A Begginers Guide To Scientific Method

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A Beginner's Guide
to Scientific Method

A Beginner's Guide
to Scientific Method
Third E d ition

STEPHE N S . CAREY

Portland Community College

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Sclentfflc Method, Third
Stephen S. Carey

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Contents

PREFACE

VIII

ONE

SCIENCE
JustWhat Is Science?
AskingWhy

Scientific Method

The Consequences of Science
Scientific Method in Daily Life
Things to Come
Exercises

TWO

OBSERVATION
Making Accurate Observations
Anomalous Phenomena

Observation and Anomalous Phenomena

CONTENTS

The Burden of Proof
Summary
Exercises
THREE

21
22

PROPOSING EXPLANATIONS
Explanation
Causes

Correlation

31.

Causal Mechanisms

Underlying Processes
Laws

Function

T he Interdependence of Explanatory Methods
Rival Explanations and Ockham's Razor
Explanation and Description
Summary
Exercises
FOUR

44
44

TESTING EXPLANATIONS
The Basic Method

How to Test an Explanation

Testing Extraordinary Claims
Summary

FIVE

52
53

How Not to Test an Explanation

Exercises

64
64

ESTABLISHING CAUSAL LINKS
Causal Studies

Limited Effect Levels

Multiple Causal Factors
Bias and Expectation
Types of Causal Study

82
83

CONTENTS

Reading Between the Lines
Summary
Exercises
SIX

vii
89

91
92

FALLACIES IN THE NAME OF SCIENCE
What Is a Fallacy?
False Anomalies

107
109

Questionable Arguments by Elimination
Illicit Causal Inferences

Unsupported Analogies and Similarities
Untestable Explanations
Redundant Predictions
Ad Hoc Rescues

116

117
119

The Limits of Scientific Explanation

Exercises

125
126

FURTHER READING
INDEX

139

113

115

Science and Pseudoscience

Summary

111

137

124

107

Preface

his book is written for the student who has little or no background in

the sci �nces. Its aim is to provide a brief nontechnical introduction to
�

the basiC methods underlying all good scientific research. Though

use

this book as the main text in a college level critical thinking course about sci
ence and scientific method, it could easily be used as a supplement in any

course in which students are required to have some basic understanding of
how science is done.

Some will object to the very idea of a basic method underlying all the sci

ences, on the ground that there is probably nothing common to all good sci
ence other than being judged good science. While there is certainly something

to this objection, I think there are a few basic procedures to which instances
of good scientific research must adhere. If anything deserves to be called the
scientific method, it is the simple but profoundly fundamental process wherein
new ideas are put to the test-everything from the most rarefied and grand
theoretical constructs to the claims of the experimenter to have discovered
some new fact about the natural world.
Scientific method rests on the notion that every idea about the workings of

nature has consequences and that these consequences provide a basis for testing
the idea in question. How this insight is worked out in the world of science is
really all this book is about. No doubt, much good science is one step removed
from the proposing and testing of new ideas and this is the "something" to the
objection above. But whenever science attempts to understand how or why
things happen as they do, a basic, underlying methodology generally emerges

viii
j_

PREFACE

This is not to say that there is a step-by-step recipe which, if followed, will
invariably lead to a greater understanding of nature. If I have succeeded at only
one thing, I hope it is at showing the tentativeness v.rith which scientific results
are issued and the utter openness to revision that is essential to good science.
An essential part of an introduction to anything is an account of what it is
not. Hence, roughly a third of the text, in parts of Chapter 2 and 4 and espe
cially in Chapter 6, is about the antithesis of good science-bogus or pseudo
science. Inclusion of material on how not to do science is all the more impor
tant since, for the general student, much of the presumed "science" to which
he or she will be exposed v.rill be in the form of the rather extravagant claims
of the pseudoscientist. To confirm this, one need only turn to the astrology
column of any major newspaper or turn on one of the many television pro
grams that purport to provide an objective investigation of the paranormal.

You will find interspersed at strategic points, what I call quick reviews-brief

sununaries of material from chapter subse-ctions. Their purpose is to provide the
text with some breathing room but also to encourage the student to stop and
reflect on what they have read when they have completed an important topic.

EXERCIS E S
Students generally learn b y doing, not by talking about doing. Thus, every
important idea in the text is an idea with which the student is asked to grap
ple in solving the chapter exercises. Each chapter ends with a lengthy set of
exercises; they are the part of the book of which I am most proud and for
which I can claim some originality. I have tried to write exercises that are chal
lenging and fun to think about, require no special expertise, and yet illustrate
the extent to which scientific problem solving requires a great deal of creativ
ity. Many of the exercises come not from the world of official science but from
ordinary life. This illustrates a theme with which the book opens: Much of
what is involved in attempting to do science is thoroughgoing, hardworking
common sense, the very best instrument in solving many of the problems of
our day-to-day lives.
Many of the exercises are written in a manner that requires the student to
work with a number of key ideas all at once. At the end of Chapter 4, for
example, the student is asked to solve problems involving all of the ideas dis
cussed in the chapter and a few from earlier chapters as well. The exercises in

Chapter 6 rely on ideas from throughout the book. My preference is to intro
duce students straightaway to the fact that most interesting problems involve a
complex of problematic issues, and that problem solving begins with two
essential steps: (1) getting a good overall sense of the problem or problems, and
(2) only then beginning to break its solution down into a series of discrete bits
of critical work.

Exercises in Chapter 4 and Chapter 5 require the student to design some

sort of experiment. I have found these exercises particularly useful in encour-

PREFACE

aging students to think both creatively and critically. I assign different problems
to small groups of students as homework to be done as a group. The home
work results of each group are then exchanged with another group who must
criticize the design submitted by the first group. In class, designers and criti
cizers meet and refine each of the two experiments on which they have been
working. My role in the process is largely to keep the troops calm and to medi
ate any potentially explosive disputes

N E W TO T H E T H IR D E D I T I O N
New to the thtrd edition i s a chapter devoted to observation-chapter 2. The
material on explanations has been divided between two shorter chapters, and
extraordinary claims are now covered in Chapter 2 and Chapter 4 rather than
in a chapter of their own. The chapter on fallacious applications of scientific
method-now Chapter 6-has been reorganized and simplified. Several other
minor changes will, I hope, make the ideas presented more accessible to stu
dents. A more explicit definition of science and of scientific method is given in
Chapter 1, and the latter now provides the basis for the order in which major
ideas are covered in the ensuing chapters: observing, proposing, and testing
new explanations. The material on designing decisive experimental tests in
Chapter 4 is simplified; much of the jargon of older editions is gone, and the
very idea of a good test is discussed in something close to ordinary language.
Every exercise set has been refined and all contain at least a few new prob
lems. New exercise sets have been added in Chapter 2 and Chapter 5. A few
exercise sets have been shortened to keep the overall number of exercises about
the same as in earlier editions.

ACKNOWLEDGMENTS
Having taken much credit for some innovation in the writing o f the chapter
exercises, I can claim, on the other hand, little originality for much of the
expository material, particularly in the first three chapters of this book. The
case study at the center of Chapter 1 will reveal, to those familiar with the phi
losophy of science, my indebtedness to the work of Carl Hempel, particularly
his classic introductory text,

Philosophy of Natural Sdence. The central approach
and organization of Chapter 5 owes much to Ronald Giere's excellent text,
Understanding Sdentific Reasoning. I have also had the good fortune to receive

the advice of several readers of earlier versions of my manuscript, including
Davis Baird, University of South Carolina; Stanley Baronett and Todd Jones,
University of Nevada, Las Vegas; Brad Dowden, California State University,
Sacramento; Jim Kalat, North Carolina State University; and Bonnie Paller,
California State University, Northridge. Special thanks to the reviewers of the

PREFACE

first, second, and third editions, David Conway, University of Missouri,
St. Louis; George Gale, University of Missouri, Kansas City; Judy Obaza, King's
College; June Ross, Western Washington University; LaVonne Batalden, Colby
Sawyer College; Blinda E. McClelland, University of Texas at Austin; Benjamin
B. Steele, Colby-Sawyer College; and Jayne Tristan, University of North Car
olina. Nearly every change in the second and third edition was motivated by
their advice and suggestions.
One final note. Though my field is philosophy, you will find conspicuously
missing any emphasis on central topics in the philosophy of science. There is,
for example, no explicit discussion of the hypothetical-deductive method, of
the covering law model of explanation, nor of their attendant difficulties, of the
rather more notorious problems in the theory of confirmation, nor of the
infighting between realists and antirealists. My hunch (which is considerably
beneath a firm belief) is that an introduction to anything should avoid philo
sophical contemplation about the foundations of that thing, lest it lose focus, if
not its course, in the sight of its audience. Once the thing in question is fully
absorbed and understood, then and only then is it time for philosophical con
templation of its deep commitments. Though I have not altogether avoided
topics dear to the philosopher of science, I discuss them briefly and, for the
most part, in a jargon-free fashion. My hope is that I have not purchased econ
omy and readability at the expense of either accuracy or a sense of wonder
about the philosophical issues embedded in the methods by which science is
conducted.

Stephen S. Carey

Science
Science when well digested is nothing
but good sense and reason.

STANISLAUS

J U S T W H AT I S S C I E N C E?

e all have a passing familiarity with the world of science. Rarely

does a week go by wherein a new scientific study or discovery is

not reported in the media. "Astronomers confirm space structure

that's mind-boggling in its immensity," and "Scientists identify gene tied to
alcoholism," are the headlines from two recent stories in my daily newspaper.

Another opened with the following: "A panel of top scientists has dismissed
claims that radiation from electric power lines causes cancer, reproductive dis
ease, and behavioral health problems." Yet m.tny of us would be hard pressed
to say much more about the nature of science than that science is whatever it
is scientists do for a living. Hardly an illuminating account!

So, what more might we say in response to the question, '1ust what is sci

ence?"We cannot hope to answer this question by looking at the subject mat
ter of the sciences. Science investigates natural phenomena of every conceiv

able sort-from the physical to the biological to the social. Scientists study
everything from events occurring at the time of the formation of the universe
to the stages of human intellectual and emotional development to the migra
tory patterns of butterflies. Though in what follows we will often refer to

"nature"

"the natural world" as that which science investigates, we must

understand that the "world" of the scientist includes much more than our
planet and its inhabitants. Judging by its subject matter, then, science is the
study of very nearly everything.

CHAPTER ONE

Nor can we hope to answer our question by looking at the range of activ
ities in which scientists engage. Scientists theorize about things, organize vast
research projects, build equipment, dig up relics, take polls, and run experi
ments on everything from people to protons to plants. A description of science
in terms of the sorts of things scientists typically do, then, is not going to tell
us much about the nature of science, for there does not seem to be anything
scientists typically do.
If we are to understand just what science is, we must look at science from
a different perspective.We must ask ourselves, first, why scientists study the nat
ural world, and, then we must look at the way in which scientific enquiry is
conducted, no matter what its subject.

ASKING WHY
O f course, w e cannot hope t o give a simple, ubiquitous reason why each and
every scientist studies the natural world. There are bound to be as many rea
sons as there are practicing scientists. Nevertheless, there is a single "why"
underlying all scientific research. In general, scientists study the natural world
to figure out why things happen as they do. We all know, for example, that the
moon is riddled with craters. From a scientific point of view, what is of real
interest is precisely why this should b e so. What natural processes have led to
the formation of the craters? At the most basic level, then, science can be
defined by reference to this interest in figuring things out. So, an essential part

of the answer to our question. ''Just what is science?" involves the basic aim of

science. Science is that activity, the underlying aim of which is to further our under
standing of why things happen as they do in the natural world. To see what it is that
scientists do in attempting to "make sense" of nature, let's take a look at an his
torical instance that, as it turns out, played an important role in the develop
ment of modern medicine.
Up until the middle of the nineteenth century, little was known about the
nature of infectious diseases and the ways in which they are transmitted. In the
mid-eighteen hundreds, however, an important clue emerged from the work
of a Viennese doctor, Ignaz Semmelweis. At the time, many pregnant women
who entered Vienna General Hospital died shordy after having given birth.
Their deaths were attributed to something called "childbed fever." Curiously,
the death rate from childbed fever in the hospital ward where the patients were
treated by physicians was five time higher than in another ward where women
were seen only by midwives. Physicians were at a loss to explain why this
should be so. But then something remarkable occurred. One of Semmelweis's
colleagues cut his finger on a scalpel that had been used during an autopsy.
W ithin days, the colleague exhibited symptoms remarkably like those associ
ated with childbed fever and shordy thereafter died. Semmelweis knew that
physicians often spent time with students in the autopsy room prior to visiting
their patients in the maternity ward.

SCIENCE

Thanks largely to the clue provided by the death of his colleague, Sem
melweis speculated that something like the following might be responsible for
the glaring differences in death rates in the two wards. Childbed fever was
caused by something that physicians came into contact with in the autopsy
room and then inadvertently transmitted to pregnant women during the
course of their rounds in the maternity ward. Serrunelweis appropriately
termed this something, "cadaveric matter."
The challenge faced by Serrunelweis was to devise a way of testing his ideas
about the link between cadaveric matter and childbed fever. Semmelweis rea
soned as follows: If childbed fever is caused by cadaveric matter transmitted

from physician to patient, and if something were done to eradicate all traces of
cadaveric matter from the physicians prior to their visiting patients in the
maternity ward, then the incidence of childbed fever should diminish. In fact,
Semmelweis arranged for physicians to wash their hands and arms in chlori
nated lime water-a powerful cleansing agent-prior to their rounds in the
maternity ward. Within two years, the death rate from childbed fever in the
ward attended by physicians approached that of the ward attended by mid
wives. By 1848, Serrunelweis was losing not a single women to childbed fever!

S C I E NT I F I C M E T H O D
A t its most basic level, scientific method i s a simple, three-step process by
which scientists investigate nature. Begin by carefully observing some aspect of
nature. If something emerges that is not well understood, speculate about its
explanation and then find some way to test those speculations. Each step
observing, explaining, and testing--is nicely illustrated by the historical event
we have just described.

Observing
Before we can begin to think about the explanation for something we must
make sure we have a dear sense of the facts surrounding the phenomenon we
are investigating. Semmelweis's explanation of childbed fever was prompted by
a number of facts, each the product of c.areful observation: First, the fact that
the rates of childbed fever differed in the wards in question; second, that
patients in the ward where the rate was the highest were treated by physicians,
not midwives; and finally the remarkable symptoms of his dying colleague.
Getting at the facts can both help us to establish the need for a new expla
nation and provide clues as to what it might involve. Suppose, for example, that
careful long-term observation revealed to Semmelweis that on average the
death rates were about the same in the two wards. In some months or years the
rate was higher in one ward, in others, higher in the other. In these circum

stances nothing puzzling needs to be accounted for-the original set of obser

vations would seem to be nothing more than the sort of brief statistical fluc

tuation that is bound to occur now and then in any long series of events. But

CHAPTER ONE

as Semmelweis found, the difference in death rates was not a momentary aber
ration. Thus, by careful observation Semmelweis was able to establish that
something not fully understood was going on. It was Semmelweis's good for
tune to then make the key observation that suggested what might be respon
sible for the problem-the unusual similarity between the symptoms of the
dying mothers and his sick colleague.

Proposing Explanations

To explain something is to introduce a set of factors that account for how or why

the thing in question has come to be the case. Why, for example, does the sun

rise and set daily? The explanation is that the earth rotates about its axis every

twenty-four hours.When something is not well understood, its explanation will
be unclear. Hence the first step in trying to make sense of a puzzling set of facts

is to propose what we might call an explanatory story-a set of conjectures that
would, if true, account for the puzzle. And this is precisely what Senunelweis set
about doing. Semmelweis's explanatory story involved the claims that something

in cadaveric matter causes childbed fever and that this something can be trans
mitted from cadaver to physician to patient by simple bodily contact.
Semmelweis's explanation

was

all the more interesting because it intro

duced notions that were at the time themselves quite new and puzzling---s ome
very new and controversial ideas about the way in which disease is transmit
ted. Many of Semmelweis's contemporaries, for example, believed that
childbed fever

was

the result of an epidemic, like the black plague, that some

how infected only pregnant women. Others suspected that dietary problems or
difficulties in the general care of the women were to blame. Thus, in propos
ing his explanation, Semmelweis hinted at the existence of a new set of
explanatory factors that challenged the best explanations of the day, and which
had the potential to challenge prevailing views about how diseases are spread.

All that remained for Semmelweis was to find a way to test his explanation.
Testing Explanations

How can we determine whether a proposed explanation is correct or mis
taken? By the following strategy. First, we look for a consequence of the expla
nation--something that ought to occur, if circumstances are properly arranged
and if the explanation is on the right track. Then we carry out an experiment
designed to determine whether the predicted result actually will occur under
these circumstances. If we get the results we have predicted, we have good rea
son to believe our explanation is right. If we fail to get them, we have some
initial reason to suspect we may be wrong or, at the very least, that we may
need to modify the proposed explanation.

This was precisely the strategy Semmelweis employed in testing his ideas
about the cause of childbed fever. If something physicians have come into con
tact with prior to entering the maternity ward is causing the problem and if
this "something" is eradicated, then it follows that the rate of childbed fever
should drop. And, indeed, once these circumstances were arranged, the out-

SCIENCE

come predicted by Semmel weis occurred. As a result, he was confident that his

initial hunch was on the right track. By contrast, had there been no reduction

in the rate of childbed fever as a result of the experiment, Semmelweis would
at least have had a strong indication that his hunch was mistaken.
At the most basic level, the scientific method is nothing more than the sim
ple three-step process we have just illustrated--carefully observing some aspect
of nature, proposing and then testing possible explanations for those observa
tional findings that are not well understood. In the chapters to follow we

will

need to add a great deal of detail to our initial sketch of scientific method. We

will come to recognize that scientific method is not all that straightforward nor,

for that matter, easy to apply. Explanations are not always as readily tested as our

initial examples might suggest nor are test results always as decisive as we might

like them to be. We will also find that, with some minor variations, scientific

method can be used to test interesting and controversial claims as well as expla
nations. For now, however, we can use what we have discovered about scientific
method to get at the remainder of the answer to our opening question.

Just what is science? Science is that activity, the underlying aim of which is tofur
ther our understanding of why things happen as they do in the natural world.It aa:om
plishes thisgoal by applications ifscientific method-the process ifobserving nature, iso
lating a facet that is not well understood, .and then proposing and testing possible
explanations.

T H E C O N S E Q U E N C E S Of S C I E N C E
Before moving on, an important caveat is i n order. I n focusing o n the preoc
cupation of science with making sense of nature-of providing and testing
explanations-we have ignored what is surely an equally compelling interest of
the sciences, namely, making the world a better place to live via technological
innovation. Indeed, when we think of science, we often think of it in terms of
some of its more spectacular applications: computers, high speed trains and jets,
nuclear reactors, microwave ovens, new vaccines, etc. Yet, our account of what

is involved in science is principally an account of science at the theoretical

level, not at the level of application to technological problems.

Don't be misled by our use of the term "theoretical" here. Theories

are

often thought of as little more than guesses or hunches about things. In this
sense, if

have a theory about something, we have at most a kind ofbaseless

conjecture about the thing. In science, however, "theory" has a related though
different meaning. Scientific theories may be tentative, and at a certain point
in their development will involve a fair amount of guesswork. But what makes
a scientific theory a theory is its ability to explain, not the fact that at some
point in its development it may contain some rather questionable notions.

Much as there will be tentative, even imprecise, explanations in science, so also

will there be secure, well established explanations. Thus, when we distinguish
between theory and application in science

are contrasting two essential

concerns of science: concern with understanding nature, and concern with

CHAPTER ONE

exploiting that theoretical understanding as a means of solving rather more
practical, technological problems.
Yet there is an important, if by now obvious, connection between the worlds
of theoretical and applied science. With very few exceptions, technical innova
tion springs from theoretical understanding. The scientists who designed, built,
and tested the first nuclear reactors, for example, depended heavily on a great
deal of prior theoretical and experimental work on the structure of the atom
and the ways in which atoms of various sorts interact. Similarly, as the case we
have been discussing should serve to remind us, simple but effective new pro
cedures for preventing the spread of disease were possible only after the theo
retical work of Semmelweis and others began to yield some basic insight into
the nature of germs and the ways in which diseases are spread.

S C I E N T I F I C M E T H O D I N D A I LY L I F E
The brief sketch o f scientific method given above may have a familiar ring to
it and for good reason. To a large extent thinking about things from a scientific
perspective--thinking about the "haws" and "whys" of things-involves noth

ing more than the kind of problem solving we do in our daily lives.

To see this, imagine the following case. For the last few nights, you haven't
been sleeping well. You've had a hard time getting to sleep and have begun
waking up frequendy during the course of the night. This is unusual, for you
are normally a sound sleeper. What could be causing the problem? Well, next
week is final exam week and you have been staying up late every evening,
studying. Could concern about your upcoming exams be causing the prob
lem? This seems unlikely, since you have been through exam week several
times before and have had no problems sleeping. Is there anything else unusual
about your behavior in the last few nights? It has been quite warm, so you
have been consuming large quantities of your favorite drink, iced tea, while
studying. And this could explain the problem. For you are well aware that
most teas contain a stimulant, cafe
f ine. It may well be the cafe
f ine in your iced
tea that is disturbing your sleep! But is this the right explanation? Here, a rel
atively quick, easy, and effective test can be performed. You might, for exam
ple, try drinking ice water instead of iced tea in the evening. If you were to
do this, and if you again began sleeping normally, we would have good rea
son to think that our explanation was right; it must be the caffeine in the iced
tea. Moreover, if you were not to begin sleeping normally we would have
some reason to suspect that we have not yet found the right explanation; elim
inating the caffeine didn't seem to do the trick.
T hough nothing of any great scientific consequence turns on the solution
of our little puzzle, the solution nevertheless is a straightforward application of
scientific method: observing something unusual, venturing a guess as to what
its explanation might be, and then finding a way to test that guess.

_j_

T H I N G S TO C O M E
I n the chapters t o follow, our central concern with b e t o expand the prelimi
nary sketch of scientific method given so far. Along the way, we will pay par
ticular attention to the pitfalls scientists are likely to encounter in making accu
rate observations and in designing and carrying out decisive experimental tests.
On our agenda

will be a number of controversial topics, perhaps none more so

than the distinction between legitimate and fraudulent applications of scien
tific method. Nothing can do more to lend an air of credibility to a claim than
the suggestion that it has been "proven in scientific studies" or that it is "backed

by scientific evidence." A sad fact, however, is that many claims made in the
name of science

are

founded on gross misapplications of some aspect of scien

tific method. Indeed, so numerous are the ways in which scientific method can
be abused that we will find it necessary to devote a chapter to fallacies com
monly committed under the guise of scientific research.
Our goals, then, in the chapters to follow are twofold. Our first and most
important goal is to become familiar with the basic methodology common to
all good scientific research. Our second goal is to learn to distinguish between
legitimate and bogus applications of scientific method. Having accomplished
these goals, I think you will find yourself quite capable of thinking clearly and
critically about the claims of scientists and charlatans alike to have advanced
our understanding of the world about us.

E X ER C I S E S

Try your hand a t telling explanatory
stories. Thefollowing exercises all describe
curious things. See ifyou can come r1p with
one or two explanationsfor each. Keep
in mind, your explanation need not be
trne but it must be such that it would
explain the phenomena in question,
if it were true.
1.

A survey done recently revealed
that whereas 10 percent of all
20-year-olds are left-handed,
only about 2 percent of all

Americans have a serious weight
problem. In the last decade, both
the number of Americans who
are overweight and who are
clinically obese has increased by
more than 10 percent. The in
crease over the last two decades
in both is nearly 20 percent.

W hy have so many Americans
switched from
sedans to
sports utility vehicles and trucks
in the last few years?

driving

Have you ever noticed that
baseball players tend to be quite
superstitious? Batters and pitch
ers alike often run through a

We all know what happens when
depress the handle on a toilet.
The flapper inside the tank
opens and water rushes into the
bowl, flushing it out and refilling

series of quite bizarre gestures
before every pitch.

the bowl. But what keeps the
fresh water in the bowl?

75-year-olds are left-handed.

Observation

M A KING A C C UR A T E O B S ERVATIO N S

uppose you were t o pause for a few minutes and try t o list all o f the
objects in your immediate vicinity. You v:ould quickly realize that the
task of making a set of accurate observattons can be a tricky business.

In this case, one problem stems from the fact that it is not all that clear what
qualifies as an object nor, for that matter, what it is to be in the immediate
vicinity. The book you are reading is undoubtedly an object. But what of

the bookmark stuck between its pages? No doubt the picture on the wall
qualifies. But what of the nail on which it is hanging? And how should we
fix the limits of the immediate vicinity? Do we mean by this the room in
which you are sitting? Everything within a 10-foot circumference of you?
Everything within reaching distance? Even after we have settled on work
ing definitions for these key terms, we face an additional problem. Doubt
less you are likely to miss a few things on your first visual sweep. So we need
to find some way to guarantee that we have included everything that fits in
our two categories.
In general, the process of making a set of observations must be sensitive to
a number of concerns, two of which are illustrated in the case above.

1. Do we have a clear sense of what the relevant phenomena are?
2. Have we found a way to insure we have not overlooked anything in the

process of making our observations?

OBSERVATION

These two questions can usually be addressed in a fairly straightforward
way. Some careful thinking about just how key terms are to be applied will set
tle the first. Keeping a written record of our results will satisfY the second. In
the example above, one simple way to accomplish this would be to make a list
of the objects found in a first set of observations and then add in overlooked
items from a second set. Another would be to ask someone else to check your

results. The need for a written record is all the more crucial because of the nat
ural temptation to think we can do without one.Try, for example, to think how

many times today you have done something commonplace like, say, sitting
down or opening your wallet or saying "hello." Recollection will undoubtedly
turn up a number ofinstances. But our memories are fallible and we are likely
to miss something no matter how confident we are that we have remembered
all the relevant cases. The solution is simply to keep some sort of written tally.

Observations are not always undertaken with a clear sense of what data may

be relevant. Think, for example, of a detective at the scene of a crime. What small
details need to be noted or perhaps preserved for future reference? Moreover, a
set of observations may yield unanticipated information--data that does not
conform to the observer's sense of what is relevant---but information that is

nonetheless of some importance. Recently, medical researchers at a large univer
sity were studying the efe
f ct of calcium on pregnancy-related high blood pres
sure.Though they observed no significant reductions in the blood pressure of the
women in their study who took calcium, they did notice something quite inter
esting and unexpected. The women in their study who took calcium during
pregnancy had lower rates ofdepression than those who took a placebo instead
of calcium. As a result, the researchers began an entirely new study, one designed

to determine the extent to which calcium can prevent depression in pregnant

women. As this example suggests, it is important not to become too attached to

fixed notions of what may constitute relevant observational data. Otherwise, we
run the risk of missing something that may turn out to be significant.

Often in science, a set of observations will be prompted by the need to
learn more about something that is not well understood. Not too long ago, for
example, researchers uncovered what seemed to be a curious fact. On average,
right-handed people live longer than left-handed people.1 To begin to under
stand why this is the case we would need to search carefully for factors that
affect only the left-handed (or right-handed), and which might account for the
different mortality rates of the two groups. When, as in this case, observations
involve phenomena that are not well understood, three additional concerns
may need to be addressed.
3. What do we know for sure? "What is based on fact and what on conjecture
or assumption?
4. Have we considered any necessary comparative information?
5. Have our observations been contaminated by expectation or belief?
Rarely will the answers to these questions come easily or quickly. Consider
what may be involved in dealing with each.

CHAPTER TWO

We observe things every day that we
scarcely notice. How many of the
following questions can you answer?
Un which direction do revolving
doors turn?

2. When you walk, do your arms

swing with or against the rhythm
of your legs?
3. What are the five colo� on a
Campbell's soup label?
4.ln which direction do pieces travel
around a Monopoly board,
clockwise or counterclockwise?
5. On the American flag, is the
uppermost stripe red or white?

6.1n Grant Wood's painting
uAmerican Gothic." is the man to
the viewer's left or right?
7.In which hand does the Statue of
liberty hold her torch?
8. Which side of a woman's blouse
has the buttonholes on it-from
her view?
9. How many sides are there on a
standard penci l?
10.0n most traffic lights, is the green
light on the top or the bottom?
Answers are given at the end of
the chapter.

J.1!hat do we know for sure? Hlhat is based on fact and what on conjecture or assump
tion? Have you ever noticed that the full moon often appears appreciably
larger when it is near the horizon? As you read this you are probably picturing
a large, yellow-orangish moon in your mind's eye.You've probably also heard
others comment on this phenomenon. But appearances can be deceiving,
opinions wrong. In fact the moon is not appreciably larger when near the hori
zon. This can be determined by a simple set of observations. The next time the
moon seems unusually large, stretch your arm as far as it will go and use your
thumb to measure the moon's diameter. Make a note of how big it seems and

then make a similar measurement when the moon is overhead and apparently
much smaller. You will find that its diameter is about the same in both cases.
What makes the moon appear larger in the former case is its close proximity
to other objects near the horizon. When we judge the size of the moon by ref

erence to other objects--o bjects not near the moon when it is overhead-we
mistakenly conclude that its image is larger.

As this example illustrates, it is always worthwhile to pause and think about

any assumptions we may be making about the phenomenon under investiga

tion. Don't let unwarranted assumption masquerade as fact. Always ask: What

do I really know about the phenomenon under investigation and what am I
assuming based on what I have been told or have heard, read, etc.? The answer

to this question may point you in the direction of observations you will need
to make to test whatever assumptions you have unearthed.
Jim Hightower, a well known political writer, recalls that as a child he was
told by his grandfather that raccoons always wash their food because they do
not have salivary glands. But after spending an early morning observing a fam
ily of raccoons he quickly carne to realize that what his grandfather had told
him-what he assumed to be true-was in error. The raccoons didn't wash the

food he left for them before eating it, and appeared to be salivating. M it turns

out raccoons do have salivary glands. Often, it seems, we can sort fact from fic

tion simply by taking time to look and see what is going on rather than implic
idy trusting whatever assumptions we may bring to the investigation.

Have we considered any necessary comparative information?

Many people claim that

strange things happen when the moon is full. One interesting and curious
claim is that more babies are born on days when the moon is full or nearly full
than during any other time of the month. What obser vations would we need
to make to determine whether there is anything to this claim? Certainly we
would want to look at the data pertaining to the number of births when the
moon is full. But this is only part of the story. We would also need to look at

the numbers for other times, times when the moon is not full. If the birth rate

is not appreciably higher when the moon is full, then there is litde remarkable
about the claim at issue. Lots of births occur when the moon is full. But then
lots of births occur during all phases of the moon. Indeed, careful studies done
at a number of hospitals reveal that there is nothing unusual about the birth
rate when the moon is full. When birth rates were examined over the period
of a year or two, it turned out that, on average, there were no more or less
births during the period near a full moon than during any other period. In a

given month, there might be a few more (or less) births near a full moon than
during other parts of the month, but when averaged out over a long period of
time, the difference disappears.
You've probably heard that apparently infertile couples who adopt a child
frequently go on to give birth to a child. Is there some connection between the
two events? To get at the answer to this question, we need comparative data.
How, generally, do such couples fare when compared with another group of
couples-those who are diagnosed as being infertile but choose not to adopt?
01/e might also want to look at what happens to fertile couples who do and do
not adopt as well.) As it turns out, pregnancy rates for apparendy infertile cou
ples who do not adopt are about the same as for similar couples who adopt.
As these examples suggest, part of the point of making a set of observations
is to determine what, if anything, is unusual about the data collected. Remem
ber, the business of science is understanding. Thus, it is crucial to determine
whether a set of observations present us with something that is not well under

stood. As we have seen, there is nothing out of the ordinary about the number

of births when the moon is full nor about the pregnancy rates of infertile cou
ples; in neither case have we uncovered anything that requires explanation. The

process of making observations should always be undertaken with an eye to
figuring out whether the results square with what is currendy known. And this
often involves hunting for the right sort of comparative data--data that will
enable us to decide the extent to which our observations have led us to some
thing that really does need explaining.

Have our observations been contaminated by expectation or beliif?

Our experiences

are colored by our beliefs and expectations. When I hear a chirping sound on

CHAPTER TWO

the ledge outside my office, I assume that what I am hearing is a bird, largely
because of prior experiences, the belie& formulated on the basis of those expe
riences, and other relevant background beliefs. In the past when I have heard
chirping outside my window I have looked out and observed a jay or a robin.
And so I make the easy and entirely unproblematic inference that I am now
hearing a robin or a jay though, strictly speaking, what I am hearing is only a
noise that sounds to me like chirping.
The extent to which beliefs can influence our experiences is powerfully
illustrated in the following example. Read the passage below and before read

ing on, pause and try to figure out what it is about.

With hocked gems financing him, our hero bravely defied all scornful
laughter that tried to prevent his scheme. "Your eyes deceive," he had said.
''An egg, not a table correcdy typiftes this unexplored planet." Now three
sturdy sisters sought proof. Forging along, sometimes through calm
vastness, yet more often very turbulent peaks and valleys, days became
weeks as many doubters spread fearful rumors about the edge. At last from
nowhere welcome winged creatures appeared, signifying momentous

If you are like me, you found this passage hard to decipher and would find
it equally difficult to give a rough paraphrase of what it says. In fact, this story
is about Columbus's voyage to the Americas. Reread the passage in light of this
new information and note how much sense it makes. Obviously, nothing in the
passage has changed. What has altered your experience of reading the passage
is a new belief about it.
Normally, we do not need to be too concerned with the influence exerted
by expectation and belief over our experience. Many, perhaps most of our
beliefS are well founded and our expectations usually reliable. Nonetheless, it is
important to be aware of the extent to which our observations can be influ
enced by belief and expectation. The point of making a set of scientific obser
vations is to come up with an objective record of what is going on, often in cir
cumstances where we are really not sure. When experience is processed through
the filter of belief and expectation, distortion can creep into our account of
what we are observing, particularly when we have strong convictions about
how things are going to turn out. Several years ago, for example, some people
claimed that the word "sex" could be discerned in a puff of smoke in a brief
sequence from theWalt Disney film, The Lion King. I have shown the sequence
to hundreds of students. Most of those who have not heard that "sex" is in the
puff of smoke simply do not see it. However, once they are told what to look
for, many people can see the word though many still do not. Seeing is believ
ing, but in this case it seems what one believes can determine what one sees!
Trained scientists are not immune to the influence of expectation and
belief on observation. In 1877 and 1881, the Italian astronomer, Giovanni

Schiaparelli, turned his telescope to Mars, which was unusually close to earth.

Schiaparelli claimed that he had observed

canali

on the surface of the planet.

Reports of this event in the English-speaking media translated the Italian canali

as "canals" though the word means both "canals" and "channels," the latter
meaning being intended by Schiaparelli. Schiaparelli had observed straight lines
arranged in a complex fashion but which he did not take to be unequivocal
evidence of intelligent beings on Mars. A number of astronomers, among them
the American Percival Lowell, claimed also to see Martian "canals," some going
so far as to draw detailed maps of them. (At the time, astronomical photogra
phy

was

not sufficiently developed to allow for pictures of Mars. The "canals"

were observed visually, a fact that allowed for a good deal of leeway in inter
preting what was observed.) Of course, there are no canals on Mars. Those
astronomers who believed that they were seeing canals were victims of the
influence belief can exert over observation.
An even more remarkable example ofthe extent to which belief can influ
ence scientific observation involves a long since discredited phenomenon,
N-rays. Several years after the discovery of X-rays in the late 1800s, a highly
respected French physicist, Rene Blondlot, announced that he had detected a
subde new form of radiation, N-rays, named after the University of Nancy,
where he was a professor. The evidence for the new form of radiation was
provided by changes in the intensity of a spark when jumping a gap between
two wires running from a cathode ray tube, the forerunner of the modern TV
tube. In subsequent experiments, Blondlot discovered that the effects of N
rays were the most pronounced for very weak and short sparks and that they
could be refracted by a prism, something not true ofX-rays. The problem was
that other experimenters had mixed results in trying to replicate Blondlot's
experiments. Somt: confirmed his findings, others had no luck. One
researcher, Augu�te Charpentier, claimed to have evidence that N-rays are
emitted by people and animals. The main problem faced by researchers was
that the effects of N-rays were quite subtle, involvi ng only slight variations in
light intensity. Some critics claimed that the effects could be attributed to the
way the human eye reacts to faint light sources. Against his critics, Blondlot
and his colleagues insisted they had demonstrated the existence of a new form
of radiation, even going so far as to suggest that people not properly trained
to observe N-rays would have difficulty detecting them. Matters came to a
head in 1905 when an American physicist, Robert Wood, came to Nancy to
observe Blondlot's work. One crucial experiment was intended to demon
strate the deflection of N-rays by a prism. Wood asked Blondlot to repeat the
experiment but, unbeknownst to Blondlot, removed the prism from the appa
ratus. Blondlot claimed to obtain the same quantitative measurements of N
ray deflection by the prism even when the prism was missing! Wood published
the results of his investigations and within a few years, N-ray research had
come to an end. The researchers who for several years provided experimental
backing for Blondlot's new phenomenon had simply allowed belief and
expectation to contaminate their findings.
The cases we have considered in this section suggest that it is always worth
while to step back from a set of observations and gain some much needed crit

JVhat am I actually seeing, hearing, etc.,
and what am I bringing to my observation via thefilter l>Omewhat obscure:

"What can be done with fewer is done in vain with more." A more appro
priate version of this principle for our purposes is the following: given com
peting explanations, any of which would, if true, explain a given puzzle, we

should initially opt for the explanation which itself contains the least num

ber of puzzling notions. The rationale behind this admonition should be

clear. If a puzzle can be explained without introducing any additional puz
zling notions, there is no good reason to entertain any explanation that
involves additional puzzles.
By comparison with our two bizarre explanations, our first �lanation
that you have put your keys somewhere you haven't looked yet-fits the bill
here. So, to say that one of a series of rival explanations is the most plausible
is to say it is the one most in keeping with Ockham's Razor. Keep in mind
that Ockham's Razor does not rule out explanations which themselves
involve notions not fully understood. Rather it only suggests tl'lat given com
peting explanations, we should favor the one which involves tthe least num
ber of problematic notions. Forced to choose between cleve-r burglars and
black holes to account for the missing keys, Ockham's Razor would suggest
the former

PROPOSING EXPLANATIONS

E X P L A N AT I O N A N D D E S C R I P T I O N
I n this and the last chapter we have discussed two key elements o f scientific
method: observation and explanation. Unfortunately, many reports of extraor
dinary happenings of the sort discussed in Chapter 2 blur the distinction
between these two key notions. Ideally, observations should be couched in
purely descriptive language, language that tells us what occurred-no more, no
less. But often reports of extraordinary events contain a good deal that is not
purely descriptive. Imagine, for example, someone were to report awakening in
the middle of the night to discover what appeared to be their long-departed
grandmother standing at the foot of the bed. They might subsequently claim:
(1) I saw the ghost ofmy dead grandmother.
But what, precisely, is factual in (l)?What, that is, can we be confident actu

ally happened? That the person had an extraordinary experience is clear.
Beyond this it is hard to know just what to say. Consider two rival accounts of
what may have happened:
(2) X had a vivid life-like dream in which X's grandmother appeared.

(3) Somebody played an elaborate but vicious prank on X in the middle of
the night.

(1) through (3) implicitly contain explanations of the event in question. That
is to say, each presupposes the truth of a very different explanation: (1) that what
the person actually saw was a ghost; (2) that what he or she "saw" was part of a
dream; and (3) that what was seen was real, but a hoax, not a ghost.
Similarly, many anecdotal reports of the extraordinary contain much more
than a simple, objective description of the experience. Such reports often blend
fact with untested explanation and are what we might call

explanation laden.

For

example,"The flying saucer hovered over the horizon and then accelerated away

at a fantastic rate," tells us a couple of things about a person who might claim to
have witnessed such an event. First, the person had an undeniably extraordinary
experience. Second, the person believes the proper explanation for the experi
ence is that he or she actually saw an intelligently controlled spacecraft.
In evaluating such a report, we must do our best to separate the descriptive
wheat from the explanatory chaff. If we are able to subtract out the explanation
laden portions ofa report of the extraordinary, we may be able to arrive at a dear
sense of what actually

was

experienced and, thus, what needs to be explained.

Think once again of our flying saucer report. Suppose we could establish, for
example, that the person making the report actually saw a bright light near the

horizon, looked away to call to a friend, looked again and saw only a dim, twin
kling light at some distance from the original light. Having gotten dear on this

much, we would at least be in a position to think about rival explanations more
plausible that the one implicit in the initial description of the event.

I once spoke with a person who claimed to have lived in a haunted house.

He recalled that every few nights he would hear a knocking at the front door

CHAPTER THREE

despite the fact that there was never anyone there when he opened it.We agreed
that a more accurate description of the experience would contain only the
salient facts: on several occasion he heard a series of sounds, very much like
knocking at the door, and the sounds seemed to come from the area of the house
near the front door. He also added that he was never near the door when he
heard the noise. Once we focused on this new, more objective description, sev
eral plausible explanations inunediately came to mind; a tree or bush knocking
against the house or perhaps wme activity outside or even inside that sounded,
from a distance, like knocking. Now, we may never discover what really hap
pened on those nights when the person in this episode heard a " knocking" at

the door. At the very least, however, we know what parts of the story are fact,

what parts speculation. And this is the real value of carefully distinguishing
between the descriptive and explanatory elements of an extraordinary claim.

S U M M ARY

An explanation, in science, is an account ofhow or why something has come to

be the case. Both theories and hypotheses involve explanations. Theories tend to
be broad, unifYing explanations while hypotheses are more limited in scope. Both
can be tentative or well confirmed. Scientific explanations can make reference to
causes, causal mechanisms, underlying processes, laws or function, all ofwhich are
suii1l11le
lri2 d in the Quick Review on p. 39. Explanations often leave some
explanatory questions about the phenomenon in question unanswered. To enrich
an explanation of one type, other types of explanation may need to be given.
Correlations alone explain very little unless they are accompanied by evidence
that the correlated terms are either direcdy or indirecdy linked.
Competing explanations for a single set of facts can be evaluated by the use
of Ockham's Razor---a principle to the effect that among rival explanations,
the one containing the least number of puzzling notions is most likely to be
true. Many apparendy descriptive claims contain explanatory elements. In such
cases, it will be necessary to isolate the descriptive elements in order to begin
thinking about possible explanations.

EXERCISES

Exercises 1� 15 involve explanations of
one sort or other. For each exercise, answer
thefollowing questions:
1.

What is being explained?
What is the explanation?
What, ifany, recognizable sorts of
explanatory claims occur in the
explanation?

Your choices are: causes, causal
mechanisms, laws, underlying
processes, orfunction. Some of the
exercises may involve more than one
sort ofexplanation.
(Note: On page 50 a solution is provided
for Exercise 1.)
1.

The spinal column is composed
of bones (vertebrae) that are

PROPOSING EXPLANATIONS

separated by cartilaginous pads

simple task on a computer in a

(discs) that act as shock

room with plants, their produc

absorbers for the column.

tivity increased 12 percent when

Nerves run out through the

compared v.rith workers who

spinal cord to the periphery

performed the task in the same
room without plants .Addition
ally, people tested in the pres

through openings in the verte
bral bones. These nerves run

ence of plants reported feeling
about 10 percent more attentive

very close to the discs, which is
why protruding discs can cause
pain along those nerves. As a

after the task than those tested

result of an injury, an infection,
or a genetic predisposition, the

no one is quite sure what ac

without plants present. Though
counts for this phenomenon,

disc material can change consis

tency and produce pressure on

one researcher speculated that

the nerves that run out of the
spinal cord. This pressure pro

the presence of plants can lower
blood pressure. By somehow

duces pain along those nerves.4

causing us to be more relaxed,
plants help us to be more pro
ductive and focused.

Have you ever heard of the

Sports lllustrated Jinx? It seems

that whenever a college football

utor to the spread of sexually
transmitted diseases, according

mance on the field declines. This

to a government report that says

example of regression to the

20 cents could reduce gonor
rhea by up to 9 percent. The

raising the tax on a six-pack by

mean. In a series of events an
outstanding performance is
likely to be followed by one that

Centers for Disease Control and
Prevention study, released re

is more or less average

cently, compared changes in
gonorrhea rJ.tes with changes in

Two new drugs-angiostatin

alcohol policy in all states from
1981 to 1996. In the years fol
lowing beer tax increases, gon

and endostatin-have proved to
be very effective in combating
cancerous tumors in mice. The
drugs are unique for two rea

orrhea rates usually dropped
among young people.

sons . First, they are composed of
natural substances the body
makes, so they are less likely to

cause side effects. Second, they
stop the growth of cancer cells
by an indirect method. The
drugs eliminate the blood vessels
to the tumor and the tumor dies
because it is left without the

Cheap beer is a leading contrib

player is featured on the cover
of Sports lllustrated, his perfor

is nothing more than a simple

No one will ever build a flying
vehicle that is capable of hover
ing high in the air while sup
ported by nothing but magnetic
fields. This applies to inhabitants
of other planets as well. UFO
enthusiasts often claim that the

nourishment and oxygen that

flying saucers they "observe" are
held suspended in the air and

the blood supply provides

obtain their propulsion from a

A new study has shown that live
indoor plants may increase pro
ductivity and reduce stress.
When people performed a

self-generated magnetic field.
However, it is not possible for a
vehicle to hover, speed up, or
change direction solely by

CHAPTER THREE

means ofits own magnetic field.
The proof ofthis lies in the fun
damental principle of physics that
nothing happens except through
interactions between pairs of
objects. A space vehicle may
generate a powerful magnetic
field, but in the absence of an
other magnetic field to push
against, it can neither move nor
support itself in midair. The earth
possesses a magnetic field, but it is
weak-about one percent of that
generated by a compass needle.
For a UFO to be levitated by
reacting against the earth's mag
netic field, its own field would
have to be so enormously strong
that it could be detected by any
magnetometer in the world. And,
finally, as the magnetic UFO
traveled about the earth, it would
induce electric currents in every
power line within sight, blowing
out circuit breakers and in gen
eral wreaking havoc. It would not
go unnoticed. 5

& a boy swimming in the fun
damentally rather chilly waters of
Massachusetts Bay in sununer, I
discovered, as others had done
before me, that for comfort in
swimming, the water near the
shore was apt to be warmer
when the wind was blowing
onshore--towards the shore
than when it was blowing off
shore. By thoroughly
unsystematic statistical methods I
tested the discovery and found it
to be true. But why should it be
true? I shall try to give the essen
tials of what I believe to be the
correct, though obvious, expla
nation, without spelling it out in
all its logical, but boring, rigor.
Warm water tends to rise.
The sun warms the surface
water more than the depths. For
both reasons, surface water tends

to be warmer than deeper
water.The wind acts more on
the surface water than it does on
the depths, displacing it in the
direction of the wind.Accord
ingly, the onshore wind tends to
pile up the warmer water along
the shore, while an offshore
wind tends to move it away
from the shore, where, by the
principle that "water seeks its
own level," it is continuously
replaced by other water, which,
since it can only come from the
depths, must be relatively cold.
Therefore, water along the shore
tends to be warmer when the
wind is blowing onshore than
when it is blowing offshore.6
8.

Snow begins as rising mist from
the ocean or dew from leaves.
The molecules of water rise in
the warming sunshine, bound
ing around. They rise as vapor
until they are in the high cold
air and the vapor molecules
begin turning to solid water.
One solid water molecule joins
with another and then a third
one comes along. Soon they
form a six-sided figure. The
molecules keep a six-sided pat
tern as they grow into a six
sided flake.Water molecules,
made up of an oxygen and two
hydrogen atoms, hold on to one
another only in a certain way
that always forms a hexagon.7
FLORIDA MOTHER ACCUSED OF
MAKING DAUGHTER, 8, ILL

FORT LAUDERDALE, Fla.
Jennifer Bush, the Coral Springs, Fla.
girl who spent much of her eight years
beneath surgeon's knives, tethered to
tubes and pumped full of medicine,
will remain in state care until a judge
decides whether the child's mother
intentionally made her ill.

PROPOSING EXPLANATIONS

"We've got probable cause bey?nd
_
question," Broward Co�nty CtrcUlt
Judge Arthur Birken satd Tuesday as he
ordered the state social-service agency
to keep the child in protective cus
tody. Birken quoted the child's psy

white-colored fur serves as an
effective means of camouflage.
12.

chologist who said taking Jennifer
from her home would be the "safe"
decision. Health officials and prosecu
tors believe her mother, Kathy, has
Munchausen-by-proxy syndrome, a
psychological condition in which a
o
Y
·u
a
i

=�: ��fJ � : :��J=����!
10.

11.

In 1961, PresidentJohn F.
Kennedy, after meeting with his
advisors, approved a CIA plan to
invade Cuba (with 1400 Cuban
exiles) and overthrow the gov
ernment of Fidel Castro. The
invasion, at the Bay of Pigs, was a
total disaster. The invaders were
killed or captured, the United
States was humiliated, and Cuba
moved politically closer to the
Soviet Union. Why did the
President and his advisors arrive
at such a disastrous decision?
Psychologists have long under
stood that group members who
like each other and who share
attitudes and interests�like a
President and his most trusted
advisors....ft
.-....o en suffer from
group think�the tendency, in
close-knit groups, for all mem
bers to think alike and to sup
press dissent and disagreement.9
Polar bears have evolved their
white color as means of camou
flage.You see, polar bears are
predators and predators benefit
from being concealed from their
prey. Polar bears stalk seals rest
ing on the ice. If the seal sees
the bear coming from far away
it can escape. And since the
arctic environment is predomi
nately white, the polar bear's

A little known fact is that the
Spanish influenza of 1918 killed
millions and millions of people
in less than a year. Nothing
else--no infection, no war, no
famine--has ever killed so many
in such a short period."Why
then did people pay so little
attention to the epidemic in
1918 and why have they so
thoroughly forgotten it since?
The very nature of the disease
and its epidemiological charac
teristics encouraged forgetfulness
in the societies it affected. The
disease moved so fast, arrived,
flourished, and was gone before
it had any but ephemeral effects
on the economy and before
many people had the time to
fully realize just how great was
the danger.The enormous dis
parity between the flu's morbid
ity and mortality rates tended to
calm potential victims.Which is
more frightening, rabies, which
strikes very few and, without
proper treatment, kills them all,
or Spanish influenza, whi�h
infects the majority and kills only
two or three percent? For most
people, the answer is rabies,
without question.10

13.

A softly glowing ball of light
appears in the air nearby, hovers
for a few seconds, passes through
an object and then vanishes. It's
a phenomenon known as ball
lightning, which appears during
thunderstorms as a luminous
sphere about the size of an
orange or grapefruit.
Observers have reported

seeing ball lighming for
centuries, only to be greeted

with skepticism. Now, two
physicists from the Universidad

CHAPTER THREE

dates for jobs exceeds the num

Complutense in Madrid, Spain,
describe a possible explanation

ber of available jobs. Hence,

for ball lightning; something

fewer and fewer people opt to

called an "electromagnetic

train in that area, with the net

knot," in which lines of an elec

result that within a few years
there are not enough trained

tric or magnetic field join to

professionals to fill the available

form a closed knot.

jobs.When this happens, more

The researchers say the lines
of force are powerful enough to

people elect to train in the
underemployed area and the

trap a lump of the glowing, hot,

electrically charged gas that can
be created in a thunderstorm.
Temperatures in the ball may

cycle repeats itself.

Exerdses 16-25 all contain explanations.
For each, come up with at least one rival
explanation and then, �sing OckhamS
)Razor, try to decide whtch is most likely to
"' be correct.

reach more than 50,000 degrees '
F�renheit. But the energy soon(
...__,
dissipates, th knot unta�gles,

�

and the lununous ball disappears
into thin air.
14.

Societies without exception
exert strong cultural sanctions
against incest. Sociobiologist
E. 0.Wilson posits the existence

(

(Note: On page 51 a solution is provided
'
·,\for Exercise 16.)

Thinking about quitting school
for the sake of your mental
health? Think again. College
graduates across the mtion feel

ofwhat he terms, "a far deeper,
less :rational form ofenforcement;'

better emotionally and physically than high school dropouts

which he regards as genetic
Because ofrecessive genes,

because they have better jobs,
take better care of themselves,

children of incest carry a higher
risk than others of mental retardation, physical deformity, and

and have better access to health
care. A recent survey released by

early death; they are, therefore,
less likely to mate and reproduce

the Centers for Disease Control
and Prevention found that col-

than are children of parents who

lege graduates felt healthy an
average of26 days a month
while high school dropouts felt

avoid incest. Hence, individuals
with a genetic inclination
against incest contribute more
genes to succeeding generations.

The availability ofjobs in just
about every profession is bound
to ebb and flow. Today there is a
demand for teachers and a glut
of nurses. A decade ago, the
situation was just the reverse-
too many unemployed teachers
and not enough nurses. This is

all due to the fact that people
tend to opt for training in areas

good 22.8 days a month.
Academy award winners live
nearly four years longer than
their colleagues, according to a
study that credits the effect ofan
Academy Award on an actor's self
esteem. "Once you get the
Oscar, it gives you an inner sense
of peace and accomplishment
that can last for your entire life

and that alters the way your body

where jobs are currendy avail
able. & more and more people

copes with stress on a day-to-day
basis," says Donald A.
Redeimeier, a professor of medi

market, the number of candi-

Redeimeter found that Oscar

in that area come into the job

cine at the University ofToronto.

...._ _

PROPOSING EXPLANATIONS

winners live nearly four years

cluster to disassociate, allowing

longer than either actors who
were never nominated or those
who were nominated but did
not win. Multiple winners are
even more fortunate, living an

/.?
(JJ' ·

much smaller individual water
molecules to penetrate into the
�·jinnermost parts of the fabric.

£..2o/ A study done recently at Purdue
University found that religious

average of six years longer than

�

people are more likely to be

. .
thei silver-screen counterparts

overweight than nonreligious

.
A scientist who studies VISion
.
and the bram has made a cunous

people. In state-by-state com
parisons, obesity was found to
be the highest in states where

discovery about portrait paint
ing. Artists almost always place

religious affiliation was more
prevalent. Michigan, Mississippi,

one eye of their subject at the
horizontal center of the picture.

and Indiana were among the
states with the highest percent

Dr. Christopher Tyler took pho
tos of 170 famous portraits from

age ofoverweight persons. Like
wise, obesity figures were lower

the past five centuries and
marked the midpoint along the

in states that had the least num
ber of religious persons. Those

horizontal top of the picture.
Then he drew a straight vertical

included Massachusetts, Hawaii,
and Colorado. The author of the

line that divided each painting at
its horizontal center.To his as

study, Sociology Professor Ken
neth Ferraro, speculated that

tonishment, one eye or the other
almost always fell on or near the

American churches are virtually

horizontal center. In talking to
art experts, Tyler found that

silent on excess body weight,
despite a Biblical dictate for

ing an eye at the horizontal

Though gluttony is listed as a
sign of moral weakness, few

none knew of any rule for plac

moderation in all things.

center. He concluded that artists
must be doing it unconsciously
as the result of some intuitive
sense of the aesthetic appeal of
this arrangement.

19.

�

of coals. It seems that if you can
focus all of your powers of con

introduc�d called The Laundry
Solution. It consisted of a hard
plastic ball filled with a blue

the washing machine with your
laundry and everything will

come clean without the need for
soap! It seems that the ball con
tains specially structured water
that emits a negative charge

through the walls of the con
tainer into your laundry water.
This causes the water molecule

You ve probably heard or seen
stones about people who are
able to walk over red-hot beds

Recently, a new product was

liquid.Though the ball costs $75,
its makers claim that you will
never need to buy laundry soap
again. Just put the miracle ball in

religious groups have any proscriptions against overeating.

�
'

centration you can will your
body not to feel the pain and to
be inunune to the damage the

hot coals might otherwise cause.

Although the connection between conscious and uncon
scious thoughts have remained
obscure, psychologists theorize

that a link exists. Now scientists

have apparently provided some
proof the first physiological

evidence that unconscious brain
processes can control a seem
ingly voluntary act. The

CHAPTER THREE

researchers found that the brain

in the local newspapers. It seems

signals initiating muscle move

that the Pepsi-Cola Company

ment for clenching the fist begin

decided that Coke's three-to-one

before a person becomes aware
of deciding to do it. Benjamin

lead in Dallas,Texas

Libet, a psychologist at the Uni

missioned a taste preference

versity of California, asked five

study.The participants were
chosen from Coke drinkers in

was

longer acceptable, so they com

subjects to clench their fists

the Dallas area and asked to

whenever they felt like it. The
subjects remembered when they

express a preference for a glass of

became conscious of the desire

Coke or a glass of Pepsi.The

to do so by watching a special

glasses were not labeled "Coke"
and "Pepsi" because of the obvi

clock that enabled them to note
the time to within a fraction of a

ous bias that might be associated

second. Meanwhile, the
researchers monitored the sub

with a cola's brand name. Rather,
in an attempt to administer the
two drinks in a blind fashion, the

jects' brains for a kind of electri
cal activity called the readiness
potential that changes just before

Coke glass was simply marked
with a "Q" and the Pepsi glass

a person is about to use a mus

v.rith an "M." Results indicated

cle. Libet found that the readi
ness potential always changed

that more than half chose Pepsi
over Coke. It seems clear that,

about a third of a second before
subjects were aware of the deci

when the effects of advertising
are set aside, cola drinkers prefer

sion to clench their fists.

� A recent telephone survey of
\..:/ 113,000 Americans about reli

the taste ofPepsi to Coke.11

25.

From time to time, one hears
stories of strange, almost unbe

gious affiliation came up with
some rather interesting facts.
Perhaps the most interesting was

lievable animal behavior. Pets,
for example, seem to sense

that, while nationwide 7.5 per
cent of the respondents said
they belonged to no church,

return. Dogs and cats have been

when their masters are about to
known to move their young to
a safe place just before an earth

15 percent of the sampled resi
dents of Oregon,Washington,

quake. There are many docu
mented cases in which animals

and California claimed no reli
gious affiliation. It seems clear

have reacted strangely to their
impending death or that of their

that all the"new age" mumbo
jumbo that goes on out west is
turning people away from God.

masters. These incidents involve
knowledge that came to the
animals in some apparendy
paranormal way. There is no

The following story appeared

apparent explanation for
them-except ESP.

about an advertisement in a
weekly news magazine as well as

A S O L U T I O N TO E X E R C I S E 1
a.

W'hat is being explaineJ? The

W'hat is the explanation? Nerves

manner in which a protruding

run very close to discs and

disc can cause nerve pain.

when discs are injured, infected,

I
- __.l

PROPOSING EXPLANATIONS

etc., they can change consis

intervening causal mechanism:

tency and protrude. This in turn

the sequence of events, begin

causes pressure on the nerves,

ning with damage to a disc and

which results in pain.
c.

ending in lower back nerve
pain. The passage also gives a

W'hat ifany recognizable sorts of

functional explanation of the

explanatory claims occur in the

vertebral discs: they serve as a

explanation? The passage explains
a disc problem can cause nerve

kind ofshock absorber.

pain. It does so by discussing the

A S O L U T I O N TO E X E R C I S E 1 6

One possible rival explatuition is that college

graduates are more likely to exaggerate when
asked to assess their own condition than are
high school dropouts, so that the results we
are trying to explain are largely illusory. The
explanation in the passage seems more in
keeping with Ockham's Razor.Aaess to

health ca.re and job success and contentment
seem to bejust the sorts of things that would
contribute to a sense ofpersonal well-being.
By contrast, it seems more than a little odd
to suggest that a tendency to exaggerate
increases with education. Why on earth
should this be the case?

N OTES
1. This example is adapted from Nuts
and Boltsfor the Soda! Sdences, by Jon
Elster, a very readable account of
prominent causal mechanisms used in the
social scientific explanation
2. The studies on which this example is
based describe the situation before a
vaccme for hepatitis B was developed. It is
interesting to note that before the advent
of the vaccine, chances of dying from
accidental exposure to hepatitis B were
almost identical to those today associated
with accidental exposure to HIV Yet the

without introducing the notion of
correspondmg abstract entities.
4. Hister,Art. Dr. Art Hister's Do-it-yourself

Guide to Good Health. Toronto: Random
House, 1990, p. 178.

5. Rothmnun, Milton A. A Physicist's

Guide to Skeptidsm. Buffalo: Prometheus
Books, 1988, pp. 148-149.
6. Homas, George. The Nature of Sodal
Science. NewYork: Harcourt, Brace
World, 1967, p.21.

hepatitis B risk received much less

The Oregoninan, Jan. 2 1 , 1993 .

accidental HIV exposure in the medical

News Service, in The

attention than that given today to
conununity.

3. The use of"razor" here derives from
the fact that Ockham used his principle to
"shave away" certain metaphysical entities
in which philosophers of the time
generally believed. Ockham used the
razor, for example, to argue that
abstractions are not "real" things over and
above the words used to express them

One can, on Ockham's view, account for
the significance of such expressions

7. Marvin, Rob. "What in the World."
8. Donna Leinwand. Knight-Ridder

1996.

Oregonian, Apr. 17,

9. Adopted fromWade andTavris
Psychology, 2nd ed. NewYork: Harper
Collins, 1990

10. Crosby, AlfredW. America's Forgotten

Pandemic: The Influenza # 1918.

Cambridge: Cambridge, 1989, p. 321
11. Adaptedfroma case study in Huck,
SchuylerW, and Sandler, Howard M. Rival

Hypotheses. NewYork: Harper & Row; 1976

Testing Explanations

THE BASIC METHOD

uppose we've made a set o f observations and have uncovered something

unusual. We have our suspicions about what might e�lain it but we are
not sure. Now, we need to find a way to test our susp1crons. In this chap
ter we will introduce the basic strategy involved in scientific tests. Then, in

Chapter 5 we will focus on the way this strategy plays out in one very com
mon and important type of scientific research---studies designed to investigate
large scale causal relationships.
How do we go about putting an explanation to the test? The basic strategy
is really very simple. We begin by trying to find something that ought to hap
pen if the explanation is correct. Suppose I've just flipped the switch on my
desk lamp and nothing has happened. My guess is that the bulb is burned out.
If I'm right, then it follows that if I remove the bulb I ought to be able to spot
a break in its filament. Next, I check the bulb to see if I am right. If the ftla
ment is ruptured, I've confirmed my suspicions. However, if the bulb is in

working order I now have evidence that my explanation is wrong. Something
else must be causing the problem. This simple strategy-making and testjpcr a

prediction1 associated "'With an explanation-is at the heart of the method �
which ideas are put to the test in science.

As we shall soon see, however, explanation testing is rarely as straightfor
ward as in the case we just considered. It may be difficult to setde on a pre
diction that can provide unambiguous evidence for an explanation. Unlike our
52
__L__

TESTING EXPLANATIONS

example, moreover, we cannot test every explanation by simply looking to see
what is the case in the natural world. Often, the testing of an explanation
requires the creation of artificially imposed circumstances designed specifically
to yield a decisive prediction. The net result is that a great deal ofeffort is often
required to design and execute a competent scientific test. To get a grasp of the
problems that may be encountered in designing and carrying out an experi
ment, let's look at a few case studies from the world of science. Along the way,
we will set forth two criteria that any good scientific test satisfy.

H O W T O T E S T A N E X P L A N AT I O N
One of the more interesting episodes in the history of science involves the the

ory of spontaneous generation. As recently as the late 1800s many people

believed that living organisms could be generated from nonliving material.

One physician in the seventeenth century, for example, claimed that mice arose

from a dirty shirt and a few grains of wheat placed in a dark corner. Similarly,

it was thought that maggots-tiny white wormlike creatures, the larval stage of
common houseflies-were generated spontaneously out of decaying food. In
1688, an Italian physician, Francesca Redi, published a work in which he chal
lenged the doctrine that decaying meat will eventually turn into flies. The fol

lowing passage is from Redi's

Experiments in the Generation of Insects:

. . I began to believe that all worms found in meat were derived
directly from the droppings of flies, and not from the putrefaction of meat,
and I was still more confirmed in this belief by having observed that,
before the meat grew wormy, flies had hovered over it, of the same kind as
those that later bred in it. Belief would be vain without the confirmation
ofexperiment, hence in the middle ofJuly I put a snake, some fish, some
eels from the Arno and a shce of milk-fed veal in four large wide
mouthed flasks; having well closed and sealed them, I then filled the same
number of flasks in the same way, only leaving these open.1
In this passage Redi does a number of things. He tells us of the observations

that led him to his explanatory hypothesis and then gives us his explanation.

Next, he describes the test he carried out. Though he doesn't explicitly set
forth his prediction, it seems clear from what he says. Here are the various ele
ments of his test:

Explanation: worms (maggots} are derived directly from the droppings
of flies.

Experimental conditions: two sets of flasks are filled with meat or fish. One
set is sealed and the other is left open so that flies can enter.

Prediction: worms will appear only in the second set of flasks.
Is Redi's test a good one? Is it, in other words, sufficiently well designed
to enable him to decide whether his explanation is correct? To answer these

CHAPTER FOUR

questions, we need to look at the conclusions we would be justified in draw
ing given the experiment's two possible outcomes.

Consider first what follows if the predicted result fails to occur-if worms

appear in the sealed flasks as well, or if there are no worms in either set. Are we
entitled to reject Redi's hypothesis? The answer here is not as clear as it may
seem. What, for example, if the seals were not perfect? Perhaps then flies may
have contaminated the sealed containers. Or what if flies for some reason did

not lay eggs in the unsealed flasks? If either of these possibilities is the case, it

may be that Redi's hypothesis is right after all. So we can reject Redi's expla
nation, but only provided we have no reason to suspect anything has happened

to compromise the experiment, anything, that is, like the two possibilities
above. One feature of a well designed experiment, then, is that it will take suf

ficient precautions to ensure that the prediction ought to occur if the expla
nation is right. If the sealed flasks have not been compromised, and if both sets

were exposed to sufficient numbers of flies, Redi's experiment meets what we
might call the falsifiability criterion:
A good test will be designed to rule out factors that could account for a
failed prediction even if the explanation is correct.
If this criterion is met, an experiment will enable us to reject a faulty explana
tion. If we are sure that something will happen if the explanation is right, and
if that something fails to occur, we can conclude that the explanation must be

wrong.Though we can hardly expect to anticipate all ofthe things that could
go wrong in designing and carrying out an experiment, it is always worthwhile

to pause and think about potential problems that might compromise the
results. For example, in any experiment involving an apparatus (like Redi's
flasks) we would do well to make sure the apparatus is operating properly.
Consider next what follows if the predicted result occurs. In fact, Redi did
get the results he expected. The passage continues:
It was not long before the meat and fish, in these second vessels, became
wormy and flies were seen entering and leaving at will; but in the closed
flasks I did not see a worm though many days had passed since the dead
flesh had been put in them.
Has Redi established his explanation? Can we be sure the worms are due to
fly droppings? Once again, the answer requires a bit of qualification. Before we
embrace Redi's explanation, we must be sure that nothing else---other than fly
droppings-could account for his results. Many scientists of Redi's time
believed in the doctrine of spontaneous generation and looked upon his results
with some suspicion. They speculated that there might be some "active princi
ple" in the air necessary for spontaneous generation. By depriving the meat and

fish in the sealed containers of a sufficient flow of fresh air, they reasoned, Redi
may have inadvertently prevented the spontaneous generation of worms. Thus,
it seems at least a possibility that Redi's explanation is wrong even though his
prediction turned out to be right.
In light of this objection, Redi modified his experiment. Rather than seal
ing the first set of flasks, he covered them with a "fine Naples veil" that kept

TESTING EXPlANATIONS

QUICK REVIEW 4.1

Falsifiability and Verifiability

To be well designed, an experiment
must meet two criteria:
Falsifiability-A good test will rule
out factors that could account for
a failed prediction even if the
explanation is right.
Verifiability-A good test will rule
out f�ctors that could explain a

successful prediction if the
explanation is wrong.
A test that does not meet the
falsifiability criterion cannot reject an
explanation. One that does not meet
the verifiability criterion cannot
confirm an explanation.

flies from coming into contact with the meat and fish but did allow air to cir

culate. Carrying out this modified experiment Red.i once again obtained the

expected results: worms appeared only in the covered flasks. By this maneuver
Redi

was

able to rule out the possibility that some something in the air might

be responsible for his results .As a result, the conclusion that fly droppings were
responsible for the worms was on a much stronger footing. The modification

Redi needed to make to test his explanation suggests a second criterion that a
decisive explanatory test must satisfy:

A good test will be designed to accommodate factors that could account
for a successful prediction, even if the explanation is wrong.
This second requirement is called the

verifiability criterion because

we cannot

accept a test as having verified an explanation unless we have good reason to
believe that nothing else could have accounted for the predicted result.
In tests of causal explanations like Redi's, experimental and control groups
will often be used to satisfY the verifiability criterion. The members of the two
groups will differ in only one respect. The experimental group but not the

control group will be subject to the suspected cause. (In such experiments, the

suspected cause will sometimes be called the independent variable and its

claimed effect, the dependent variable.) The prediction, then, will be that only
members of the experimental group will respond in the appropriate way. Thus,
in Red.i's second test, the experimental group was composed ofthe bits ofmeat

and fish in the veil-covered flasks and the control specimens were those in the
open flasks. His prediction was that worms would be found only in the latter
group, the open flasks. Control groups provide an effective counter to the nag
ging possibility that some unknown explanatory factor may have been over
looked, something that may account for a successful outcome even if the
explanation is wrong. For if the experimental and control groups are identical

it is hard to imagine some factor other than the suspected cause that could be
responsible for the predicted difference in outcomes between the two groups.

One further feature ofRedi's work is worth noting. Under naturally occur
ring conditions it would probably have been impossible to isolate specimens of
meat and fish having absolutely no contact with flies. To test his explanation

CHAPTER FOUR

Redi found it necessary to put his specimens in a somewhat unnatural envi
ronment. But explanation testing does not always involve the kind of con
trived, "laboratory" conditions required by Redi. Sometimes nature will pro
vide the clues necessary to test an explanation. Consider, for example, the test
described in the following news story.

Satellite Supports "Big Bang"Theory
Phoenix-A NASA satellite has provided powerful evidence supporting
the "big bang" theory, which holds that the universe began over 15 billion
years ago with the most colossal explosion ever.
John C. Mather, an astronomer with the space agency, said Thursday
that precise measurements by the Cosmic Background Explorer satellite of
the remnant energy from the big bang given readings that are exactly

the theory predicted.
The theory, first aired in the 1920s, posits that all matter in the universe
was once compressed into

exceedingly small and super-heated center

that exploded, sending energy and particles outward uniformly in all
directions. At the moment of the explosion, temperatures would have
been trillions and trillions of degrees and have been cooling ever since.
If the theory is correct, astronomers expected an even distribution of
temperatures just fractionally above absolute zero to still exist in the
universe as an afterglow from the explosion.
Mather said that a Cobe instrument called the Far Infrared Absolute
Spectrophotometer has now taken hundreds of millions ofmeasurements

across the full sky and has determined that the primordial temperatures are
uniformly distributed. He said the uniform temperature left from the big

bang is 2.726 degrees above absolute zero--or about minus 456.9 degrees F.2

This story reports on the results of an experiment done to provide new evi
dence for an explanation most astronomers and cosmologists accept: the big
bang theory. (Even the most well entrenched explanations can benefit from
further confirmation, particularly if they involve elements-like the big bang
theory-that cannot be directly observed.) The theory predicts a uniform tem
perature throughout the universe and consists of millions of measurements
taken across the full sky.
Now, this experiment clearly satisfies the falsifiability criterion, unless we
have some reason to suspect the apparatus used to take the measurements. If
the big bang theory is right, there should be a uniform afterglow and it ought
to be detectable using the techniques mentioned. But does it meet the verifi
ability condition? Can we, in other words, rule out the possibility that some
thing else might explain the predicted result? Perhaps not, if the prediction
were simply that there should be a uniform temperature throughout the uni

verse. Other cosmological theories might be able to account for the unifor
mity. Or a successful match between prediction and actual outcome may be a
matter ofhappenstance. Mter all, the universe either has a uniform background
temperature or it does not. Perhaps the match was just a bit of luck. But the
actual prediction involves a bit more. The story goes on to say:

TESTING EXPLANATIONS

Craig Hogan, a University of Washington astronomer, said the new research
"is verifting the textbooks" by providing powerful evidence for the theory.
Hogan said that the Cobe results exacdy match the theoretical curve of
temperature energy decay that would be expected in the big bang theory.
This new passage suggests the verifiability condition is met, largely because of
the specificity of the prediction. The big bang theory predicts a very specific
temperature at a very specific time in the development of the universe. And, as
it turns out, the universe is just as advertised. The close fit between prediction
and experimental outcome would be hard to explain if the big bang theory

were wrong!

Natural observations can also yield evidence that an explanation may be
wrong. Here is another recent news story pertaining, coincidentally, to the big
bang theory:

Discovery Qffers Fresh Insight into Makeup cif Universe
Astronomers have discovered a pair of collapsed stars, remnants of
catastrophic supernova explosions, that may be composed entirely of free
quarks, the never before observed building blocks of the protons and
neutrons that make up normal matter. The discoveries imply that long
standing theories governing how stars die when their nuclear fuel is

exhausted need a major overhaul to explain the existence of "strange
quark stars," the last possible step before the ultimate collapse into a
black hole.'
The story describes the work of David Helfand, an astronomer at Columbia
University, using NASA's Chandra X-Ray Observatory. Helfand examined a
spinning pulsar 10,000 light years away known as 3C58. The story goes on:
Neutron stars cool offby radiating tiny particles called neutrinos. After
10 years, such a star's temperature should be about 5 million degrees. After
that, it cools more slowly. Given its age, Helfand expected the temperature
of 3C58 to be a bit less than 2 million degrees. "Our observations show in
the case of this remnant that the temperature is far lower than that and the
energy being radiated is down by at least a factor of10 from what was
expected," he said. "This observation requires a fundamental revision in
our models of the structure and evolution of neutron stars."
Prevailing "models of the structure and evolution of neutron stars" predict the
temperature of 3C58 should be a bit less than 2 million degrees. But the mea
surements taken by Helfand suggest its temperature is much lower. The
received explanation-the currently accepted model-predicts a certain tem
perature, but observation reveals that the predicted result is quite wrong. If
there is no way of accounting for this discrepancy as an artifact of the tech

niques used to make the measurements, this experiment makes quite a strong
case against the prevailing model.
It is rare for a big idea in science to be verified or falsified by the results
of a single experiment. Typically, the results of one test will provide tentative

CHAPTER FOUR

QUICK REVIEW 4.2

Designing a Decisive Test for an Explanation

Imagine experimental conditions under which something very specific
the prediction-should happen if the explanation is right.

Modify
experimental
design to
accommodate
problems.

evidence and point in the direction of needed further experimentation, much
as Redi 's initial experiment pointed to the need for a further experiment

involving free flowing air. Even after Redi had confirmed his explanation,
much remained to be done. Building on the work of Redi and others, later
researchers were able to look much deeper into the phenomenon Redi had
documented. Their work made use of a new scientific instrument, the micro
scope, to observe the behavior of bacteria and other microorganisms to refine

TESTING EXPLANATIONS

the explanatory ideas developed by Redi. Similarly, the negative results ofa sin
gle test will rarely be sufficient to overturn an explanation, especially if it has
been well confirmed by previous experimental results. No doubt current ideas
about the structure and evolution of neutron stars will be modified in light of
the experimental results discussed above. But the larger theory of which it is a
part-the big bang theory-will remain intact though slightly modified to
reflect these results.

H O W N O T TO T E S T A N E X P L A N A T I O N
We have said that a decisive test must satisfy two criteria-falsifiability and ver
ifiability. Perhaps the most effective way to underscore their importance is by
looking at an experiment in which neither is satisfied. The experiment

described in the following passage is intended to shed light on the question of
whether or not animals have ESP.

At mealtime you might put out two feedpans instead of one for your dog
or cat. The feedpans should be located so that they are equally convenient
to the animal. They should be placed six to eight inches apart. Both
should contain the same amount of food and avoid using a feedpan the
animal is familiar with. Pick the dish you wish the animal to eat from and
concentrate on it. In this test, the animal has a 50% chance of choosing
correctly half the time.You may want to keep a record of his responses
over several weeks to determine how well your pet has done.4
The explanation under scrutiny here is that animals are receptive to human
thoughts via ESP and the prediction is that, under the experimental conditions
outlined, pets

will pick the dish we are

thinking of more than 50 percent of the

time. (Not a 50 percent chance "halfthe time" as the author of the passage claims!)

Is the test described in the passage a good one? First we must ask whether

it meets the falsifiability condition. Is there anything that could account for a
failed prediction if the explanation is true? Suppose you were to say to your
pet, in an entirely monotonous tone ofvoice,"Eat out of the red dish, the dish
on the left, Fido." I doubt Fido would grasp the meaning of your words.
Domestic animals tend to react to a complex of behavioral cues, some given
by vocal inflection, but not to the meaning of words uttered in their presence.
Thus if saying aloud, "eat out of the red dish"will not do the trick, it is doubt

ful that thinking the same thing silently will work. Nor will it do to "picture"

in your "mind's eye" the red bowl. I doubt Fido would react in the appropri
ate way to an actual picture of the bowl, so it seems highly unlikely Fido would
react to nothing more than a "mental picture" of the red bowl. Thus, under the
experimental conditions described in the passage, it seems entirely possible that

Fido may fail even if he or she has some incipient extrasensory powers. A failed

prediction, then, would not entitle us to conclude that animals do not have
ESP unless

are Vlfilling to grant the entirely dubious claim that animals can

understand human thoughts and words.

CHAPTER FOUR

Does the test satisfY the verifiability condition? Is there anything that could
account for a successful outcome if the explanation is false? A number of things
come to mind here that might explain a successful outcome. First, suppose that
our subject tended to go to one bowl instead of the other. It is possible that
the experimenter, who is both sending the instructions and observing the out

come, will inadvertently think of the dish the pet favors. Second, domestic ani

mals are very good at discerning nonverbal cues. It may be that the experi
menter is inadvertently looking at or standing in the direction of the dish being
thought about and the experimental subject is picking up these cues. Finally
there may be some bias at work on the part of the experimenter. Suppose our
experimenter were convinced in advance of doing the experiment that animals
have ESP. In recording or evaluating the subject's responses, the experimenter
might inadvertendy leave out responses that would othern·ise provide evidence
against animal ESP.
As you can see, the experimental test sketched in the passage is poorly
designed in that it will enable us to conclude neither that pets do or do not have
ESP. The kind of analysis we have just completed should be done as a part of
the design of any experiment. If our first attempts at designing an experiment
fail to satisfY our two criteria we can go back to the drawing board armed with
what we have discovered about potential weaknesses. Our subsequent design
efforts are bound to do a more effective job of satisfying our two criteria.

T E S T I N G E X T R A O R D I N A RY C L A I M S
With a few modifications, the experimental strategy used t o test explanations
can be used to test extraordinary claims of the sort discussed in Chapter 2.
Consider one such claim. People, known as "water witches" or "dowsers" claim
they can detect water with a simple forked wooden branch. Dowsers loosely
grasp one of the forks in each hand and point the branch straight ahead, par
allel to the ground When they approach a source of water, the dowsing rod, as
the forked stick is called, will point in the direction of the water, much as a
compass needle will point in the direction of magnetic north. Many successful
dowsers claim to be able to pinpoint sources of water for purposes of well
drilling and some even claim to have found water where conventional geolo
gists have failed.
As with most extraordinary claims, the evidence for dowsing is sketchy. We
must rely on the testimony of dowsers and their clients about past perform
ances. Moreover, the fact that a dowser, say, points to a location, a well is drilled
and water discovered does not show that the dowser actually located water

with his or her dowsing rod. That water was found at the indicated location

may have been a coincidence, or there may have been vtsual clues to aid the
dowser-patches of greenery near the chosen location, etc. And we have no
real sense of dowsers' success rates, other than what they and their clients
report. How often are they mistaken? Our challenge, then, is to devise an

_ __

TESTING EXPLANATIONS

experiment that will give us decisive evidence, one way or the other, about the
dowser's claimed ability.
To satisfY the falsifiability condition, we need to come up with a set of con
ditions under which nothing could explain a dowser's failure other than an
inability to find water with a dowsing rod. A good rule of thumb in setting up
tests of extraordinary claims is to consult the experimental subject or subjects
prior to designing the experiment. We want to set up conditions under which
the experimental subjects will agree, in advance, that they ought to be able to
perform. Otherwise failure in the actual test may be taken to show only that
the experiment is hostile to the ability we are attempting to test. But if our
subjects concur that the experiment approximates conditions under which
they should be able to perform, such excuses lose much of their steam. If a per

son says he or she can perform under a given set of conditions, it is hard to take

seriously protestations to the contrary particularly after a failed test.

To satisfy the verifiability condition we need experimental conditions
under which nothing could explain our subject's success other than a real abil

ity to dowse. What we want to try to rule out is the possibility of cheating,
coincidence, inadvertent cuing on our part, visual or audio clues

to where

the water is, and the like. If we succeed in imposing controls sufficiently tight
to rule out these possibilities, success by the dowser can be taken to vindicate
his or her claimed extraordinary ability.
Now that we have a sense of what a good experiment ought to involve,
let's try our hand at actually designing one. Imagine

have contacted a group

of the country's most well known and successful dowsers and all have agreed
to take part in our experiment. We propose the following test.We will place
before each dowser ten identical large ceramic jars with covers, arranged in a
straight line equidistant from one another. Only one of the jars will contain

water. The other nine will be empty. The dowser will be allowed to approach
each jar but not to touch any jar.We will only test subjects who agree that they
should be able to find the single jar with water. f:We might give them a chance
to dowse a jar they know contains water to insure that the experimental con
ditions meet their approval.) If a dowser is successful, he or she will be retested
once the jars are rearranged. Of course, our subject will be asked to leave the
room while the jars are being rearranged. As an additional precaution, no one
who knows the location of the jar containing water will be allowed to be in
the room while a dowser is being tested.

With all of the precautions we have built in, our experiment is well
designed to provide unambiguous results. If a dowser can perform under such
conditions we have strong evidence for dowsing. The odds of choosing the
right jar in the first run are one in ten, in the first and the second, one in a

hundred. It is hard to imagine anything other than dowsing that could explain
such results in our tightly controlled experiment. If, instead, the dowsers fail, it
would be hard to explain away the results given that the subjects have agreed
that they should be able to perform under the test conditions.
One feature of our test deserves special note.We have been careful to arrive
at a prediction that sets a clear line of demarcation between success and failure.

CHAPTER FOUR

If our dowser can find the jar containing water in two successive trials, he or
she is successful; anything less constitutes failure. In designing controlled tests
it is important to avoid predictions that blur the line between success and
failure. Imagine, for example, we had decided to test our dowser by burying
containers of water a few feet below the surface of a vacant lot. The dowser
would then be instructed to place markers where he or she believed the con
tainers to be located. Suppose the dowser placed markers within three or
four feet of the location of one of the containers. Does this constitute a hit
or a miss? Just how far off must a marker be before we consider it a miss? Or
suppose markers are placed at ten locations when only five containers were
buried and that seven of the markers are within a few feet of one or the other
of the containers. How do we evaluate these results? Has our dowser suc
ceeded or failed?
The line between success and failure can be very difficult to draw when a
prediction involves some sort of subjective impression on the part ofthe exper
imental subject. Imagine, for example, we were to test a telepath-someone
who claims to be able to read the thoughts of another. As part of our experi
ment we instruct the telepath to sketch a simple picture that someone in
another room is concentrating on. Suppose the person in the other room is
looking at a postcard of a small sailboat moored at a marina and that the
telepath produces a simple drawing that includes a vertical straight line and a
narrow triangular shape that might correspond to a boat hull or sail.To make
matters worse, several of the drawing's details conform clearly to nothing we
can discern on the postcard. Is the telepath's impression accurate or inaccurate?
Presuming we can decide what constitutes a detail or feature of the picture on
the card, how many features or details must the telepath get right to be a clear
indication of success?
To take another example, imagine a tarot card reader were to give a per
sonality analysis, based on the position and order of the cards, of someone
unknown to the reader. The reading might indicate that the person in ques
tion, say, "tends to be optimistic despite occasional moments of depression or
pessimism" or "makes friends easily" or "displays clear leadership ability." How
do we evaluate such claims? The problem here is not only with the generality
of the predictions but with the lack of a clear basis for judging them. We must
first arrive at an accurate personality profile of the person in question. Pre
suming we could do this, what objective basis do we have for comparing our
profile with that of the tarot card reader? No doubt any two sets of subjective
impressions about a person's character will contain some words and phrases in
common. How much similarity is required to put some stock in the analysis of
the tarot card reader?
In designing a test, then, it is crucial that we arrive at a prediction that
clearly spells out the difference between success and failure. If in evaluating the
results of a test we are unable to say precisely whether our subject has suc
ceeded or failed, then our test has very little point. Fortunately, however, the
prediction in our dowsing test seems to be clear and unequivocal; success and
failure are clearly spelled out.

TESTING EXPLANATIONS

QUICK REVIEW 4.3 Testing for an Extraordinary Ability

No matter how well they are designed, tests of extraordinary abilities face

a further difficulty. Suppose we run our test and all of our dowsers fail. Believ

ers in dowsing are likely to explain away our results on the ground that we
have tested the wrong people, that our experiment is flawed in ways neither
we nor they understand, or even that dowsing only works "in the field" under

noncontrolled conditions. They will probably go on to point out that dowsing

has been practiced for hundreds of years; the earliest record of a successful

dowsing dates to 1586, in Spain. Such objections are nearly impossible to
counter, but for this reason they lack any real credibility. They boil down to
nothing more than the claim that dowsing cannot be tested. We need only

64
reply that if it cannot be tested, then we have no reason to believe it works!
Dowsing is something of an anomaly and as we found in Chapter 2, the bur
den of proof lies with the believer, not the skeptic. Lacking any clear experi
mental evidence for dowsing, then, it is reasonable to assume that dowsing does
not work.

S U M MARY
The basic strategy used t o test a n explanation i s always the same. Isolate a pre
diction that will occur if an explanation is correct.

Tests can be undertaken

under laboratory conditions where circumstances will be arranged to yield a
prediction, or in the real world by checking the prediction against the facts. In

either case, the prediction must enable us to reject the explanation ifit is wrong

and to confirm it if it is correct. To accomplish this, any experiment must sat
isfy two criteria. First, it must rule out factors that could account for predictive

failure even if the explanation is correct (the falsifiability criterion) . Second, it
must rule out factors that could explain predictive success even if the explana
tion is wrong (the verifiability criterion). By a similar experimental strategy,
extraordinary claims and abilities can be- tested. In such a test, care must be taken
to insure that the predicted outcome is dear and measurable and that the sub
ject or subjects believe they can perform under the conditions specified.

EXERCISES

Exercises 1-10 involve explanations and
extraordinary claims or abilities. For each,
design a decisive test, that is, one that
satisfies both the verifiability andfalsifia
bility criteria. In the case qf extraordinary
claims and abilities, particularly, make sure
the predicted dtfference between success tmd
failure is clear and measurable. Be prepared
to modify yourfirst rfforts when yythm" would be
"critical."As a result, his condi
tion would be unstable, putting
him in danger of a relapse.
Few listeners took Thom

129

men's warning seriously. Gable

days, and then comparing them

and his doctors were probably
unaware of it. On Wednesday,

with your experiences of up and
down days, of illness and health,

130

CHAPTER SIX

of success and failure, you will
be able to judge for yourself.

15.

For years, stories have been cir
culating about an internal com
bustion engint>, invented
sometime in the 1950s, that
burns a simple combination of
hydrogen and oxygen, instead of
gasoline. This "water engine" as it
is sometimes called, could revo
lutionize the world economy
freeing us of our dependence on
fossil fuels and making trans
portation virtually free to every
one. But don't hold your breath.
The major players in the global
economy are a tight confedera
tion of industries and countries
involved in the manufacture,
maintenance, and fueling of
automobiles. So enormous is the
global monetary investment in
the status quo that it is virtually
impossible that the water engine
will even see the light of day.The
major oil and automotive com
panies have seen to it that all
patents pertaining to this revolu
tionary new invention are under
their control and they have or
chestrated the suppression of all
information about this incredible
new invention that would, if
marketed, cost them billions of
dollars. Ask any representative of
the oil or automotive industry
or any government official for
that matter-about the water
engine and I predict this is just
what you will hear: either "no
comment" or"there's simply no
such thing."

16.

Thefollowing newspaper article
appeared under the heading, "Ex
USO Professor Theorizes About
Alien Beings:''

Aliens from distant worlds maybe
watching earth and making unofficial

contact with selected humans, says a
recently retired scientist at Oregon
State University. His theory is that
advanced and benevolent space beings
may have adopted an embargo on
official contact with earthlings, wish
to avoid the chaos that could
sweep the planet if their presence
were suddenly revealed.
Instead, they have adopted a
"leaky embargo" policy that allows
contact only with citizens whose
stories are unlikely to be credible to
scientists and the government, said
the scientist, James W Deardorff, 58,
professor emeritus of atmospheric
sciences.
'They just want to let those know
who are prepared to accept it in their
minds that there are other beings,"
Deardorff said "They may want to
slowly prepare us for the shock that
could come later when they reveal
"
themselves.
Deardorff is prepared to accept
many ideas �oo�ed upon skeptically by
other scientists, mduding telepathy
and the possibility of time travel and
physical dimensions other than space
and time.
His open-mindedness has made it
more difficult to operate in the scien
tific mainstream, where scientific
committees have been formed to
debunk theories about UFOs and
psychic phenomena.
"There's a l�t of polarization going
_
on now," he sa1d, adding
that he has
had trouble getting some papers on
extraterrestrials published in scientific
journals. "There's a lot less middle
ground than there used to be;• he said
"lt:s n� accident that I'm getting more
acnve tn this area now after
retirement."11

ing

17.

I have a new theory about that
most mysterious of forces, grav
ity. Though physicists can de-

FALLACIES IN THE NAME OF SCIENCE

experimenter instructs the com
puter to proceed, one number at

scribe for us the laws which
gravity follows, they have failed

a time. Prior to the generation

entirely to explain the mecha

of each number, an experimen

nism by which gravity works. I
think I have the answer. Every

tal subject is instructed to think

massive object in the universe

"odd" or "even" and then to

generates invisible, spring-like

mark down their choice on a

tendrils in the direction of every

tally sheet. The experimenter

other object in its inunediate

then instructs the computer to

vicinity. When these tendrils

generate a number and the

connect, they function like a

result is tallied against the

coiled spring, with the tension

choice of the experimental
subject. Several hundred trials

varying in direct proportion to
the product of the masses of the

are run in this way. Under these
experimental conditions, it is
predicted that subjects with

objects they connect and in
inverse proportion to the square
of the distance between the
objects. I call these tendrils "vir

telekinetic ability will score

tual springs."Thus, virtual
springs grow in strength as ob

predict, i.e., the computer and

much higher than chance would
the experimental subject will
agree more than 50 percent of
the time.

jects are closer together and
weaken as objects recede from
one another. That I am on to
something remarkable is sug
gested by the following. If my
virtual spring theory is right,
objects of differing masses

should all accelerate toward
another massive object, say, the
surface of the earth, and, more
over, should do so at roughly the
same rate. By careful experimen
tation I have established the
truth of both these predictions.
Massive objects all tend to fall
toward the earth and tend to do
so at precisely the same rate of
acceleration, irrespective of mass!
18.

131

Telekinesis is the ability to bring
about physical changes by
purely mental processes. Is
telekinesis for real? Consider the

19.

Recently, I carried out a telepa
thy experiment on 50 ofmy
students. I shuffled a standard
deck of playing cards. Sitting
behind a screen that blocked me
from my subject's line ofsight, I
turned over the cards one at a
time. I would concentrate on the
value of the care--ace, three,
king, etc.-and then instruct the
subjects to record what they
thought the card was. I did this
for the entire deck. Now, simply
guessing, we would expect
someone to get about 8 percent
right (1/13).And indeed, none
of my subjects scored much
higher or lower than this. But

that is not the end of the story!
Close analysis of the results

following experiment. A com
puter is programmed to gener

shows that several students were
within two cards of the card I

ate numbers at random. When
an odd number is generated, the

was

computer prints out "odd," and
when an even number is gener
ated, it prints out "even." An

concentrating on nearly half
the time! It seems clear to me
that these subjects have demon
strated at least some ability to
pick up thoughts telepathically.

CHAPTER SIX

132

20.

From aflyer advertising a chiroprac
tic clinic:

bookends and other elephant figurines

all around the house.

Ronald Pero, Ph.D., researched the

One man had an unpleasant life on
a ship which ended when he was tied

immune system at the University of

and thrown overboard into the ocean

Lund Medical School, Lund, Swe

and drowned.The man had always

den, and the Preventative Medical

been afraid of water in this life and

Institute, New York City. He meas
ured both immune resistance to
disease and the ability to repair ge
netic damage.
In a news report about his study in

East/JtM>stjoumal, November 1989,
chiropractic patients were compared
to two groups: normal, healthy people,

never learned to swim. I worked with
this man to bring the drowning expe
rience into the present time and

helped him to release the emotions
and fear connected with it. A month
later he was swimming and inner
tubing in Timothy Lake with his wife
and sons.

and cancer patients. The chiropractic

patients were all in long term care on
a wellness basis. Their immune func

22.

mid. For example, you can in
crease the life of a razor blade by

four times stronger than the sick! And
this increase occurred regardless of
age. With ongoing chiropractic care,

keeping it stored inside a simple
plastic pyramid. If you don't
believe me, try this simple ex

the immune system does not deterio
rate, as in other groups.
21.

periment. After you use your

razor, remove the blade, wash it
in warm water and then dry the

From an ad for past life drawings
drawings by a psychic of the way we
looked in ourpast lives:

blade off. Finally, place it inside
or under a small pyramid
shaped container. I think you

Since I've been doing Past Life Draw
ings and Readings for people, I'm
often amazed at how relevant the
information is in their present lives.

will be surprised at how long
the blade retains its sharpness.
23.

marvelous feat, consider the
following explanation by

sands of incarnations, I've found that
there are usually three main past lives
which are influencing our present hves

G. Patrick Flannigen, self
proclaimed pyramid power

the most.

expert: The shape of the pyra

One woman that I did drawings for

mid acts as a sort oflens or
focus for the transmission of

had a past life in India as a young male
who rode and trained elephants to lift

bio-cosmic energy.

logs and move stones to build a tem
completed, the man decided to spend

the rest of his life meditating in the

Ifyou are wondering how pyra
mids manage to accomplish this

Even though we may have had thou

ple.Years later when the temple -was

Many strange and wonderful
things are attributed to the
mysterious power of the pyra

tion was measured to be two times
stronger than the healthy people, and

A recent study has shown that,

on average, a graduate of an ivy

league college will make more

temple. The woman revealed that she

money over the course of his or

had been doing Eastern meditation for

her career than a graduate of

many years and she also had a large

any other college. Moreover, a
graduate of an east coast college

ceramic elephant lamp, elephant

FALLACIES IN THE NAME OF SCIENCE

will make more than a graduate
of a midwestern, southern, or
western college. It seems clear
that if you want to make it

financially, you ought to try to
get into an ivy league school

and, if you can't get in, at least

go to college on the east coast.
25.

Thefollowing newspaper story
appeared under the headline, "Gyro
scope Test Possibly Defies Grovity:"

Japanese scientists have reported that
small gyroscopes lose weight when
spun under certain conditions, appar
ently in defiance of gravity. If proved
correct, the finding would mark a
stunning scientific advance, but ex
perts said they doubted that it would
survive intense scrutiny.
A systematic way to negate gravita

tion, the attraction between all masses

and particles of matter in the universe,
has eluded scientists since the princi
ples of the force were first elucidated
by Issac Newton in the 17th century.
The anti-gravity work is reported in
the Dec. 18, 1989 issue of Physical

results are presented with scientific
understatement. The authors do not
claim to have defied gravity, but simply
say their results "cannot be explained
by the usual theories."
"It's an astounding claim," said
Robert L. Park, a professor of

director of the Washington office of
the American Physical Society, which
publishes Physical Review Letters. "It
would be revolutionary if true. But it's
almost certainly wrong. Almost all
extraordinary claims are wrong."
The experiment looked at weight
changes in spinning gyroscopes whose
rotors weighed 140 and 176 grams, or
5 and 6.3 ounces. When the gyro

scopes were spun clockwise, as viewed
from above, the researchers found no
change in their weight. But when
spun counterclockwise, they appeared

to lose weight. 12
26.

programs on conunercial televi
sion tend to be lower achievers
established that performance on
standardized tests varies in in
verse proportion to the amount
of television a child under the

articles are rigorously reviewed by
other scientists before being accepted

age of12 watches. The more
television of this sort a child

for publication, and it rejects far more
than it accepts.
Experts who have seen the report

lapsed under close examination.
The work was performed by
Hideo Hayasaka and Sakae Takeuchi
of the engineering faculty at Tohoku

It seems that children who spend
more time watching popular

in school. Several studies have

no obvious sources of experimental
error, but they cautioned that other
seemingly reliable reports have col

physics

at the University of Maryland who is

Review Letters, which is regarded
experts as one of the world's leading
journals of physics and allied fields. Its

said that it seemed to be based on
sound research and appeared to have

133

27.

watches, the lower are his or her
scores likely to be.
Nostradamus, a sixteenth century

French physician, is said to have
predicted with great aauracy things
that occu"ed long
his death.

tifter

Nostradamus' prophedes were writ
ten as short poems, called quatrains.
The following are said toforetell

recent events·

University in Sendai,Japan.
Unlike the exaggerated claims

One burned, not dead, but apoplectical,

made for low-temperature or"cold"

Shall be found to have eaten up his

nuclear fusion this year, the current

hands,

134

CHAPTER SIX

When the city shall damn the hereti
cal man,
Who as they thought had changed
their laws.
To the great empire, quite another
shall come,
Being distant from goodness and
happiness,
Governed by one of base parentage
The kingdom shall fall, a great
unhappiness.
A prominent Nostradamus
scholar gives the following in
terpretations.The first quatrain
refers to President Nixon's
downfall and the Watergate
scandal. The second is said to
predict the rise and dominance
of communism and the subse
quent subjugation of the West
ern democracies. 13
28.

From aflyer headed "Does Sunday
School Make a Dijference?":

MaxJuken lived in NewYork. He did
not believe in religious training. He
refused to take his children to church,
even when they asked to go. He has
had 1,062 descendants; 300 were sent
co prison for an average term of
13 years; 190 were prostitutes;
680 were admitted alcoholics. His
family, thus far, has cost the state in
excess of$420,000. They made no
contribution to society.
Jonathan Edwards lived in the same
state, at the same time as the Jukes. He
saw that his children were in church
every Sunday. He had 929 descen
dants, of these 430 were ministers;
86 became college professors;
13 became university presidents;
75 authored good books; five were
elected to the United States Congress,
and two to the Senate. One was Vice
President of his nation. His family
never cost the state one cent, but has
contributed to the life of plenty in this
land today.

29.

Some dentists and "alternative"
medical practitioners believe we
are being poisoned by mercury
contained in our dental fillings.
When we chew, minute quanti
ties of mercury are released from
our fillings and are ingested into
the body. Over time, the
amount of mercury in the body
is liable to reach toxic propor
tions. A flyer on mercury toxic
ity and dental fillings gives the
following as symptoms related
to mercury poisoning and sug
gest that if you have more than
a few, you ought to carefully
consider having you mercury
amalgam filling removed:

Anxiety

Apathy

Confusion

Depression

Emotional instability

Fits of anger

Irritability

Nervousness

Nightmares

Tension

High blood pressure

Low blood
pressure

Chronic headaches

Dizziness

Muscle twitches

Ringing in

Colds hands or feet

Decreased
sexual activity

Leg cramps

Pain in joints

Weight loss

Fatigue

Drowsiness

Lack of energy

Allergies

Over-sleeping

Bad breath

Bleeding gums

Acne

Rough skin

Skin flushes
30.

Unexplained
skin rashes

Dear Ann Landers: In a recent
column, you recounted how
Reader's Digest tested the hon
esty of Europeans by dropping
wallets in various cities. You

FALLACIES JN THE NAME OF SCIENCE

wondered how the United States
would fare ifput to the same
test.Well, we can tell you.WE
did some U.S. testing and printed
the results in the December 1995
issue. Here's a copy.

Public Relations Associate

Director, Reader� Digest

Dear Lesta: Many thanks for the assist.
I'm sure my readers will find the re
sults interesting. I certainly did. Read
if you're wondering how your city

stacked up (I thought Chicago would
have done very well), you might not
find the answer here. The experiment
was

Of the 120 wallets dropped,
80 were returned with all the money
intact. Seattle turned out to be the
most honest city. Nine of the ten
wallets dropped in Seatde were re
turned with the $50 inside.
Three smaller cities turned out to be

Lesta Cordil

ers,

135

done in only 12 cities. Here's how

it was set up·
One hundred and twenty wallets
containing $50 each were dropped on

the streets and in the shopping malls,
restaurants, gas stations and office
buildings in a number of U.S. cities. In
each wallet was a name, local address,
phone number, family pictures and

coupons, as well as the cash. A Reader's

Digest reporter followed on the heels

of the wallet-croppers, and this is what
his research revealed.

very near the top for honesty; Meadville,
Pa.; Concord, N.H.; and Cheyenne,
\Vyo. In each of these cities eight wallets
were returned and two were not.
St. Louis came in next--of the ten
wallets dropped, seven were returned
and three were kept. The suburbs of
Boston ties with St. Louis. The suburbs
of Los Angeles were not quite as hon
est. Six wallets were returned, four
were kept. Four cities-Las Vegas;
Dayton, Ohio; Atlanta; and the suburbs
of Houston - shared the poorest
records. Five wallets were returned
and five were kept.
Small towns scored 80 percent
returns and proved to be more honest
than larger cities, with the exception
of Seattle. Women, it turned out, were
more honest than men - 72 percent to
62 percent.Young people posted a

67 percent return rate - the same as

the overall average. 14

A S O L U T I O N TO E X E R C I S E 1
The suggestion in this passage is that

else. Now, even ifsuch a correlation could

there is some sort of causal connection

be established, serious questions could be

between an interest in science and an

raised about its significance. There are a

interest in music. Thefacts about Einstein

number of ways ofexplaining such a cor�

and Newton are most likely meant to

relation short ofsuggesting that an inter�

though the passage does not come right

ested in a career in science.

imply a correlation between the two,

out and say that a higher percentage of

est in music causes one to bewme inter�

The real problem with the passage,

scientists than nonscientists are interested

however, is that it involves the fallacy

in music. Otherwise there would be no

have called "FalseAnomalies. "� are told

reason to believe that a child� interest in
music would lead him or her to pursue a

career in science rather than something

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A Begginers Guide To Scientific Method

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