicate main definitional passages. But some are indispensable: they are not mere words, but tools; and some of these terms express concepts valuable outside epistemology and even outside philosophy. The index, by its boldfaced page references to definitions, obviates a glossary. It should also be stressed that this book is mainly concerned to introduce the field of epistemology rather than the literature of epistemology—an important but less basic task. It will, however, help non-professional readers prepare for a critical study of that literature, contemporary as well as classical. For that reason, too, some special vocabulary is introduced and a number of the notes refer to contemporary works. The sequence of topics is designed to introduce the field in a natural progression: from the genesis of justification and knowledge (Part One), to their development and structure (Part Two), and thence to questions about what they are and how far they extend (Part Three). Even apart from its place in this ordering, each chapter addresses a major epistemological topic, and any subset of the chapters can be studied in any order provided some appropriate effort is made to supply the (generally few) essential points for which a later chapter depends on an earlier one. For the most part this book does epistemology rather than talk about it or, especially, about its literature. In keeping with that focus, the ordering of chapters is intended to encourage understanding epistemology before Preface to the first edition xv discussing it in large-scale terms, for instance before considering what sort of epistemological theory, say normativist or naturalistic, best accounts for knowledge. My strategy is, in part, to discuss myriad cases of justification and knowledge before approaching analyses of what they are, or the skeptical case against our having them. In one way, this approach differs markedly from that of many epistemological books. I leave the assessment of skepticism for the last chapter; early passages indicate that skeptical problems must be faced and, in some cases, how they are connected with the subject at hand or are otherwise important. Unlike some philosophers, I do not think extensive discussion of skepticism is the best way to motivate the study of epistemology. Granted, historically skepticism has been a major motivating force; but it is not the only one, and epistemological concepts hold independent interest. Moreover, in assessing skepticism I use many concepts and points developed in earlier chapters; to treat it early in the book, I would have to delay assessing it. There is also a certain risk in posing skeptical problems at or near the outset: non-professional readers may tend to be distracted, even in discussing conceptual questions concerning, say, what knowledge is, by a desire to deal with skeptical arguments purporting to show that there is none. There may be no best or wholly neutral way to treat skepticism, but I believe my approach to it can be adapted to varying degrees of skeptical inclination. An instructor who prefers to begin with skepticism can do so by taking care to explain some of the ideas introduced earlier in the book. The first few sections of Chapter 10 (Chapter 13 in the third edition), largely meant to introduce and motivate skepticism, presuppose far less of the earlier chapters than the later, evaluative discussion; and most of the chapter is understandable on the basis of Part One, which is probably easier reading than Part Two. My exposition of problems and positions is meant to be as nearly unbiased as I can make it, and where controversial interpretations are unavoidable I try to present them tentatively. In many places, however, I offer my own view. Given the scope of the book, I cannot provide a highly detailed explanation of each major position discussed, or argue at length for my own views. I make no pretense of treating anything conclusively. But in some cases—as with skepticism—I do not want to leave the reader wondering where I stand, or perhaps doubting that there is any solution to the problem at hand. I thus propose some tentative positions for critical discussion. Acknowledgments to the first edition This book has profited from my reading of many articles and books by contemporary philosophers, and from many discussions I have had with them and, of course, with my students. I cannot mention all of these philosophers, and I am sure that my debt to those I will name—as well as to some I do not, such as some whose journal papers I have read but have not picked up again, and some I have heard at conferences—is incalculable. Over many years, I have benefited greatly from discussions with William Alston, as well as from reading his works; and I thank him for detailed critical comments on parts of the manuscript. Reading of books or articles (or both) by Roderick Chisholm, Richard Foley, Paul Moser, Alvin Plantinga, Walter Sinnott-Armstrong, and Ernest Sosa, and a number of discussions with them, have also substantially helped me over many years. My colleagues at the University of Nebraska, especially Albert Casullo, and several of my students have also helped me at many points. I have learned greatly from the participants in the National Endowment for the Humanities seminars and institutes I have directed. I also benefited much from the papers given to the seminars or institutes by (among others) Laurence BonJour, Fred Dretske, Alvin Goldman, Gilbert Harman, Keith Lehrer, Ruth Marcus, and John Perry, with all of whom I have been fruitfully discussing epistemological topics on one occasion or another for many years. In relation to some of the main problems treated in the book, I have learned immensely from many other philosophers, including Frederick Adams, Robert Almeder, David Armstrong, John A. Barker, Richard Brandt, Panayot Butchvarov, Carol Caraway, the late Hector-Neri Castañeda, Wayne Davis, Michael DePaul, Susan Feagin, Richard Feldman, Roderick Firth, Richard Fumerton, Carl Ginet, Alan Goldman, Risto Hilpinen, Jaegwon Kim, John King-Farlow, Peter Klein, Hilary Kornblith, Christopher Kulp, Jonathan Kvanvig, Brian McLaughlin, George S. Pappas, John Pollock, Lawrence Powers, W.V. Quine, William Rowe, Bruce Russell, Frederick Schmitt, Thomas Senor, Robert Shope, Donna Summerfield, Marshall Swain, William Throop, Raimo Tuomela, James Van Cleve, Thomas Vinci, Jonathan Vogel, and Nicholas Wolterstorff. In most cases I have not only read some Acknowledgments to the first edition xvii epistemological work of theirs, but discussed one or another epistemological problem with them in detail. Other philosophers whose comments or works have helped me with some part of the book include Anthony Brueckner, Stewart Cohen, Earl Conee, Dan Crawford, Jonathan Dancy, Timothy Day, Robert Fogelin, Elizabeth Fricker, Bernard Gert, Heather Gert, David Henderson, Terence Horgan, Dale Jacquette, Eric Kraemer, Noah Lemos, Kevin Possin, Dana Radcliffe, Nicholas Rescher, Stefan Sencerz, James Taylor, Paul Tidman, Mark Timmons, William Tolhurst, Mark Webb, Douglas Weber, Ümit Yalçin, and Patrick Yarnell. I owe special thanks to the philosophers who generously commented in detail on all or most of some version of the manuscript: John Greco, Louis Pojman, and Matthias Steup. Their numerous remarks led to many improvements. Detailed helpful comments were also provided by readers for the Press, including Nicholas Everett, Frank Jackson, and Noah Lemos. All of the philosophers who commented on an earlier draft not only helped me eliminate errors, but also gave me constructive suggestions and critical remarks that evoked both clarification and other improvements. I am also grateful for permission to reuse much material that appears here in revised form from my Belief, Justification, and Knowledge (Wadsworth Publishing Co., 1988) and I thank the editor of American Philosophical Quarterly for allowing me to use material from 'The Place of Testimony in the Fabric of Knowledge and Justification' (vol. 34, 1997). For advice and help at several stages I thank Paul Moser, Editor of the series in which this book appears, and Adrian Driscoll and the staff at Routledge in London, including Moira Taylor and Sarah Hall, and Dennis Hodgson. Robert Audi February, 1997 Preface to the second edition This preface will presuppose the Preface to the first edition and can therefore be brief. Many improvements have been made in this edition, but they do not make the previous preface inapplicable, and reading it should help anyone considering a study of even part of the book. My main concern in revising has been to produce a book that is both philosophically stronger and easier to read. Doing this has required adding new substantive material, making minor changes throughout, adding or extending many examples, making various refinements and corrections, and bringing in new references, notes, and bibliography. Instructors who have used the volume in their teaching will find that the content and organization are highly similar and that a transition from the first edition to this one is easy. Students and people reading for general interest should find the book easier to understand. The emphasis is still on enhancing comprehension of the field of epistemology—its concepts, problems, and methods—rather than on presenting its literature. But, perhaps even more than in the first edition, the book is generally in close contact with both classical and contemporary literature. In this edition there are also many more references to pertinent books and papers, particularly those published in recent years. This edition includes more extensive discussion of virtue epistemology and social epistemology, with feminist epistemology figuring significantly (though not exclusively) in relation to social epistemology. The connection of epistemology with philosophy of mind and language also receives more emphasis in this edition. So does contextualism and the related theory of "relevant alternatives." I am happy to say that Routledge has published a fine and wide-ranging new collection of readings to accompany this book: Michael Huemer's Epistemology: Contemporary Readings (2002). Huemer has chosen classical and contemporary book sections and papers that go well with every chapter in the present book; his larger sections match mine; and he offers helpful introductions to each section and study questions on each chapter. Preface to the second edition xix This edition of my book is certainly self-contained, but its integration with Huemer's supporting collection (for which I have done a long narrative introduction to help both instructors and students) is close, and the two together provide enough substance and diversity to facilitate numerous different kinds of epistemology courses. Acknowledgments to the second edition Fortunately, I have continued to benefit from reading of or discussions with most of the people acknowledged above, in the first edition. But since that writing I have come to know the work of many other writers in the field and profited from teaching many more students. I am bound to omit some people I should thank, but I want to acknowledge here a number of people not mentioned above: John Broome, Tyler Burge, David Chalmers, Roger Crisp, Mario DeCaro, Keith DeRose, Rosaria Egidi, Guido Frongia, Douglas Geivett, Joshua Gert, Peter Graham, D.W. Hamlyn, Brad Hooker, Christopher Hookway, Michael Huemer, Jonathan Jacobs, Ralph Kennedy, Simo Knuutila, Matthias Lutz-Bachmann, Hugh McCann, John McDowell, Tito Megri, Cyrille Michon, Nicholas Nathan, Ilkka Niiniluoto, Tom O' Neil, Derek Parfit, James Pryor, Jlenia Quartarone, Joseph Raz, John Searle, John Skorupski, David Sosa, William Talbot, Wilhelm Vossenkuhl, Fritz Warfield and Paul Weirich. In addition, I have continued to benefit from regular exchanges of ideas or papers (usually both) with many philosophers, including William Alston, Laurence BonJour, Panayot Butchvarov, Elizabeth Fricker, Alvin Goldman, John Greco, Gilbert Harman, Jaegwon Kim, Christopher Kulp, Jonathan Kvanvig, Bruce Russell, Walter Sinnott-Armstrong, Ernest Sosa, Matthias Steup, Eleonore Stump, Richard Swinburne, Raimo Tuomela, Nicholas Wolterstorff, and Linda Zagzebski. Readers of earlier versions of this edition deserve special thanks, not only the anonymous readers for the Press but also Michael Pace, Bruce Russell, Mark Owen Webb, and especially Claudio de Almeida, who provided numerous expert comments and criticism (more, indeed, than I could fully take into account in the available time and space). Special thanks are also due the Editors at Routledge, particularly Tony Bruce, Simon Bailey, and Siobhan Pattinson, whose ideas and support have been immensely helpful. Preface to the third edition This edition reflects some of the benefits of nearly a decade of teaching and writing about epistemology since the second edition went to press. There are revisions and improvements throughout. Some revisions are responsive to new developments in epistemological literature; others respond to comments by professional colleagues, including various instructors who have used the book. Student responses have also been taken into account. The book is structurally much as in the second edition, and the previous prefaces largely apply to it. As before, instructors should read prefatory material and the introduction. Long chapters have been divided, but the chapters remain cumulative in content. Most of them, however, can be read independently of the others or by simply looking into some earlier chapter at certain points. The index may also help readers, and its boldface numerals indicate places where the term in question is defined. Those who have used the second edition will find no difficulty adjusting their teaching or discussions to this one. Chapters that have been divided still cover the same issues, though with new material included and revisions of much that is included. The fit with Michael Huemer's large collection of major papers (cited in the bibliography) is equally good. Some topics treated in this edition are not addressed in the second. These include the nature of intuitions, the skeptical challenge of rational disagreement, and the value problem: the range of questions concerning why knowledge and justified true belief have value beyond that of merely true belief. Other topics receive considerably more exploration than in the second edition, especially contextualism, perception (including perceptual content), self-evidence and the a priori, memorial justification, inferential versus direct knowledge, inference to the best explanation, scientific hypotheses, testimony and trust, understanding, and virtue epistemology. Acknowledgments to the third edition I have been fortunate in being able to exchange ideas with most of the philosophers named in the previous two sets of acknowledgments, and this book has continued to benefit from those discussions. I look back on them with much gratitude. I should particularly mention continuing conversations with the late William P. Alston and with Laurence BonJour, Mario DeCaro, Elizabeth Fricker, Peter Graham, John Greco, Ralph Kennedy, Peter Klein, Christopher Kulp, Jonathan Kvanvig, Jennifer Lackey, Bruce Russell, Walter Sinnott-Armstrong, Ernest Sosa, and Thomas Vinci. On one or another topic in the book I have greatly benefited from epistemological discussions with my Notre Dame colleagues Marian David, Michael DePaul, Peter van Inwagen, Alvin Plantinga, Leopold Stubenberg, and Fritz Warfield. Interactions with Andrew Bailey, Michael Bergmann, E.J. Coffman, Roger Crisp, Claudio De Almeida, Keith DeRose, Fred Dretske, Richard Feldman, Richard Fumerton, Alvin Goldman, Christopher Green, Stephen Grimm, Michael Huemer, Thomas Kelly, Matthew Kennedy, Hilary Kornblith, Markus Lamenranta, Duncan Pritchard, Baron Reed, David Sosa, Jeff Speaks, Matthias Steup, Raimo Tuomela, Jonathan Vogel, Michael Zimmerman, and, especially, Sanford Goldberg and Timothy Williamson have also been of great help to me. Detailed comments on the penultimate version were provided by Scott Hagaman and (on a few parts) by Matthew Lee and Ezra Cook, and these were of great help. Hagaman also made numerous helpful comments and critical remarks in seminar discussions at Notre Dame. The numerous questions and responses by seminar students at the Universities of Notre Dame and Nebraska have been valuable at many points. The editorial advice of Andrew Beck, Andrew R. Davidson, Michael Andrews, and, since the book's first edition, Tony Bruce have helped me in several important matters. They and their staff have been essential in both design and production. Introduction A sketch of the sources and nature of belief, justification, and knowledge Before me is a grassy green field. A line of trees marks its far edge, which is punctuated by a spruce on its left side and a maple on its right. Birds are singing. A warm breeze brings the smell of roses from a nearby trellis. I reach for a glass of iced tea, still cold to the touch and flavored by fresh mint. I am alert, the air is clear, the scene is quiet. My perceptions are quite distinct. It is altogether natural to think that from perceptions like these, we come to know a great deal—enough to guide us through much of daily life. But we sometimes make mistakes about what we perceive, just as we sometimes misremember what we have done, or infer false conclusions from what we believe. We may then think we know something when in fact we do not, as when we make errors through inattention or are deceived by vivid dreams. And is it not possible that we are mistaken more often than we think? Perception, belief, and justification Philosophers have thought a great deal about these matters, especially about the nature of perceiving and about what we can know—or may mistakenly think we know—through perception or through other sources of knowledge, such as memory as a storehouse of what we have learned in the past, consciousness as revealing our inner lives, reflection as a way to acquire knowledge of abstract matters, and testimony as providing knowledge originally acquired by others. In approaching these topics in epistemology—the theory of knowledge and justification—it is appropriate to begin with perception. In my opening description, what I detailed was what I perceived: what I saw, heard, smelled, felt, and tasted. In describing my experience, I also expressed some of what I believed: that there was a green field before me, that there were bird songs, that there was a smell of roses, that my glass felt cold, and that the tea tasted of mint. It seems altogether natural to believe these things given my experience, and I think I justifiedly believed them. I believed them, not in the way I would if I accepted the result of wishful thinking or of merely guessing, but with justification. By that I mean above all that the beliefs I refer to were justified. 2 Introduction This a good thing; justified beliefs are of a kind it is desirable and reasonable to hold. Justification as process, as status, and as property Being justified, in the sense illustrated by my beliefs about what is clearly before me, need not be the result of a process. Being justified is not, for instance, like being purified, which requires a process of purification. My beliefs about what is before me are not justified because they have been through a process of being justified, as when we defend a controversial belief by giving reasons for it. They have not; the question whether they are justified has not even come up. No one has challenged them or even asked why I hold them. They are justified—in the sense that they have the property of being justified—justifiedness—because there is something about them in virtue of which they are natural and appropriate for me as a normal rational person. We can see what justifiedness is by starting with a contrast. Unlike believing something that one might arrive at through a wild guess in charades, our justified perceptual beliefs are justified for us simply through their arising in the normal way from our clear perceptions. Roughly, they are justified in the sense that they are quite in order from the point of view of the standards for what we may reasonably believe. That, in turn, is roughly what we may believe without being subject to certain kinds of criticism, say as intellectually lax, as sloppy, as overhasty, or the like. Justified beliefs are also a kind that we tend to expect to be true. Imagine someone's saying 'His belief is justified, but I don't expect it to turn out to be true'. Without special explanation, this would be to take away with one hand something given by the other. In saying that I justifiedly believe there is a green field before me, I am implying something else, something quite different, though it sounds very similar, namely that I am justified in believing there is a green field before me. To see the difference, notice that we can be justified in believing something—roughly in the sense that we have a justification for believing it— without believing it at all, quite as we can be justified in doing something, such as criticizing a person who has failed us, without doing it. Similarly, I might be justified in believing that I can do a certain difficult task, yet fail to believe this until someone helps me overcome my hesitation. I may then see that I should have believed it. Being justified in believing something is having justification for believing it. This, in turn, is roughly a matter of having ground for believing it (and we also speak of having a ground or a justification or a reason). Just as we can have reason to do things we do not do, we can have reason to believe things we do not believe. You can have reason to go to the library and forget to, and I can have reason to believe someone is making excuses for me but—because I have no inkling that I need any—fail to believe this. Our justification for believing is basic raw material for actual justified belief; and justified belief is commonly good raw material for knowledge. Introduction 3 The two justificational notions are intimately related: if one justifiedly believes something, one is also justified in believing it, hence has justification for believing it. But the converse does not hold: not everything we are justified in believing is something we do believe. When I look at a lawn, I am justified in believing it has more than ten blades of grass per square foot, but I would not normally have any belief about the number of blades per square foot. We have more justificational raw material than we need or use. We do not believe anywhere near the number of things that we have justification to believe. This holds not just in trivial matters but also in, for instance, mathematics. There are many things we are justified in believing which we do not actually believe, such as the proposition that normal people do not drink 100 liters of water a day. Let us call the first kind of justification—justifiedly believing—belief justification, as it belongs to actual beliefs. It is also called doxastic justification, from the Greek doxa, translatable as 'belief'. Call the second kind—being justified in believing—situational justification, since it is based on the informational situation one is in. It is a status one has in virtue of that situation. This situation includes not just what one perceives, but also one's background beliefs and knowledge, such as the belief that people drink at most a few liters of water a day. Situational justification is also called propositional justification, since the proposition in question is justified for the person whose situation provides justification for believing it, and the person has justification for it. In any ordinary situation in waking life, we have both a lot of general information stored in memory and much specific information presented in our perceptions. We do not need all this information, and our situational justification for believing something is often unaccompanied by our actually believing that it is so. We have situational justification for vastly more justified beliefs than we actually have. Here nature is very generous. We are built to gain from a mere glance enough information to ground vastly more beliefs than we normally form or rely on. Without situational justification, such as the kind that comes from seeing a green field, there would be no belief justification. I would not, for instance, justifiedly believe that there is a green field before me. We cannot have a justified belief without being in a position to have it. Without situational justification, we are not in such a position. Without belief justification, on the other hand (i.e., doxastic justification), we would have no beliefs of a kind we want and need, those with a positive status—being justified—that makes them appropriate for us as rational creatures and warrants us in expecting them to be true. Belief justification, then, is more than the situational kind it presupposes. Belief justification occurs when there is a certain kind of connection between what yields situational justification and the justified belief that benefits from it. Belief justification occurs when a belief is grounded in, and thus in a way supported by (or based on), something that gives one situational 4 Introduction justification for that belief, such as seeing a field of green. Seeing is of course perceiving; and perceiving is a basic source of knowledge—perhaps our most elemental source, at least in childhood. This is largely why perception is so large a topic in epistemology. Knowledge and justification Knowledge would not be possible without belief justification—or a kind of grounding significantly like it. If I did not have the kind of justified belief I do—if, for instance, I were wearing dark sunglasses and could not tell the difference between a green field and a smoothly ploughed one that is really an earthen brown—then on the basis of what I now see I would not know that there is a green field before me. To see how knowledge fits into the picture so far sketched, consider two points. First, justified belief is important for knowledge because at least the typical things we know we also justifiedly believe on the same basis that grounds our knowing them. If I know someone is making excuses for me, say by the way she explains my lateness, I do not just believe this but justifiedly believe it. Second, much of what we justifiedly believe we also know. Surely I could have maintained, regarding each of the things I have said I justifiedly believed through perception, that I also knew it. And do I not know these things—say that there is a lawn before me and a car on the road beyond it—on the same basis on which I justifiedly believe them, for instance on the basis of what I see and hear? This is very plausible. As closely associated as knowledge and justified belief are, there is a major difference. If I know that something is so, then it is true, whereas I can justifiedly believe something false. If a normally reliable friend tricked me into believing something false, say that he lost my car keys, I could still justifiedly believe he lost them. We must not assume, then, that everything we learn about justified belief applies to knowledge. We should look at both concepts independently. I said that I saw the green field and that my belief that there was a green field before me arose from my seeing it. If the belief arose, under normal conditions, from my seeing the field (so that I believed it is there simply because I saw it there), then the belief was true, justified, and constituted knowledge. Again, however, we can alter the example to bring out how knowledge and justification may diverge: the belief might remain justified even if, unbeknownst to me, the grass had been burned up since I last saw it, and there was now a perfect artificial replica of it spread out in grassy-looking strips of cloth that hide the charred ground. Then, although I might think I know the green field is there, I would only falsely believe I know this. Such a bizarre happening is, to be sure, improbable. Still, a justified but false belief could arise in this way. Introduction 5 Memory, introspection, and self-consciousness As I look at the field before me, I remember carefully cutting a poison ivy vine from the trunk of the spruce. Surely, my memory belief that I cut off this vine is justified. I think I also know that I did this. But here I confess to being less confident than I am of the justification of my perceptual belief, held in the radiant sunlight, that there is (now) a green field before me. As our memories become less vivid, we tend to be correspondingly less sure that our beliefs apparently based on them are justified. Still, I distinctly recall cutting the vine. The stem was furry; it was bonded to the tree trunk; the cutting was difficult and slightly wounded the tree. By contrast, I have no belief about whether I did this in the summer or the fall. I entertain the proposition that it was in the summer; I consider whether it is true; but, being utterly uncertain, I suspend judgment on it. I thus neither believe it nor disbelieve it, that is, believe it is false. My stance is one of non-belief. I need not try to force myself to resolve the question and judge the proposition either way. I might need to resolve it if something important turned on when I did the pruning; but here suspended judgment, with the resulting non-belief, is not uncomfortable. As I think about cutting the vine, it occurs to me that in recalling that task, I am vividly imaging it. Here, I seem to be looking into my own consciousness, thus engaging in a kind of introspection. I can still see, in my mind's eye, the furry vine clinging to the tree, the ax, the sappy wound along the trunk where the vine was severed from it. I have turned my attention inward to my own imagery. The object of my attention, my own imaging of the scene, seems internal and is present to my consciousness, though its object is external and long gone by. But clearly, I believe that I am imaging the vine; and there is no apparent reason to doubt that I justifiedly believe this and know that it is so. This is a simple case of self-knowledge. Reason and rational reflection I now look back at the field and am struck by how perfectly rectangular it looks. If it is perfectly rectangular, then its corners are right angles. Here I believe something different in kind from the things cited so far: that if the field is rectangular, then its corners are right angles. This is a geometrical belief. I do not hold it on the same sort of basis I have for the other things I have mentioned believing. My conception of geometry as applied to ideal figures seems to be my basis. On that basis, my belief seems to be firmly justified and to constitute knowledge. I can see that the spruce is taller than the maple, and that the maple is taller than the crab apple tree on the lawn closer by. I now realize that the spruce is taller than the crab apple. My underlying belief here is that if one thing is taller than a second and the second taller than a third, then the first is taller than the third. And, perhaps even more than the geometrical belief, 6 Introduction this abstract belief seems to arise simply from my grasp of the concepts in question, above all the concept of one thing's being taller than another. Testimony The season has been dry, and it now occurs to me that the roses will not flourish without a good deal of water. But this I do not believe simply on the basis of perception. One source from which I learned it is repeated observation. But there is another possible source: although much knowledge comes directly from our own experience, much also originates with testimony from others. I have received testimony as to where on the stem to trim off dead roses. If I did not learn about watering roses from my own experience, I could have learned the same things from testimony, just as I learned from a friend how far back to clip off dead roses. To be sure, I need perception, such as hearing what I am told, to acquire knowledge on the basis of testimony, just as I needed perception to learn these things about roses on my own; and I need memory to retain them whatever their source. They are, however, generalizations and hence do not arise from perception in the direct and apparently simple way my visual beliefs do, or emerge from memory in the way my beliefs about past events I witnessed do. But do I not still justifiedly believe that the roses will not flourish without a lot of water? The commonsense view is that I both justifiedly believe and know this about roses, and that I can know it either through generalizing—a kind of reasoning—from my own observations, or from testimony, or from both. Basic sources of belief, justification, and knowledge The examples just given represent what philosophers have called perceptual, memorial, introspective, a priori, inductive, and testimony-based beliefs. The first four kinds are basic in epistemology. My belief that the glass is cold to the touch is perceptual, being based as it is on tactual perception. My belief that I cut the poison ivy vine from the spruce is memorial, since it is stored in my memory and held because of that fact. My belief that I am imagining a green field is called introspective because it is conceived as based on "looking within" (the etymological meaning of 'introspection'); but it could also be called simply self-directed: no "peering" within or special concentration is required. My belief that if the spruce is taller than the maple and the maple is taller than the crab apple then the spruce is taller than the crab apple is called a priori (meaning, roughly, based on what is "prior" to observational experience) because it apparently arises not from experience of how things actually behave, but simply in an intuitive way. It arises from a rational grasp of the key concepts one needs in order to have the belief, such as the concept of one thing's being taller than another. By contrast, my belief that the roses will not grow well without abundant Introduction 7 water does not arise directly from one of the four basic sources just mentioned: perception, memory, introspection, and a priori intuition (reason, in one sense of the term). It is called inductive because it is formed (and held) on the basis of a generalization from something more basic, in this case what I learned from perceptual experiences with roses. Those experiences, apparently through my beliefs recording them, "lead into" the generalization about roses, to follow the etymological meaning of 'induction'. For instance, I remember numerous cases in which roses have faded when dry, and I eventually concluded that they need abundant water. Each of the four basic kinds of belief I have described—perceptual, memorial, introspective, and a priori—is grounded in the source from which it arises. The nature of this grounding is explored in detail in Part One, which concerns perception, memory, consciousness, and reason. These sources are commonly taken to provide raw materials for inductive generalizations, as where observations and memories about roses yield a basis for generalizing about their needs. Any of the beliefs we considered could instead have been grounded in testimony (the topic of Chapter 7), had I formed the beliefs on the basis of being given the same information by someone I trust. That person, however, would presumably have acquired it through one of these other sources (or ultimately through someone's having done so), and this makes testimony a different kind of source. This is why testimony is not a basic source of knowledge. It is still, however, incalculably important for human knowledge and unlimitedly broad. It can, for instance, justify a much wider range of propositions than perception can. We can credibly tell others virtually anything we know. Three kinds of grounds of belief Our examples illustrate not only grounding of beliefs in a source, such as perception or introspection, but also how they are grounded in these sources. There are at least three important kinds of grounding of beliefs—ways they are grounded. These are causal, justificational, and epistemic grounding. All three are important for many major epistemological questions. Consider my belief that there is a green field before me. It is causally grounded in my experience of seeing the field because that experience produces or underlies the belief. It is justificationally grounded in that experience because the experience, or at least some element in the experience, justifies my belief. And it is epistemically grounded in the experience because in virtue of that experience my belief constitutes knowledge that there is a green field before me ('epistemic' comes from the Greek episteme meaning, roughly, 'knowledge'). These three kinds of grounding very often coincide (though Chapter 11 will describe important cases in which knowledge and justification do not). I will thus often speak simply of a belief as grounded in a source, such as visual experience, when what grounds the belief does so in all three ways. 8 Introduction Causal, justificational, and epistemic grounding each go with a very common kind of question about belief. Let me illustrate. Causal grounding goes with 'Why do you believe that?' An answer to this, asked about my belief that there is a green field before me, would be that I see it. This is the normal kind of reply; but as far as mere causal production of beliefs goes, the answer could be brain manipulation or mere hypnotic suggestion. If, however, mere brain manipulation or mere hypnotic suggestion produces a belief, then the causal ground of the belief would not justify it. If, under hypnosis, I am told that someone dislikes me and as a result I believe this, the belief is not thereby justified. Justificational grounding goes with such questions as 'What is your justification for believing that?' or 'What justifies you in thinking that?' or 'Why should I accept that?' ('Why do you believe that?' can be asked with this same justification-seeking force.) Again, I might answer that I see it. I might, however, have a justification (the situational kind) that, unlike seeing the truth in question, is not a cause of my believing it. The justification I cite could also be the testimony of a credible good friend. It could be this even when, by a short circuit, brain manipulation does the causal work of producing my belief and leaves the testimony like a board that slides just beneath a roof beam but bears none of its weight. This shows that an element that provides situational justification for a belief may play no role in producing or supporting the belief, even if this element, like the auxiliary unstressed board, stands ready to play a supporting role if the belief is put under pressure by a challenge. Epistemic grounding goes with 'How do you know that?' Once again, saying that I see it will commonly answer this. Here, however, it may be that a correct answer must cite something that is also a causal ground for the belief (a matter discussed in Chapter 10). Certainly a justificational ground need not be a ground of knowledge. One can justifiedly believe a proposition without knowing it. Clearly, the same sorts of points can be made for the other five cases I have described: memorial beliefs are grounded in memory, self-directed ("introspective") beliefs in consciousness, inductively based beliefs in further, premise-beliefs that rest on experience, a priori beliefs in reason, and testimony-based beliefs in testimony. Fallibility and skepticism Even well-grounded beliefs can be mistaken. We can be deceived by our senses. We are fallible in perceptual matters, as in our memories, in our reasoning, and in other respects. One might now wonder, as skeptics do, whether we know even that it is improbable that our senses are now deceiving us. One might also wonder whether, when we take ourselves to see green grass, we are even justified in our belief that no such mistake has occurred. Suppose that I am in an unfamiliar park. I might not know or even Introduction 9 justifiedly believe that artificial grass has not replaced the natural grass I take to be before me. (I may have heard of such substitutions and may have no good reason to believe this has not happened, though I do not consider the matter.) Am I justified in believing that there is green grass before me? Suppose that I am not justified in believing there is green grass before me. If not, how can I be justified in believing what appear to be far less obvious truths, such as that my home is secure against the elements, my car safe to drive, and my food free of poison? And how can I know the many things I need to know in life, such as that my family and friends are trustworthy, that I can control my behavior and thus partly determine my future, and that the world we live in at least approximates the structured reality portrayed by common sense and science? These are difficult and important questions. They indicate how insecure and disordered human life would be if we could not suppose that we possess justified beliefs and knowledge. We stake our lives every day on what we take ourselves to know. It would be unsettling to revise this stance and retreat to the view that at best we have justification to believe. But if we had to give up even this moderate view and to conclude, say, that what we believe is not even justified, we would face a crisis. Much later, in discussing skepticism, I will explore such questions at some length. Until then I will assume the commonsense view that beliefs with a basis like that of my belief that there is a green field before me are not only justified but also constitute knowledge. Once we proceed on this commonsense assumption, it is easy to see that there are many different kinds of circumstances in which beliefs arise in such a way that they are apparently both justified and constitute knowledge. In considering this variety of circumstances yielding justification and knowledge, we can explore how beliefs are related to perception, memory, consciousness, reason, and testimony (the topics of Chapters 1–7). Overview There is a great deal more to be said about each of these sources of belief, justification, and knowledge and about how they ground what they do ground. The first seven chapters explore, and in some cases compare, the basic sources of belief, justification, and knowledge. In the light of what those chapters show, we can discuss the development and structure of knowledge and justification (the task of Part Two). Much of what we believe does not come directly from perception, memory, introspection, or reflection of the kind appropriate to knowledge of such truths as those of elementary mathematics or those turning on our grasp of simple relations, for instance the proposition that if the spruce is taller than the maple, then the maple is shorter than the spruce, which we know by virtue of understanding the relations expressed by 'taller' and 'shorter'. We must explore how inference and other developmental processes expand our body of knowledge and justified beliefs (this is the task of Chapter 8). Moreover, 10 Introduction once we think of a person as having the resulting complex body of knowledge and justified belief, we encounter the questions of what structure that large and intricate body has, and of how its structure is related to the amount and kind of knowledge and justification it contains. As we shall see in Part Two, these structural questions take us into an area where epistemology and the philosophy of mind often overlap. On the basis of what Part One shows about sources of knowledge and justification and what Part Two shows about their development and structure, we can fruitfully proceed to consider more explicitly what knowledge and justification are and what kinds of things can be known (the task of Part Three). It is true that if we had no sense at all of what they are, we could not find the kinds of examples of them needed to explore their sources and their development and structure. If we do not have before us a wide range of examples of justification and knowledge, we lack the data appropriate to seeking a philosophically illuminating analysis of them. It is in the light of the examples and conclusions of Parts One and Two that Chapters 10 and 11 clarify the concept of knowledge, and, to a lesser extent, that of justification, in some detail. With a conception of knowledge laid out, it is possible to explore the apparent extent of knowledge and justification in three major territories—the scientific, the ethical, and the religious. In exploring these domains, Chapter 12 applies some of the epistemological results of the earlier chapters. These chapters continue to assume the commonsense view that we have a great deal of knowledge and justification. If, however, skepticism is justified, then the commonsense assessment that the first twelve chapters make regarding the extent of knowledge and justification must be revised. Whether skepticism is justified is the focus of Chapters 13 and 14. Along the way in all fourteen chapters, there is much to be learned about concepts that are important both in and outside epistemology, especially those of belief, causation, certainty, coherence, explanation, fallibility, illusion, inference, intellectual virtue, introspection, intuition, meaning, memory, rationality, reasoning, relativity, reliability, truth, and understanding. There are also numerous epistemological positions to be considered, sometimes in connection with historically influential philosophers. But the main focus will be on the major concepts and problems in the field, not on any particular philosopher or text. This may well be the best way to facilitate studying philosophers and epistemological texts; it will certainly simplify an already complex task. Knowledge and justification are not only interesting in their own right as central epistemological topics; they also represent positive values in the life of every reasonable person. For all of us, there is much we want to know. We also care whether we are justified in what we believe—and whether others are justified in what they tell us. The study of epistemology can help in making this quest, even if it often does so indirectly. It can certainly help us assess how well we have done in the quest when we review our results. Introduction 11 Well-developed concepts of knowledge and justification can serve as ideals in human life. Positively, we can try to achieve knowledge and justification in relation to subjects that concern us. Negatively, we can refrain from forming beliefs where we think we lack justification, and we can avoid claiming knowledge where we think we can at best hypothesize. If we learn enough about knowledge and justification conceived philosophically, we can better search for them in matters that concern us and can better avoid the dangerous pitfalls that come from confusing mere impressions with justification or mere opinion with knowledge. This is not to say that epistemological knowledge can be guaranteed to yield new everyday knowledge. But the more we know about the constitution of knowledge and justification, the better we can build them through our own inquiries, and the less easily we will fall into the pervasive temptation to take an imitation to be the real thing. Part One Sources of justification, knowledge, and truth 1 Perception Sensing, believing, and knowing • The elements and basic kinds of perception Perceptual belief Perception, conception, and belief Propositional and objectual perception • Seeing and believing Perceptually embedded beliefs Perception as a source of potential beliefs The perceptual hierarchy Simple, objectual, and propositional perception The informational character of perception • Perceptual justification and perceptual knowledge Seeing and seeing as Perceptual content Seeing as and perceptual grounds of justification Seeing as a ground of perceptual knowledge 1 Perception Sensing, believing, and knowing As I look at the green field before me, I might believe not only that there is a green field there but also that I see one. And I do see one. I visually perceive it. Both beliefs, the belief that there is a green field there, and the self-referential belief that I see one, are grounded, causally, justificationally, and epistemically, in my perceptual experience. They are produced by that experience, justified by it, and constitute knowledge in virtue of it. The same sort of thing holds for the other senses. Consider touch. I not only believe, through touch (as well as sight), that there is a glass here, I also feel its cold surface. Both beliefs—that there is a glass here and that it is cold—are grounded in my tactual experience. I could believe these things on the basis of someone's testimony. My beliefs would then have a quite different status. For instance, my belief that there is a glass here would not be a perceptual belief, but only a belief about a perceptible, that is, a perceivable object, the kind of thing that can be seen, touched, heard, smelled, or tasted. Through testimony we have beliefs about perceptibles we have never seen or experienced in any way. My concern is not with the hodgepodge of beliefs that are simply about perceptibles, but with perception and perceptual beliefs. Perceptual beliefs are not simply beliefs about perceptibles; they are beliefs grounded in perception. We classify beliefs as perceptual by the nature of their roots, not by the color of their foliage; by their grounds, not their type of content. Those roots may be visual, auditory, and so forth for each perceptual mode. But vision and visual beliefs are an excellent basis for discussing perception, and I will concentrate on them and mention the other senses only when it adds clarity. Perception is a source of knowledge and justification mainly by virtue of yielding beliefs that constitute knowledge or are justified. But we cannot hope to understand perceptual knowledge and justification simply by exploring those beliefs. We must also understand what perception is and how it yields beliefs. We can then begin to understand how it yields knowledge and justification or—sometimes—fails to yield them. Perception 17 The elements and basic kinds of perception There are apparently at least four elements in perception: (1) the perceiver, me; (2) the object, the field I see; (3) the sensory experience, say my visual experience of colors and shapes; and (4) the relation between the object and the subject, commonly taken to be a causal relation by which the object produces the sensory experience in the perceiver. To see the field is apparently to have a certain sensory experience as a result of the impact of the field on our vision. Some accounts of perception add to the four items on this list; others subtract from it. To understand perception we must consider both kinds of account and how these elements are to be conceived in relation to one another. But first, it is essential to explore examples of perception. There are several quite different ways to speak of perception. Each corresponds to a different way of perceptually responding to experience. We often speak simply of what people perceive, for instance see. We also speak of what they perceive the object to be, and we commonly talk of facts they know through perception, such as that the grass is long. Visual perception most readily illustrates this, so let us start there. I see, hence perceive, the green field. Second, speaking in a less familiar way, I see it to be rectangular. Thus, I might say that I know it looks irregular from the nearby hill, but from the air you can see it to be perfectly rectangular. Third, I see that it is rectangular. Perception is common to all three cases. Seeing, which is a paradigm perception, is central in each. The first case is one of simple perception, perception taken by itself (here, visual perception). I see the field, and this experience is the visual parallel of hearing a bird (an auditory experience), touching a glass (a tactual experience), smelling roses (an olfactory experience), and tasting mint (a gustatory experience). If the first case is simply perceiving of some object, the second is a case of perceiving to be, as it is seeing something to be so: I do not just see the field, as when I drive by at high speed and do not even realize what is in my peripheral vision; rather, I see the field to be rectangular. The third case is one of perceiving that; it is seeing that a particular thing is so, namely that the field is rectangular. These cases represent three kinds, or modes, of perception. Perception of the simplest kind (or in the simplest mode), such as seeing, occurs in all three; but, especially because of their relation to knowledge and justified belief, they are significantly different. We can best understand these three kinds (or modes) of perception if we first focus on their relation to belief. Perceptual belief The last two cases—perceiving that, and perceiving to be—are different from the first—perceiving of—in implying corresponding kinds of beliefs: seeing that the field is rectangular implies believing that it is, and seeing it 18 Sources of justification, knowledge, and truth to be green implies believing it to be green. If we consider how both kinds of beliefs—beliefs that something is so and beliefs of (hence about) something—are related to perception, we can begin to understand how perception occurs in all three cases, the simple and the more complex. In my second and third examples of perception, visual perception (seeing) issues in beliefs that are grounded in seeing and can thereby constitute visual knowledge, such as knowing that the field is green.1 In our example of simple perception, my just seeing the field provides a basis for both kinds of beliefs. It does this even if, because my mind is entirely occupied with what I am hearing on the radio as I glance over the field, no belief about the field actually arises in me. The visual experience is, in this instance, like a foundation that has nothing built on it but is ready to support a structure. If, for example, someone were to ask if the field has shrubbery, then given the lilacs prominent in one place, I might immediately form the belief that it does and assent. This belief is visually grounded; it comes from my seeing the field though it did not initially come with it. When visual experiences do produce beliefs, as they usually do, what kinds of beliefs are these, and how are they specifically perceptual? Many of my beliefs arising through perception correspond to perception that, say to seeing that the lilacs are blooming. I believe that the field is lighter green toward its borders, that it is rectangular in shape, and that it has many ruts. But I may also have various beliefs about it that are of the second kind: they correspond to perception to be, for instance to seeing something to be a certain color. Thus, I believe the field to be green, to be rectangular, and so on. The difference between these two kinds of belief is significant. As we shall shortly see, it corresponds first of all to two distinct ways in which we are related to the objects we perceive and, second, to two different ways of assessing the truth of what, on the basis of our perceptions, we believe. The first kind of belief just described is the kind people usually think of when they consider beliefs: it is called propositional, as it is generally considered a case of believing a proposition—say, that the field is rectangular. The belief is thus true or false depending on whether the proposition in question—here that the field is rectangular—is true or false. In holding the belief, moreover, in some way I think of what I see as a field which is rectangular: in believing that the field is rectangular, I conceive what I take to be rectangular as a field. The second kind of belief might be called objectual: it is a belief regarding an object, say the field, with which the belief is actually connected. This is an object of (or about) which I believe something, say that it is rectangular. If I believe the field to be rectangular, there really is such an object, and I have a certain relation to it. A special feature of this relation is that there is no particular proposition I must believe about the field. To see that there is no particular proposition, notice that in holding this objectual belief I need not think of what I see as a field. I might mistakenly take it to be (for instance) a lawn or a grasslike artificial turf, yet still believe it to be rectangular. I might Perception 19 think of it just in terms of what I believe it to be and not in terms of anything else. Thus, although there is some property I must take the field to have—corresponding to what I believe it to be—there is no other particular way I must think of it. With objectual belief, then, there is no particular notion, no specific conceptual "handle," that must yield the subject of any proposition I believe about the object: I do not have to believe that the field is green, that the grass is green, or any such thing. Perception leaves us vast latitude as to what we learn from it. People differ greatly in the beliefs they form about the very same things they see. 2 The concept of objectual perception, then, is very permissive about what one believes about the object perceived. This is one reason why it leaves so much space for imagination and learning—a space often filled by the formation of propositional beliefs, each capturing a different aspect of what is perceived, say that the field is richly green, that it is windblown, and that it ends at a treeline. A different example may bring these points out further. After seeing a distant flare and coming to believe, of something blurry and far away, that it glowed, one might ask, 'What on Earth was it that glowed?' Before we can believe the proposition that a flare glowed, we may have to think about where we are, the movement and fading of the glow, and so forth. The objectual belief is a guide by which we may arrive at propositional beliefs and propositional knowledge. Perception, conception, and belief The same kind of example can be used to illustrate how belief depends on our conceptual resources in a way that perception does not. Suppose I had grown up in the desert and somehow failed to acquire the concept of a field. I could nonetheless see the green field, and from a purely visual point of view it might look the same to me as it does now. I could also believe, regarding the field I see—and perhaps conceive as sand artificially covered with something green—that it is rectangular. But I could not believe that the field is rectangular. This propositional belief as it were portrays what I see as a field in a way that requires my having a concept of one. There is a connection here between thought and language (or at least conceptualization). If I believe (think) that the field is rectangular, or even simply have the thought that it is, I should be able to say that it is and to know what I am talking about. But if I had no concept of a field, then in saying this I would not know what I am talking about. 3 Similarly, a two year old, say, Susie, who has no notion of a tachistoscope, can, upon seeing one and hearing its fan, believe it to be making noise; but she cannot believe specifically that the tachistoscope is making noise. Her propositional belief, if any, would be, say, that the thing on the table is making noise. Since this is true, what she believes is true and she may know this truth, but she need not know much 20 Sources of justification, knowledge, and truth about the object this truth concerns: in a way, she does not know what it is she has this true belief about. The general lesson here is important. A basic mode of learning about objects is to find out truths about them in this elementary way: we get a handle on them through perceptually discriminating some of their properties; we form objectual (and other) beliefs about them from different perspectives; and (often) we finally reach an adequate concept of what they are. From the properties I believe the flare in the distance to have, I finally figure out that it is a flare that has them. This suggests that there is at least one respect in which our knowledge of (perceptible) properties is more basic than our knowledge of the substances that have them; but whether that is so is a question I cannot pursue here. Unlike propositional beliefs, objectual beliefs have a significant degree of indefiniteness in virtue of which it can be misleading simply to call them true or false; they are accurate or inaccurate, depending on whether what one believes of the object (such as that it is rectangular) is or is not true of it. Recall Susie. If she attributes noise-making to the tachistoscope, she truly believes, of it, that it is making noise. She is, then, right about it. But this holds even if she has no specific concept of what it is that is making the noise. If we say unqualifiedly that her belief about it is true, we invite the question 'What belief?' and the expectation that the answer will specify a particular proposition, say that the tachistoscope is making noise. But it need not, and we might be unable to find any proposition that she does believe about it. She can be right about something without knowing or even having any conception of what kind of thing it is that she is right about. Knowledge is often partial in this way. Still, once we get the kind of epistemic handle on something that objectual belief can provide, we can usually use that to learn more about it.4 Suppose I see a dog's tail projecting from under a bed and do not recognize it as such. If I believe it to be a slender furry thing, I have a place to start in finding out what else it is. I will, moreover, be disposed to form such beliefs as that there is a slender furry thing there. I will also have justification for them. But I need not form them, particularly if my attention quickly turns elsewhere. Propositional and objectual perception Corresponding to the two kinds of beliefs I have described are two ways of talking about perception. I see that the field is rectangular. This is (visual) propositional perception: perceiving that. I also see it to be rectangular. This is (visual) objectual perception: perceiving to be. The same distinction apparently applies to hearing and touch. Perhaps, for example, I can hear that a piano is out of tune by hearing its sour notes, as opposed to hearing the tuner say it needs tuning. As for taste and smell, we speak as if they yielded only simple perception: we talk of smelling mint in the iced tea, but not of smelling that it is minty or smelling it to be minty. Such talk is, however, Perception 21 intelligible on the model of seeing that something is so and seeing it to be so. We may thus take the distinction between perceiving that and perceiving to be to apply in principle to all the senses. It is useful to think of perceptual beliefs as embedded in the corresponding propositional or objectual perception, roughly in the sense that they are integrally tied to perceiving of that kind and derive their character and perhaps their authority from their perceptual grounding. Take propositional belief first. My belief that the field is rectangular is embedded in my seeing that it is, and Susie's believing the tachistoscope to be making noise is embedded in her hearing it to be doing so. In each case, the belief is an element in perception of the corresponding kind. These kinds of perception might therefore be called cognitive, since belief is a cognitive attitude: roughly the kind having a proposition (something true or false) as its object. 5 The object of the belief that the field is rectangular is the specific proposition that the field is rectangular, which is true or false. Now consider objectual perceptual beliefs. If believing the tachistoscope to be making noise has a propositional object, that object may be plausibly taken to be some proposition or other to the effect that it is making noise, which (though left unspecified by the ascription of the belief) is also true or false. But some objectual perceptions may also be plausibly conceived as simply attributions of a perceptible property to the thing perceived; here the embedded objectual belief is true of the object rather than simply true. A tiny, prelingual child might see the liquid offered to it to be milk yet not believe (or disbelieve) the proposition that it is milk. In this respect, belief is unlike attitudes of approval or admiration or indignation, which are evaluated not as true or false but rather as, say, appropriate or inappropriate.6 Both propositional and objectual beliefs are grounded in simple perception. If I do not see a thing at all, I do not see that it has any particular property and I do not see it to be anything. Depending on whether perceptual beliefs are propositional or objectual, they may differ in the kind of knowledge they give us. Propositional perception yields knowledge both of what it is that we perceive and of some property of it, for instance of the field's being rectangular. Objectual perception may, in special cases, give us knowledge only of a property of what we perceive, say of its being green, when we do not know what it is or have any belief as to what it is. In objectual perception, we are, to be sure, in a good position to come to know something or other about the object, say that it is a green expanse. Objectual perception may thus give us information not only about objects of which we have a definite conception, such as home furnishings, but also about utterly unfamiliar objects of which we have at most a very general conception, say 'that noisy thing'. This is important. We could not learn as readily from perception if it gave us information only about objects we conceive in the specific ways in which we conceive most of the familiar things we see, hear, touch, taste, and smell.7 22 Sources of justification, knowledge, and truth Seeing and believing Both propositional and objectual perceptual beliefs are commonly grounded in perception in a way that apparently connects us with the outside world and assures their truth. For instance, my visual belief that the field is rectangular is so grounded in my seeing the field that I veridically (truly) see that it is rectangular; my tactually believing the glass to be cold is so grounded in my feeling it that I veridically feel it to be cold. Let us explore the relation between perception and belief. Perceptually embedded beliefs Must beliefs grounded in seeing be true? Admittedly, I might visually (or tactually) believe that something is rectangular under conditions poor for judging it. Compare viewing a straight stick half submerged in water (it will look bent). My visually grounded belief might then be mistaken. But such a mistaken belief is not embedded in propositional perception that the stick is bent—that proposition is false and hence is not something one sees is so (or to be so). The belief is merely produced by some element in the simple perception of the stick: I see the stick in the water, and the operation of reflected light causes me to have the illusion of a bent stick. I thus do not see that the stick is bent: my genuine perception is of it, but not of its curvature. Seeing that curvature or seeing that the stick is bent would entail that it is bent, which is false. If the stick is not bent, I cannot see that it is. As this suggests, there is something special about both perceiving that and perceiving to be. They are veridical experiences, that is, they imply truth. Specifically, if I see that the field is rectangular, or even just see it to be rectangular, then it truly is rectangular. Thus, when I simply see the rectangularity of the field, if I acquire the corresponding embedded perceptual beliefs—if I believe that it is rectangular when I see that it is, or believe it to be rectangular when I see it to be—then I am correct in so believing. Perceiving that and perceiving to be, then, imply (truly) believing something about the object perceived—and so are factive. Does simple perception, perception of something, which is required for either of these more complex kinds of perception, also imply true belief? Very commonly, simple perception does imply truly believing something about the object perceived. If I hear a car go by, I commonly believe a car is passing. But could I not hear it, but be so occupied with my reading that I form no belief about it? Let us explore this. Perception as a source of potential beliefs As is suggested by the case of perception overshadowed by preoccupation with reading, there is reason to doubt that simple perceiving must produce any belief at all. Moreover, it commonly does not produce beliefs even of Perception 23 what would be readily believed if the question arose. Suppose I am looking appreciatively at a beautiful rug. Must I believe that it is not producing yellow smoke, plain though this fact is? I think not; there seems to be a natural economy of nature—perhaps explainable on an evolutionary basis—that prevents our minds from being cluttered with the innumerable beliefs we would have if we formed one for each fact we can see to be the case. This line of thought may seem to fly in the face of the adage that seeing is believing. But properly understood, that may apply just to propositional or objectual seeing. In those cases, perception plainly does entail beliefs. Seeing that golf ball-size hail is falling is (in the sense that it entails) believing it.8 This fact, however, is not only perceptible; it is striking. In any event, could I see the field and believe nothing regarding it? Must I not see it to be something or other, say green? And if so, would I not believe, of it, something that is true of it, even if only that it is a green object some distance away? Consider a different example. Imagine that we are talking excitedly and a bird flies quickly across my path. Could I see it, yet form no beliefs about it? There may be no clearly correct answer. For one thing, although there is much we can confidently say about seeing and believing, 'seeing' and 'believing' are, like most philosophically interesting terms, not precise. They have an element of vagueness. No standard dictionary definition or authoritative statement can be expected either to tell us precisely what they mean or, especially, to settle every question about when they do and do not apply.9 Still, we should be wary of concluding that vagueness makes any significant philosophical question unanswerable. How, then, should we answer the question whether seeing entails believing? A negative response might be supported as follows. Suppose I merely see the bird but pay no attention to it because I am utterly intent on our conversation. Why must I form any belief about the bird? Granted, if someone later asks if I saw a blue bird, I may assent, thereby indicating a belief that the bird was blue. But this belief is not perceptual: it is about a perceptible and indeed has visual content, but it is not grounded in seeing. Moreover, it may have been formed only when I recalled my visual experience of the bird. Recalling that experience in such a context may produce a belief about the thing I saw even if my original experience of the thing did not. For plainly a recollected sensory experience can produce beliefs about the object that caused it, especially when I have reason to gain information about that object. Perhaps one notices something in one's recollected image of the bird, an image merely recorded in the original experience, but one formed no belief about the bird. Granted, perception must produce a sensory experience, such as an image, and granted such an image—and even a recollection of it—is raw material for beliefs; it does not follow that perception must produce beliefs. It might be objected that genuinely seeing an object must produce beliefs, even if we are not conscious of its doing so. How else can perception guide our behavior, as it does when, on seeing a log in our path, we step over it? 24 Sources of justification, knowledge, and truth One answer is that not everything we see, including the bird that flies by as I concentrate on something else, demands or even evokes a cognitive response, particularly one entailing belief-formation. If I am cataloguing local birds, the situation is different. But when an unobtrusive object we see—as opposed to one blocking our path—has no particular relation to what we are doing, perhaps our visual impressions of it are simply a basis for forming beliefs about it should the situation call for it, and it need not produce any belief if our concerns and the direction of our attention give the object no significance. Despite the complexity I am pointing to in the relation between seeing and believing, clearly we may hold what is epistemologically most important here. Suppose I can see a bird without believing anything about (or of) it. Still, when I do see one, I can see it to be something or other, and my perceptual circumstances are such that I might readily both come to believe something about it and see that to be true of it. Imagine that someone suddenly interrupts a conversation to say, 'Look at that bird!' If I see it, I am in a position to form some belief about it, if only that it is swift, though I need not actually form any belief about it, at least not one I am conscious of. To see these points more concretely, imagine I am alone and see the bird in the distance for just a second, mistakenly taking it to be a speck of ash. If there is not too much color distortion, I may still both know and justifiedly believe it to be dark. Granted, I would misdescribe it, and I might falsely believe that it is a speck of ash. But I could still know something about it, and I might point the bird out under the misleading but true description, 'that dark thing'. The bird is the thing I point at; and I can see, know, and justifiedly believe that there is a dark thing there. My perception of the bird, then, gives me a ready basis for some knowledge and justification, even if the perception occurs in a way that does not cause me to believe that there is, say, a bird before me and so does not give me actual knowledge of it. Seeing is virtual believing, or at least potential believing. A similar point holds for simple perception in the other senses, though some, such as smell, are in general less richly informative than sight.10 The perceptual hierarchy Our discussion seems to show that simple perceiving need not produce belief, and objectual perceiving need not always yield propositional perceiving. Still, this third kind of perception is clearly not possible without the first and, I think, the second as well. I certainly cannot see that the bird is anything if I do not see it at all; and I must also see it in order to see it to be something, say a speck of blue. Thus, simple perceiving is fundamental: it is required for objectual and propositional perceiving, yet does not clearly entail either. If, for instance, you do not perceive in the simple mode, say see a blue speck, you do not perceive in the other two modes either, say see a speck to be blue or see that it is blue. And as objectual perceiving seems possible without Perception 25 propositional perceiving, but not conversely, the former seems basic relative to the latter. Simple, objectual, and propositional perception We have, then, a perceptual hierarchy: propositional perceiving depends on objectual perceiving, which in turn depends on simple perceiving. Simple perceiving is basic, and it commonly yields, even if it need not always yield, objectual perceiving, which, in turn, commonly yields, even if it need not always yield, propositional perceiving. Simple perceiving, such as just seeing a green field, may apparently occur without either of the other two kinds, but seeing something to be anything at all, such as rectangular, requires seeing it; and seeing that it is something in particular, say green, requires both seeing it to be something and, of course, seeing it. Thus, even if simple perception does not always produce at least one true belief, it characteristically does position us to form any number of true beliefs. It gives us cognitive access to perceptual information, perhaps even records that information in some sense, whether or not we register the information conceptually by forming perceptual beliefs of either kind. The informational character of perception As this suggests, perception by its very nature is informational; it might even be understood as equivalent to a kind—a sensory kind—of receipt of information about the object perceived.11 The point here is that not all perceptually given information is propositional or even conceptualized. This is why we do not receive or store all of it in the contents of our beliefs. Perceptual content—conceived as the content of a simple perception—is at least in part determined by the properties we are sensorily conscious of in having that experience; it is not equivalent to the content of the perceptual belief(s) that experience may produce. Some of the information perception yields is imagistic. Indeed, we may think of all the senses as capable of yielding images or, for the non-visual senses, at least of yielding the non-visual counterparts of images—percepts, to use a technical term for such elements in perceptual experience occurring in any sensory mode, whether visual or auditory or of some other kind. It is in these sensory impressions that the bulk of perceptual information apparently resides. This point explains the plausibility of the idea that a picture is worth a thousand words—which is not to deny that, for some purposes, some words are worth a thousand pictures. A single report of smoke may avert a catastrophe; a single promise may alter a million lives. It is in part because perception is so richly informative that it normally gives us not only imagistic information but also situational justification. Even if I could be so lost in conversation that I form no belief about the passing bird, I am, as I see it pass, normally justified in believing something about it, 26 Sources of justification, knowledge, and truth concerning its perceptible properties, for instance that it glides.12 There may perhaps be nothing highly specific that I am justified in believing about it, say that it is a cardinal or that its wingspan is ten inches, but if I really see it, as opposed to its merely causing in me a visual impression too indistinct to qualify me as seeing it, then there is something or other that I may justifiably believe about it. When we have a clear perception of something, it is even easier to have perceptual justification for believing a proposition about it without actually believing it. Just by taking stock of the size of the field in clear view before me, I am justified in believing that it has more than 289 blades of grass; but I do not ordinarily believe—or disbelieve—any such thing about grassy fields I see. It was only when I sought a philosophical example about perception and belief, and then arbitrarily chose the proposition that the field has more than 289 blades of grass, that I came to believe this proposition. Again, I was justified in believing the proposition before I actually did believe it. Perceptual justification and perceptual knowledge What is it that explains why seeing the bird or the field justifies us in believing something about what we see, that is, gives us situational justification for such a belief? And does the same thing explain why seeing something enables us to know various facts about it? Seeing and seeing as One possible answer is that if we see something at all, say a bird, we see it as something, for instance black or large or swift, and we are justified in believing it to be what we see it as being. The idea is that all seeing and perhaps all perceiving is aspectual perception of a kind that confers justification. We see things by seeing their properties or aspects, for instance their colors or their front sides, and we are justified in taking them to have the properties or aspects we see them as having. Let us not go too fast. Consider two points, one concerning the nature of seeing as, the other its relation to justification. First, might not the sort of distinction we have observed between situational and belief justification apply to seeing itself? Specifically, might not my seeing the bird imply that I am only in a position to see it as something, and not that I do see it as something? It is true that when we see something, we see it by seeing some property or aspect of it; but it does not follow that we see it as having this property or aspect. I might see a van Gogh painting by its colors, shapes, and distinctive brush strokes, but not see it as having them because my visual experience is dominated by the painting as a whole. Someone might reply that if I see it by those properties, I am disposed to believe it has them and so must see it as having them; but this disposition Perception 27 implies at most a readiness to see it as having them. There may, to be sure, be a sense in which if we see something aright, for example see a van Gogh with recognition of it as his, then we must see it as what we recognize it to be. Seeing as can also be a matter of conceptualization—roughly, conceiving as. But this is different from perceptual seeing as. The distinction between perceptual seeing as and perceptual seeing by remains. Seeing by is causal and discriminative but not necessarily ascriptive or, especially, conceptual. Seeing as, though also causal, is often ascriptive and commonly conceptual. We see faces by seeing (for example) the distinctive shape of the eyes and mouth, but need not ascribe those to those we see or conceptualize these properties. But if we see a painting as blurry, we commonly ascribe that property to it and may conceptualize the painting as blurry. Second, suppose that seeing the bird did imply (visually) seeing it as something. Clearly, this need not be something one is justified in believing it to be (and perhaps it need not be something one does believe it to be). Charles, our biased birdwatcher, might erroneously see a plainly black bird as blue, simply because he so loves birds of blue color and so dislikes black birds that (as he himself knows) his vision plays tricks on him when he is bird-watching. He might then not be justified in believing that the bird is blue. Assume for the sake of argument that seeing implies seeing as and that typically, seeing as implies at least objectually believing something or other about the thing seen. Still, seeing an object as having a certain property—say, a stick in the water as bent—does not entail that it has the property. Nor does it always give one (overall) situational justification for believing it to have that property. Perceptual content It is natural to think of perception as in some way representational. If we see things by seeing their properties, for instance, then our perceptual experience in some way represents the object as having them. If perceiving entailed believing, we could perhaps take it to have the same content of the entailed belief(s). But (simple) perception apparently does not entail believing, so this conception of its content is mistaken. For propositional and objectual perception, however, we might plausibly say something like this: the content of my perception that p includes both the proposition that p (hence also the content of that proposition) and also the content of my objectual perception of the thing in question; that content includes the properties I perceive the thing to have. If we seek a broad notion of perceptual content for simple perception, we might say that all the properties represented in a perceptual experience constitute its content. Then, for greater specificity, we might call the totality of perceptually represented properties the property content. These include properties an object is seen as having.13 They apparently also determine "what it 28 Sources of justification, knowledge, and truth is like" to perceive the object, say a squirrel in a tree. In seeing it, one's visual field is determined mainly by the grey, the distinctive furry shape, and the arboreal background. For propositional and objectual perception, we might call the propertyascriptive propositions that the perceiver perceptually believes on the basis of the perceptual experience their doxastic propositional content. If we want to capture all the propositions that one might justifiedly believe (and know) on the basis of the perception, we might speak of its total propositional content. This would include such propositions as that the squirrel is crouching, has a nut in its mouth, is in sunlight, and many more that need not be believed as a result of simply seeing the animal.14 Seeing as and perceptual grounds of justification Whether or not seeing always implies seeing as, it does have property content and normally puts one in a position to form at least one justified belief about the object seen. Suppose I see the bird so briefly and distractedly that I do not see it as anything in particular; still, my visual impression of it has some feature or other by which I am justified in believing something of the bird, if only that it is a moving thing. Even Charles would be justified in believing something like this. His tendency to see black birds as blue is irrelevant to his perception of movement and does not affect his justification for believing such moving objects to be in motion. Suppose, however, th