This edition first published 2017
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Library of Congress Cataloging-in-Publication Data
Names: Foresman, Galen A., author.
Title: The critical thinking toolkit / Galen A. Foresman, Peter S. Fosl, and Jamie C. Watson.
Description: Hoboken : Wiley, 2016. | Includes bibliographical references and index.
Identifiers: LCCN 2016006532 (print) | LCCN 2016012956 (ebook) | ISBN 9780470659960 (cloth) |
ISBN 9780470658697 (pbk.) | ISBN 9781118982020 (pdf) | ISBN 9781118981993 (epub)
Subjects: LCSH: Reasoning. | Critical thinking. | Logic.
Classification: LCC BC177 .F67 2016 (print) | LCC BC177 (ebook) | DDC 160—dc23
LC record available at http://lccn.loc.gov/2016006532
A catalogue record for this book is available from the British Library.
Cover image: Getty/© Lisa Quarfoth
To our students and to the Logos
The authors would like to thank in the first place our families for their patience as we labored on this book. Without their support, inspiration, and advice this project would not have come to fruition. In particular, we wish to thank Cate Fosl and Darlena Watson. We are especially grateful to Robert Arp for getting the ball rolling on this project, as well as to editors Jeff Dean and Liam Cooper for making sure it kept rolling.
We thank Julian Baggini, too, for graciously permitting us to extend the Toolkit program to the field of critical thinking and for permitting us to rework material drawn from a number of entries in The Philosopher's Toolkit for this text. We thank Nathan Gray and Nathan Eric Dickman (Young Harris College) as well as Robert Bass (University of North Carolina, Pembroke) for valuable insights and examples. We thank Kevin Decker for his close reading and helpful criticisms. One of the greatest critical thinkers we know, Jamie Miller, offered us helpful advice, pedagogical as well as logical. Cate Fosl (University of Louisville) offered important insights on matters of race and feminism. Jack Furlong and Bob Rosenberg (Transylvania University) helped refine sections dealing with the natural sciences. Alexander Dick (University of British Columbia) advised the authors on topics in critical theory.
We are grateful, too, to the institutions that have supported our academic work: North Carolina Agricultural & Technical State University, Transylvania University, and Broward College. We are also grateful, more generally, for the continued existence of institutions of higher education that sustain the cultivation and communication of critical thinking. Our civilization depends deeply upon those efforts and on the support of donors, governments, and students. The professors who introduced us to logic and critical thinking deserve special acknowledgment, as we recognize that it is most immediately and perhaps most crucially through the efforts of fine teachers such as they are that good, clear, and critical thinking is cultivated in our world and passed on to new generations. Outstanding instruction in logic was afforded to us by Professor Frank Wilson at Bucknell University, by Burke Townsend at the University of Montana, Piers Rawling at Florida State University, and by Michael Bradie at Bowling Green State University. They in turn learned from fine and able teachers and inquirers into logic, epistemology, criticism, the sciences, and psychology in a weave of traditions that stretches back to antiquity. We hope in some small way to carry on those traditions in this volume. Any errors or shortcomings it presents are wholly our own.
Wiley deserves our deep gratitude not only for publishing our work but also for advancing and sustaining thoughtful publications at a time when doing so is increasingly complex and difficult. No book produced through a fine publisher is realized without the guidance of its editors, and we have been especially fortunate in the editing provided by Alison Kostka, Liam Cooper, and Sally Cooper. We are grateful for the keen eyes and good judgment of copy editor Fiona Screen and proofreader Helen Kemp, for the talents of the artists who produced the book's cover, as well as for the marketing and distribution teams that have made this text available to readers. We salute you all!
Critical thinking sometimes seems as if it needs an apology, or rather it seems itself to be a kind of apology, an apology for the humanities and the liberal arts and sciences generally. Having failed to convince many people that the liberal arts are simply good in themselves or in their own terms, academics sometimes seem as though they have concocted the meretricious idea of “critical thinking” in order to help higher education sell itself to the worlds of commerce, law, and politics. Instead of arguing that the liberal arts comprise some of the very best ways to spend a human life, period (and that we ought, therefore, to support them enthusiastically and share them as widely as possible), academics seem inclined to wave the flag of critical thinking to convince governments, parents, students, and donors that the liberal arts offer something that's “useful” or “profitable” in the “real” world.
Critical thinking also seems to appeal to administrators and the administratively inclined because it poses as something testable, as composed of skills that produce “measurable outcomes” readily subject to “metrics” and “assessment.” Yielding measurable, quantifiable outcomes is important not only for demonstrating to those outside the academy the value of critical thinking and the liberal arts but also for “accountability,” for oversight, for ranking and managing, and perhaps for policing liberal arts faculties.
There is truth in all this, embarrassingly so. But it's not the whole story about critical thinking (or the liberal arts), not by a long shot. The authors of this book are convinced that the family of practices collected under the rubric of “critical thinking” does indeed include some of the best and most important activities human beings have forged and re-forged, shaped and refined over the last three millennia. It's not too much to say, in our view, that critical thinking distills some of the very best of that inheritance. In the development of our sciences, our political institutions, and our very self-understandings, critical thinking has played a central role, and it's simply fine and good to pass on that treasure to future generations. What has been true of our history remains true today: strong critical thinking is not only useful for commerce, the law, and technology, it's absolutely crucial to a dynamic and thriving culture, and it defines an essential component of any solid education.
But what is critical thinking? What composes it? In this volume, we've taken a broad, interdisciplinary, and relatively comprehensive approach to critical thinking. While many critical thinking texts focus almost exclusively on logical topics, we've also compiled critical insights and practices that have been cultivated by the natural and social sciences, notably psychology, by literature and literary criticism as well as by the fine arts, and by political and social theories. We treat literature, rhetoric, and the arts not simply as obstructions or distractions that get in the way of clear, analytical, and logical thinking ‒ though they sometimes can do that. We recognize in addition that the visual, literary, and generally rhetorical arts possess distinctive tools to enhance and deepen critical thinking. While the critical tools developed by philosophers, logicians, mathematicians, and empirical scientists are extremely important to good critical thinking, the critical instruments honed by theorists in literary, political, and social theory have been profound. No account of the possible methods of critical thinking available today would be respectable or even roughly complete without them. Arguments are, indeed, terribly important, but they're not by any means the whole story of critical thinking. We encourage readers, therefore, to take a similarly broad, interdisciplinary, and inclusive approach and to consider the diverse ways critical thinking has been cultivated across the spectrum of reflective human thought.
Considering the structure of this book, we begin with logic, since logic is basic and essential to critical thinking. Chapters 1‒4 of this ten-chapter volume are accordingly devoted to explaining some of the most important critical tools logicians have crafted, especially for the practices of what they call deductive reasoning. These techniques can seem a bit daunting to beginners, but because logic is so important we encourage you to press on through them. Logicians have studied the formal qualities of deductive inferences over thousands of years, and they've produced several logical systems that critical thinkers can use to test arguments. Those tests are not only indispensible tools for critical thinking. They also share the virtue of producing definite answers about good and bad reasoning using procedures that are clear, reliable, and not terribly difficult to use.
The oldest of these systems we'll address (Chapter 3) was systematized first by Aristotle in fourth-century BCE Greece. It's come to be called categorical logic since it's a logic that's based upon categories of things. We'll map out seven tests for the validity of arguments using categorical logic. Those seven by themselves will provide critical thinkers with a rich and powerful set of tools to interpret and assess vast regions of human reasoning.
Yes, humans seem to possess a natural capacity for recognizing good reasoning even without studying critical thinking in a formal way, but the systems we present are important to master because they make it possible for skilled critical thinkers to build on that natural capacity and employ proven and useful rules in expansive ways ‒ including articulating proper explanations and definitions, determining logical equivalences, and identifying contraries and contradictions, as well as a variety of other logical relationships. We'll explain and demonstrate the use of helpful pictographic tests using Venn diagrams and Gensler stars, and after setting out some basic logical theory we'll show you how to apply a number of simple procedures for reliably identifying valid and invalid arguments almost in a snap.
The second principal kind of formal logic we'll address (Chapter 4) has come to be called propositional or sentential logic ‒ because, yes, it's the logic of propositions or whole sentences. These sections will present you with additional ways to test arguments, especially through what logicians call truth tables, common forms of valid argument, and tried-and-true rules of inference. Truth tables are attractive to people because they offer a graphical way of testing arguments, and one that's simplicity is perhaps even more exhaustive and direct than Venn diagrams. Learning the formal structures of the most common valid as well as invalid arguments together with what we think is an essential collection of other inference rules will help you sharpen the focus of your reasoning detectors so that the success or failure of arguments becomes much more easily recognizable.
Chapter 5 sets out a substantial list of some of the most common ways people go wrong in their daily reasoning. These common informal fallacies aren't failures of the formal or structural dimensions of arguments (the stuff of Chapters 3‒4), but rather failures of another kind. Sometimes what goes wrong in reasoning isn't a matter of argument form at all but instead often involves psychological factors that yield quasi-inferences that pose as good reasoning but simply aren't. Sometimes, alternatively, the problem lies with the underlying concepts and assumptions behind a claim. Those concepts and assumptions can be irrelevant, confused, or simply false, and as we'll see they can really mess up your reasoning. Good critical thinking skills of the sort described in Chapter 5 have been designed to detect them, and there are many of them. Because some informal fallacies are particularly related to scientific thinking, we'll broach additional informal fallacies across the remaining text, especially in those chapters devoted more directly to inductive reasoning and the empirical sciences.
There are sadly, then, a lot of ways that reasoning can go wrong. The modern natural and social sciences were born from a struggle to deal with many of these kinds of error while simultaneously trying both to understand the world and to answer the philosophical challenge of skepticism ‒ the idea that knowledge itself might not be possible. As a result of those challenges, scientists and philosophers of science developed important ideas regarding what counts in terms of empirical inquiry as good explanation and solid justification. We'll therefore examine what makes scientific forms of inquiry so strong, and we'll also look at how science can go wrong. Chapters 6‒9 will draw lessons in critical thinking from the natural and social sciences as well as from ongoing philosophical confrontations with skepticism. We'll examine how best to confront the epistemological challenges of skepticism, how to think well and critically about causal explanations and statistical claims, how to enlist scientific principles critically, how to think critically even about science itself, and we'll consider what science has learned about why human beings make errors. Critical thinkers should certainly be able to assess non-scientific claims using scientific rationality, but they should also possess some facility with assessing scientific claims themselves.
Human beings are linguistic beings. We communicate, reason, and criticize using language, and the critical theories developed by scholars in fields related to rhetoric, languages, and literature have gone a long way toward explaining not only how communication works but also how it fails to work ‒ that is, how language and our human modes of expression themselves create, even require, the possibility of error, confusion, and misunderstanding. The meanings we wish to express are difficult to express. They're elusive and fragile and complicated. We all know this on some level, but critical thinkers must become especially sensitive to it. Narratives, poetic tropes, voice, and other rhetorical dimensions of texts, however, not only offer opportunities for error and distortion. They also yield indispensible ways of understanding our selves and our world. Chapter 10 is designed therefore to help you consider critically the rhetorical and semiotic dimensions of the world in whatever text you confront ‒ and not just in a theoretical way. Like our other chapters, Chapter 10 offers examples and problems for you to use in putting these tools to work.
Human practices of expression are also tied up with political relations. We are, as Aristotle observed, political animals. Moreover, political theorists, especially across the past few centuries, have come to understand that politics doesn't only exist in the halls of government, in voting booths, on explicitly political Internet web sites, or on clearly political TV or radio talk shows. Politics is, rather, pervasive and infuses our ordinary language, our concepts, our conduct, indeed the very institutions that compose our societies and cultures broadly speaking. Engaging political as well as moral topics critically, therefore, may involve not only thought but also action.
Political action may be a matter of subversion and destabilization, of prising open spaces for new ways of life, and deconstructing what we determine needs to change. It may also, however, be about justifying and stabilizing values, principles, and moral claims ‒ those that already exist and we think it important to keep, to protect, and to secure. In order for readers to engage their own political world more effectively, in addition to questions related to justification and values in Chapter 6‒9 we also lay out tools drawn from political theory in Chapter 10. We don't presume the political theories we describe to exhaust the field of political thought, and we don't necessarily endorse them ourselves, but we do think these are among the most important critical approaches today, and it's necessary for able critical thinkers to gain some facility with them.
Strong critical thinkers, in sum, should be able not only to wield the tools of logic and science but also those that illuminate the complexities of language and communication as well as those that help confront, advance, or resist the principal forms of morality and politics at work in the world today. Critical thinking should not only be directed toward improved inquiry into questions of truth and falsehood but also into issues of meaning more generally as well as imperatives and possibilities of moral and political action.
There's something else. We wish to make it clear that critical thinking, like our book as a whole, is about self-understanding. It's part of that ancient project enshrined in the inscription on the temple at Delphi and in the liberal arts and sciences: “know thyself.” Using critical thinking we produce critiques not just of arguments, data sets, propositions, and texts in the abstract. We also produce critiques that reveal our limits, our weaknesses, our finitude, and our selves as we actually exist in the world. Thinking about the world, about others, and about ourselves in light of a reflective and critical self-understanding of the human condition may be even more important than winning arguments or unreflectively accumulating facts, wealth, or power. It may, indeed, be the most important critical thinking outcome of all.
This volume is not a complete text in logic, cognitive psychology, epistemology, critical theory, or political and social theory. The world of ideas is vast. We have collected what we think are the essentials for a basic grasp of critical thinking, and we have compressed, so far as possible, our entries to provide you with substantial and sophisticated but also concise accounts of the tools we address. You may read the text sequentially since it follows an arc from the positive establishment of claims through the complexities of logical and scientific thinking and reasoning to, finally, a critical denouement in rhetoric and politics. But the text may be read in other ways, too. You may start anywhere and either follow your own muses or fork off onto the network of paths we recommend using the suggested “See also” pointers at the close of most entries and chapters.
You will often see us referring in the body of the text to the preceding toolkits in this series: The Philosophers Toolkit and The Ethics Toolkit. That's because we understand these books to work together synergistically with ours, and those books often offer entries that complement and enrich our own. Some of the entries of this volume overlap with entries in those other toolkits (and we are grateful to Julian Baggini for permission to do that), and so together we think they offer a kind of functional whole of critical and philosophical thinking. But this volume stands on its own, too, very much so; and it offers readers a fine gateway all its own to these powerful, critical tools.
Our book also contains larders of examples and problems for study and exercise. These may be enlisted by instructors in their class preparation or simply by readers for further reflection. As we've not always provided answers to these problems and questions, they're as much matters of provocation as instruction. A list of web sites at the end of the volume suggests additional resources relevant to critical thinking freely available on the Internet.
Know thyself and think critically.