McGraw-Hill Higher Education CRITICAL THINKING. NINTH EDITION Published by McGraw-Hill, an imprint of The McGraw-Hill Companies, Inc, 1221 Avenue of the Americas, New York, NY 10020. Copyright o 2009 by The McGraw-Hill Companies, Inc. All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or teval system, without the prior written consent of The McGraw-Hill Companies, Inc, including, but not limited to, in any network or other electronic storage or transmission, or broadcast for distance leaming Some ancillaries, including electronic and print components, may not be available to customers outside the This book is printed on acid-free paper. 1234567890VNH/VNH098 ISBN978-0-07-128041-9 MHD0-07128041-3
Revised Pages CRITICAL THINKING, NINTH EDITION Published by McGraw-Hill, an imprint of The McGraw-Hill Companies, Inc., 1221 Avenue of the Americas, New York, NY 10020. Copyright © 2009 by The McGraw-Hill Companies, Inc. All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of The McGraw-Hill Companies, Inc., including, but not limited to, in any network or other electronic storage or transmission, or broadcast for distance learning. Some ancillaries, including electronic and print components, may not be available to customers outside the United States. This book is printed on acid-free paper. 1 2 3 4 5 6 7 8 9 0 VNH / VNH 0 9 8 ISBN 978-0-07-128041-9 MHID 0-07-128041-3 www.mhhe.com moo86677_fm_ise.indd ii 7/4/08 11:54:04 AM
Chapter Critical Thinking Basics Butte city n the previous edition, we spoke of Butte City, California, a small agricultural town located between Princeton and Ord Bend where Highway 162 crosses the Sacramento River. Butte Ci Ity never was a real city, and now even the saloon and general store are boarded up and for sale. Abandoned pieces of farm equipment rust along the highway We mentioned a new business in Butte City, a tanning salon. We are sorry to report that the salon, too, has gone under. The Sacramento Val ley gets enough sun to melt the blacktop in the summertime; residents of Butte City might pay to get less of it, but it's unlikely theyd pay to get more. Some critical thinking surely would have turned up the flaws in the salons business plan. regularly take his advice and stare directly into suru Hira Ratan Manek this practice would provide energy and clarity of thought, but ophthal mologists as well as critical thinkers will tell you it's more likely to dam age your eyes Police were chasing a man in Chicago when they ran past a garage with its door wide open. Inside was a man bagging $670,000 worth of marijuana. Three suspects were arrested on charges of possession with "Atlanta JoumakConstitution, August 7, 2007
Confi rming Pages I n the previous edition, we spoke of Butte City, California, a small agricultural town located between Princeton and Ord Bend where Highway 162 crosses the Sacramento River. Butte City never was a real city, and now even the saloon and general store are boarded up and for sale. Abandoned pieces of farm equipment rust along the highway. We mentioned a new business in Butte City, a tanning salon. We are sorry to report that the salon, too, has gone under. The Sacramento Valley gets enough sun to melt the blacktop in the summertime; residents of Butte City might pay to get less of it, but it’s unlikely they’d pay to get more. Some critical thinking surely would have turned up the flaws in the salon’s business plan. In Atlanta, some fifty followers of Indian guru Hira Ratan Manek regularly take his advice and stare directly into the sun. Manek told them this practice would provide energy and clarity of thought, but ophthalmologists as well as critical thinkers will tell you it’s more likely to damage your eyes. * Police were chasing a man in Chicago when they ran past a garage with its door wide open. Inside was a man bagging $670,000 worth of marijuana. Three suspects were arrested on charges of possession with * Atlanta Journal-Constitution, August 7, 2007. Chapter 1 Critical Thinking Basics moo86677_ch01_001-040.indd 1 6/17/08 10:31:01 AM
intent to sell. Even a modest level of critical thinking would lead one to close he garage door before doing ones mischief Because he believed it had worked for him, a fellow one of us once knew by the name of Ross, thought that eating Vicks VapoRub was a sure cure for colds. Despite warnings on the bottle not to take it internally, Ross recom mended about a tablespoon. "Eat that, " he'd say, " and your cold disappears. It may have seemed to work for Ross, but generally speaking, colds tend to disappear of their own accord after a few days. Eat nearly anything and your cold disappears. Eat dirt and your cold disappears Cases like these are everywhere, despite the fact that human beings are clever enough to land spacecraft on a moon of Jupiter, to combine genetic mate rial to alter life forms, and to build computers that outplay grand masters at chess. But our remarkable intellectual accomplishments stand side by side with our bad judgments and our foolishness. Astronaut Lisa Nowak, presumably no mumMy in most aspects of her life, allegedly drove from Houston to Orlando Florida, wearing a diaper (so she wouldnt need restroom stops) to confront a rival for the affections of another astronaut, William Oefelein. According to police, she possessed a large knife, pepper spray, and a bB gun with which to threaten the other woman. Her reputation and her career as an astronaut in ruins as a result, Ms Nowak illustrates how reason can take the day off once we let our emotions, our prejudices, or a bad idea get the upper hand. WHAT IS CRITICAL THINKING? As human beings, we are not doomed to reach conclusions and make deci sions like the ones in these examples. Our primary tool in making better judg ments is critical thinking. We provide a fairly thorough list of the elements of Thinking critically, the photographer used remote control to shoot this gem ChicagoSun-iimes,June28,2007.nEwsoftheweird.com
Confi rming Pages 2 CHAPTER 1 CRITICAL THINKING BASICS intent to sell.* Even a modest level of critical thinking would lead one to close the garage door before doing one’s mischief. Because he believed it had worked for him, a fellow one of us once knew, by the name of Ross, thought that eating Vicks VapoRub was a sure cure for colds. Despite warnings on the bottle not to take it internally, Ross recommended about a tablespoon. “Eat that,” he’d say, “and your cold disappears.” It may have seemed to work for Ross, but generally speaking, colds tend to disappear of their own accord after a few days. Eat nearly anything and your cold disappears. Eat dirt and your cold disappears. Cases like these are everywhere, despite the fact that human beings are clever enough to land spacecraft on a moon of Jupiter, to combine genetic material to alter life forms, and to build computers that outplay grand masters at chess. But our remarkable intellectual accomplishments stand side by side with our bad judgments and our foolishness. Astronaut Lisa Nowak, presumably no dummy in most aspects of her life, allegedly drove from Houston to Orlando, Florida, wearing a diaper (so she wouldn’t need restroom stops) to confront a rival for the affections of another astronaut, William Oefelein. According to police, she possessed a large knife, pepper spray, and a BB gun with which to threaten the other woman. Her reputation and her career as an astronaut in ruins as a result, Ms. Nowak illustrates how reason can take the day off once we let our emotions, our prejudices, or a bad idea get the upper hand. WHAT IS CRITICAL THINKING? As human beings, we are not doomed to reach conclusions and make decisions like the ones in these examples. Our primary tool in making better judgments is critical thinking. We provide a fairly thorough list of the elements of * Chicago Sun-Times, June 28, 2007. Newsoftheweird.com. ■ Thinking critically, the photographer used remote control to shoot this gem. moo86677_ch01_001-040.indd 2 6/17/08 10:31:10 AM
WHAT IS CRITICAL THINKING? In Depth Critical Thinking, the Long Version In the text, we give a couple of brief characterizations of critical thinking, and as shorthand they will serve well enough. But the Collegiate Learning Assessment(CLA) Project of the Council for Aid to Education has come up with a list of skills that covers almost everything your authors believe is important in critical thinking. If you achieve mastery over all these or even a significant majority of them, you'll be well ahead of most of your peers-and your fellow citizens. In question form, here is what the council came up with How well does the student a determine what information is or is not pertinent; distinguish between rational claims and emotional ones; separate fact from opinion recognize the ways in which evidence might be limited or compromised, spot deception and holes in the arguments of others present his/her own analysis of the data or information recognize logical flaws in arguments draw connections between discrete sources of data and information attend to contradictory, inadequate, or ambiguous information construct cogent arguments rooted in data rather than opinion; select the strongest set of supporting data; avoid overstated conclusions. identify holes in the evidence and suggest additional information to collect; recognize that a problem may have no clear answer or single solution; propose other options and weigh them in the decision consider all stakeholders or affected parties in suggesting a course of action; articulate the argument and the context for that argument; correctly and precisely use evidence to defend the argument; logically and cohesively organize the argument, avoid extraneous elements in an argument's development present evidence in an order that contributes to a persuasive argument? chttp://www.aacu.org/peerreview/pr_spo7_analysisl.cfm> critical thinking in the box "Critical Thinking, the Long Version")above. Why do reason, logic, and But, boiled down, critical thinking is the careful application of reason in the truth seem to play a dimin determination of whether a claim is true. Notice that it isn' t so much coming now makes important up with claims, true or otherwise, that constitutes critical thinking; it's the decisions? evaluation of claims, however we come up with them. You might say that -AL GoRE. The Assault on our subject is really thinking about thinking-we engage in it when we con- Reason sider whether our ideas really make good sense. Of course, since our actions We wish it weren't true usually depend on what thoughts or ideas we've accepted, whether we do the intelligent thing also depends on how well we consider those thoughts and ideas
Confi rming Pages critical thinking in the box (“ Critical Thinking, the Long Version ”) above. But, boiled down, critical thinking is the careful application of reason in the determination of whether a claim is true. Notice that it isn’t so much coming up with claims, true or otherwise, that constitutes critical thinking; it’s the evaluation of claims, however we come up with them. You might say that our subject is really thinking about thinking—we engage in it when we consider whether our ideas really make good sense. Of course, since our actions usually depend on what thoughts or ideas we’ve accepted, whether we do the intelligent thing also depends on how well we consider those thoughts and ideas. Why do reason, logic, and truth seem to play a diminished role in the way America now makes important decisions? — AL GORE, The Assault on Reason We wish it weren’t true. . . . Why do reason, logic, and truth seem to play a diminished role in the way America now makes important decisions? — AL GORE, The Assault on Reason We wish it weren’t true. . . . WHAT IS CRITICAL THINKING? 3 In the text, we give a couple of brief characterizations of critical thinking, and as shorthand they will serve well enough. But the Collegiate Learning Assessment (CLA) Project of the Council for Aid to Education has come up with a list of skills that covers almost everything your authors believe is important in critical thinking. If you achieve mastery over all these or even a significant majority of them, you’ll be well ahead of most of your peers—and your fellow citizens. In question form, here is what the council came up with: How well does the student ■ determine what information is or is not pertinent; ■ distinguish between rational claims and emotional ones; ■ separate fact from opinion; ■ recognize the ways in which evidence might be limited or compromised; ■ spot deception and holes in the arguments of others; ■ present his /her own analysis of the data or information; ■ recognize logical flaws in arguments; ■ draw connections between discrete sources of data and information; ■ attend to contradictory, inadequate, or ambiguous information; ■ construct cogent arguments rooted in data rather than opinion; ■ select the strongest set of supporting data; ■ avoid overstated conclusions; ■ identify holes in the evidence and suggest additional information to collect; ■ recognize that a problem may have no clear answer or single solution; ■ propose other options and weigh them in the decision; ■ consider all stakeholders or affected parties in suggesting a course of action; ■ articulate the argument and the context for that argument; ■ correctly and precisely use evidence to defend the argument; ■ logically and cohesively organize the argument; ■ avoid extraneous elements in an argument’s development; ■ present evidence in an order that contributes to a persuasive argument? <http: // www.aacu.org /peerreview /pr_sp07_analysis1.cfm> In Depth Critical Thinking, the Long Version moo86677_ch01_001-040.indd 3 6/17/08 10:31:12 AM
Attempting to debate with a Developing the willingness and the ability to apply the critical thinking person who has abandoned skills found in this book will make you smarter. Not smarter in some particu reason is I like giving mediaine to the dead ar subject, mind you, just smarter in general. The things you learn from this book (and from the course you may be reading it for) are applicable to nearly UNIDENTIFIED EMAILER any subject people can talk or think about. The same principles that apply to your everyday decisions Whose critical thinking class should I take, Moore's or Parker's? )also apply to issues of worldwide importance(Should the United States invade Iran? Is global warming a serious threat? ) In matters both big ■ A rescue team In and small, the more critical thinking that goes on, the better action. Bad luck-and bad judgment-can have grave If Ross had known about the fallacy of post hoc, perhaps he would not have reached his conclusion about Vicks VapoRub. If Ms Nowak had con- consequences sidered the likely tight not have set out on her nine - hundred-mile drive. Had our folks in Butte City bvious relevant fa tors into consideration, they migl have opened a business with a bet ter chance of success. If our guru smitten Atlantans had thought about how bizarre the claim is that taring at the sun can bring cla of thought, they might have saved You may not have done anything quite so witless as the actions described in our exam ples. But everybody makes errors of judgment from time to time The wise person is the one who wishes to keep such errors to a minimum and who knows how to do it. We hope this book helps make you a little wiser One last thing before we If book for a course. chances are you will be expected to critique others' ideas, and they will be asked to critique yours. Every screening o es own ideas for defects and deficiencies although so), bu people draw a line when it comes to subjecting the views of others to scrutiny. Doing this is some times seen as a kind of personal attack."Everyone is entitled his or her opinion, "you often
Confi rming Pages 4 CHAPTER 1 CRITICAL THINKING BASICS Developing the willingness and the ability to apply the critical thinking skills found in this book will make you smarter. Not smarter in some particular subject, mind you, just smarter in general. The things you learn from this book (and from the course you may be reading it for) are applicable to nearly any subject people can talk or think about. The same principles that apply to your everyday decisions (Whose critical thinking class should I take, Moore’s or Parker’s?) also apply to issues of worldwide importance (Should the United States invade Iran? Is global warming a serious threat?). In matters both big and small, the more critical thinking that goes on, the better. If Ross had known about the fallacy of post hoc, perhaps he would not have reached his conclusion about Vicks VapoRub. If Ms. Nowak had considered the likely consequences of her actions, she might not have set out on her nine-hundred-mile drive. Had our folks in Butte City taken some obvious relevant factors into consideration, they might have opened a business with a better chance of success. If our gurusmitten Atlantans had thought about how bizarre the claim is that staring at the sun can bring clarity of thought, they might have saved their retinas. You may not have done anything quite so witless as the actions described in our examples. But everybody makes errors of judgment from time to time. The wise person is the one who wishes to keep such errors to a minimum and who knows how to do it. We hope this book helps make you a little wiser. One last thing before we move on. If you are reading this book for a course, chances are you will be expected to critique others’ ideas, and they will be asked to critique yours. Everyone understands the importance of screening one’s own ideas for defects and deficiencies (although we do not always do so), but many people draw a line when it comes to subjecting the views of others to scrutiny. Doing this is sometimes seen as a kind of personal attack. “Everyone is entitled to his or her opinion,” you often Attempting to debate with a person who has abandoned reason is like giving medicine to the dead. — UNIDENTIFIED E-MAILER ■ A rescue team in action. Bad luck—and bad judgment—can have grave consequences. moo86677_ch01_001-040.indd 4 6/17/08 10:31:17 AM