Critical Thinking: Chapter 4

Credibility
Credibility

Are you gullible?
Credibility


Are you gullible?
Do you get taken advantaged of?
Credibility

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
Are you gullible?
Do you get taken advantaged of?
Do people think you are naïve?
Credibility




Are you gullible?
Do you get taken advantaged of?
Do people think you are naïve?
Are you trusting? Is there anything
wrong with being trusting?
Credibility



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
Are you gullible?
Do you get taken advantaged of?
Do people think you are naïve?
Are you trusting? Is there anything
wrong with being trusting?
Are you a skeptic?
Credibility



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
Are you gullible?
Do you get taken advantaged of?
Do people think you are naïve?
Are you trusting? Is there anything
wrong with being trusting?
Are you a skeptic?
These are the type of questions we are
going to look at in this chapter.
Credibility

Is a claim credible or not?

Basically credibility comes in degrees.
Credibility

It is very difficult to judge the credibility
of a person just by looking at them.
Credibility
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
1st general principle: “It is reasonable to
be suspicious if a claim either lacks
credibility inherently or comes from a
source that lacks credibility.”
So there are two issues here: When
does a claim lack credibility and when
does a source lack credibility?
Credibility

2nd general principle: “A claim lacks
inherent credibility to the extent it
conflicts with what we have observed or
what we think we know (our background
information), or with other credible
claims.
Assessing the Contents of the
Claim

Does the claim conflict with our
personal observations?
Four Issues with observations:


The problem is that we are aware that
observation is a trick business. There
are four issues with observations:
1. Observations depend on the
conditions under which they are made.
Four Issues with observations:


1. Observations depend on the
conditions under which they are made.
For Example: Perhaps the lighting is
poor or the room is noisy; perhaps we
are distracted, emotionally upset, or
mentally fatigued.
Four Issues with observations:
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
2. The power of observation can differ
with people’s expertise and experience.
For Example: Some people have
special training or experience that
makes them better observers.
Four Issues with observations:
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3. Expectations often influence
observation.
For Example: We overlook many of the
mean and selfish actions of the people
we love. By contrast, people we detest
can hardly do anything that we don’t
perceive as mean and selfish.
Four Issues with observations:
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4. An observation made in the past
suffers from the same dangers of
unreliability as memory in general.
Critical thinkers are always alert to the
possibility that what they remember
having observed may not be what they
did observe!
Does the claim conflict with
our background information?

Background information includes all the
general and specific facts we have
learned through our lives. Three points
to remember:
Does the claim conflict with
our background information?


Background information includes all the
general and specific facts we have
learned through our lives. Three points
to remember:
1. Together with direct observation,
background information forms the
ground against which to pose any new
claim.
Does the claim conflict with
our background information?

Background information is that immense
body of justified beliefs that consists of
facts we learn from our own direct
observation and facts we learn from
others.
Background information:

Much of our background information is
well confirmed by a variety of sources.
Factual claims that conflict with this
store of information are usually quite
properly dismissed.
Background information:

For Example: We immediately reject the
claim “Palm trees grow in abundance
near the North Pole,” even though we
are not in a position to confirm or
disprove the statement by direct
observation.
Does the claim conflict with
our background information?
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
Three points to remember:
1. Together with direct observation,
background information forms the
ground against which to pose any new
claim.
Does the claim conflict with
our background information?
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Three points to remember:
2. When two claims conflict, the burden
of proof lies on the one with less initial
plausibility. We have reason to be more
skeptical.
Example: A claim that two people swam
a mile in cold water, one person is 21
and the other person is 91.
Does the claim conflict with
our background information?
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3. It is important to remember that we don’t
have all the background information we need
and some of our information may be false.
The single most effective means of increasing
your ability as a critical thinker, regardless of
the subject, is to increase what you know.
Assessing the credibility of
sources

The guiding principle in evaluating
claims requires that they come from
credible sources. The credibility of
people is usually a matter of their
knowledge on one hand, and their
truthfulness, accuracy, and objectivity
on the other. Seven points:
Sharpening and Leveling

The reports people give one another are
very frequently subject to innocent
sharpening and leveling--exaggerating
what the speaker thinks is the main
point and dropping out or deemphasizing details that seem
unimportant. The result can be a
distortion of the story.
Assessing the credibility of
sources: 3 points
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
1. Be wary of eyewitness accounts.
Untrained observers are more likely to
exaggerate their observations.
Example: Several people seeing the
same event will often describe it
differently!
Assessing the credibility of
sources: 3 points
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
2. How we feel about an experience
colors our ability to discern objectively.
Example: if we really like a band, it may
be difficult to give an objective review of
their latest album.
Assessing the credibility of
sources: 3 points
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3. Look for expert knowledge.
Example: Look for education, training,
experience, accomplishments,
reputation, and titles.
Cautions about experts: Just because
someone is an expert in one thing does
not make them an expert in all things!
The news media and the
internet

Our abundance of sources of
information is a good thing, but it can be
complicated when trying to figure out
what we can trust and believe. Five
points:
The news media and the
internet: 5 points


1. Most talk shows have a specific
political agenda.
Look for documentation of sources.
The news media and the
internet: 5 points
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2. The traditional news media has to be
watched for both length and depth of
coverage.
The accessibility of reliable reports also
restricts coverage because
governments, corporations, and
individuals often withhold information.
The news media and the
internet: 5 points
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3. Reporters are, for the most part,
given the news.
Be careful over having too romantic a
view of “the investigative reporter.” Time
and money often limit the ability of a
reporter to investigate.
The news media and the
internet: 5 points
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4. The media is a business.
Follow the money! Good and bad sides
to this. Good side: independent of
government. Bad side: the need to
make a profit.
The news media and the
internet: 5 points
5. The internet has to be treated like the
media: Anyone can put up a web page
saying anything, so check for credibility.
Sites that represent institutions and
universities tend to be more objective
and reliable than a site with no backing
organization, but it is always a good
idea to use your critical thinking skills!
Advertising
“Advertising is the science of arresting
human intelligence long enough to get
money from it.”
Stephen Leacock
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Advertising

Advertising does not only sell consumer
goods. Advertising is used to sell
candidates, ideas, and as we have seen
recently, wars.
Advertising
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How does advertising work?
It acts by creating desires, and it uses
every persuasive technique available to
excite those desires.
Advertising

The usual reasons found in an
advertisement are vague, ambiguous,
misleading, or exaggerated. In doing
this we often find ourselves needing
something we might not have known
existed before!
Advertising
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So what is a good advertisement?

Basically a good ad simply lets you
know that something you already want
is available somewhere at a price you
can afford.
Exercises

Assess each of the following claims as probably true,
probably false, as requiring further documentation before
judgment, or as a claim that cannot properly be evaluated.
Consider both the nature of the claim and the source.


“In the early 1800s, bears were a nuisance to settlers
in upstate New York.”
—Smithsonian
Exercises

Assess each of the following claims as probably true,
probably false, as requiring further documentation before
judgment, or as a claim that cannot properly be evaluated.
Consider both the nature of the claim and the source.

“In the early 1800s, bears were a nuisance to settlers
in upstate New York.”
—Smithsonian
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Probably true

Exercises

Assess each of the following claims as probably true,
probably false, as requiring further documentation before
judgment, or as a claim that cannot properly be evaluated.
Consider both the nature of the claim and the source.
 NO CHOLESTEROL!

—Label on Crisco Corn Oil
Exercises

Assess each of the following claims as probably true,
probably false, as requiring further documentation before
judgment, or as a claim that cannot properly be evaluated.
Consider both the nature of the claim and the source.
 NO CHOLESTEROL!

—Label on Crisco Corn Oil

Probably true. Vegetable oils do not contain
cholesterol, and even if you didn’t know that, such
claims made by national brands are usually true
(despite several famous exceptions).
Exercises

Assess each of the following claims as probably true,
probably false, as requiring further documentation before
judgment, or as a claim that cannot properly be evaluated.
Consider both the nature of the claim and the source.
 “Mezzo-soprano Frederica von Stade’s two little
girls always tried to keep her from singing in church
because, they said, every time she did, everyone
would turn around and stare at her.”

—Joseph McLellan, in the Washington Post
Exercises

Assess each of the following claims as probably true,
probably false, as requiring further documentation before
judgment, or as a claim that cannot properly be evaluated.
Consider both the nature of the claim and the source.
 “Mezzo-soprano Frederica von Stade’s two little
girls always tried to keep her from singing in church
because, they said, every time she did, everyone
would turn around and stare at her.”

—Joseph McLellan, in the Washington Post

Probably true
Exercises

Assess each of the following claims as probably true,
probably false, as requiring further documentation before
judgment, or as a claim that cannot properly be evaluated.
Consider both the nature of the claim and the source.
 “In the near future look for floods in Britain which
will culminate in the flooding of Parliament.”

—A prediction made by Maitreya Swami,
“The World Teacher,” in the News Release of the
Tara Center, N. Hollywood, Calif.
Exercises

Assess each of the following claims as probably true, probably false, as
requiring further documentation before judgment, or as a claim that
cannot properly be evaluated. Consider both the nature of the claim
and the source.



“In the near future look for floods in Britain which will
culminate in the flooding of Parliament.”
—A prediction made by Maitreya Swami, “The World
Teacher,” in the News Release of the Tara Center, N.
Hollywood, Calif.
Probably false. I won’t get into the philosophical
difficulties involved in attaching truth values to future
contingent events.
Exercises

Assess each of the following claims as probably true,
probably false, as requiring further documentation before
judgment, or as a claim that cannot properly be evaluated.
Consider both the nature of the claim and the source.
 “Smoking more than triples the likelihood of
premature facial wrinkling.”

—Dr. Donald Kadunce, lead author of a group
of University of Utah scientists, reporting in Annals
of Internal Medicine
Exercises

Assess each of the following claims as probably true, probably false, as
requiring further documentation before judgment, or as a claim that
cannot properly be evaluated. Consider both the nature of the claim
and the source.



“Smoking more than triples the likelihood of premature facial
wrinkling.”
—Dr. Donald Kadunce, lead author of a group of
University of Utah scientists, reporting in Annals of Internal
Medicine
Probably true, but you’d probably want to have a look
at the study to see, among other things, how the degree of
wrinkling is ascertained.
Exercises

Assess each of the following claims as probably true, probably false, as
requiring further documentation before judgment, or as a claim that
cannot properly be evaluated. Consider both the nature of the claim
and the source.

University student to professor: “I’m sorry I missed
the test on Thursday, Dr. Aarsack. My grandmother
unexpectedly died, and I had to go home.”
Exercises

Assess each of the following claims as probably true, probably false, as
requiring further documentation before judgment, or as a claim that
cannot properly be evaluated. Consider both the nature of the claim
and the source.


University student to professor: “I’m sorry I missed
the test on Thursday, Dr. Aarsack. My grandmother
unexpectedly died, and I had to go home.”
Requires further documentation.
Exercises

Assess each of the following claims as probably true, probably false, as
requiring further documentation before judgment, or as a claim that
cannot properly be evaluated. Consider both the nature of the claim
and the source.


“A few years ago AT&T did two surveys showing
that technically trained persons did not achieve as
many top managerial jobs in the company as liberal
arts graduates did.”
—New York Times
Exercises
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“A few years ago AT&T did two surveys showing
that technically trained persons did not achieve as
many top managerial jobs in the company as liberal
arts graduates did.”
—New York Times
Probably true. It is often risky to accept what
secondhand reports say about what surveys “show,”
but the New York Times is a credible source. This
claim is probably true. Note, however, the vagueness
of “did not achieve” and “top managerial jobs.”
Exercises
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
Q: Did Marilyn Monroe keep a diary about her
relationships with John and Robert Kennedy?
A: No.
—Walter Scott’s Personality Parade, Parade
Exercises
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
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
Q: Did Marilyn Monroe keep a diary about her
relationships with John and Robert Kennedy?
A: No.
—Walter Scott’s Personality Parade, Parade
Requires further documentation. Scott’s
question-and-answer column is probably a
reasonably reliable source of information about the
questions asked. Secret diaries are always a
possibility, of course.
Exercises

Comment from an acquaintance: “I saw Bigfoot
with my own eyes! It was huge!”
Exercises

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Comment from an acquaintance: “I saw Bigfoot
with my own eyes! It was huge!”
Probably false; observational error is more
likely than incorrect background information.
Exercises


“Every day 5,000 Americans try cocaine for
the first time—a total of 22 million so far—
according to estimates by the National Institute on
Drug Abuse. About five million people are believed
to be using the drug at least once a month, and they
are administering it to themselves in increasingly
destructive ways.”
—James Lieber, in the Atlantic
Exercises
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
“Every day 5,000 Americans try cocaine for the first
time—a total of 22 million so far—according to estimates by
the National Institute on Drug Abuse. About five million
people are believed to be using the drug at least once a month,
and they are administering it to themselves in increasingly
destructive ways.”
—James Lieber, in the Atlantic
Requires further documentation. I don’t know much
about the National Institute on Drug Abuse, but I have found
the Atlantic to be pretty reliable in factual matters. Notice that
no exact figures are claimed; the first is explicitly said to be an
estimate, and the phrases “about” and “believed to be”
qualify the second. I would expect these claims to be close to
the truth.
Exercises

Reported after a debate between Al Gore and Bill
Bradley, who were running for the Democratic
nomination for the presidency in 2000: “Lt. Gov. [of
California] Cruz Bustamante, a Gore supporter,
declared his candidate the ‘winner’ in the debate,
saying he’d made his case more strongly.”
Exercises


Reported after a debate between Al Gore and Bill
Bradley, who were running for the Democratic
nomination for the presidency in 2000: “Lt. Gov. [of
California] Cruz Bustamante, a Gore supporter,
declared his candidate the ‘winner’ in the debate,
saying he’d made his case more strongly.”
Cannot properly be evaluated. Absolutely
unreliable for reasons of bias. We’d reserve
judgment.
Exercises


“Do you feel insecure? Or are you confident about
your position in life? According to Dr. Ian Cameron,
how and where you stand in an elevator will reveal
the answers to these questions.”
—Reported in the National Examiner. Dr.
Cameron is described in the article as “a noted
scientist and researcher.”
Exercises



“Do you feel insecure? Or are you confident about your
position in life? According to Dr. Ian Cameron, how and where
you stand in an elevator will reveal the answers to these
questions.”
—Reported in the National Examiner. Dr. Cameron is
described in the article as “a noted scientist and researcher.”
Cannot properly be evaluated. Is this remark the
conclusion of a study? A speculation on the part of Dr.
Cameron? Who is Dr. Cameron, anyway? I am suspicious
because so little information is given about him. More
important, the claim runs counter to my background
information.
Exercises


“[Atmospheric nuclear] tests do not seriously
endanger either present or future generations.”
—Edward Teller, physicist, one of the
“fathers” of the atomic bomb, 1958
Exercises



“[Atmospheric nuclear] tests do not seriously
endanger either present or future generations.”
—Edward Teller, physicist, one of the
“fathers” of the atomic bomb, 1958
Requires further documentation. I’d expect this
kind of claim, coming from such a source, to be
trustworthy. That it turned out to be false probably
shows either that Teller was biased or that there was
not enough information on the effects of
atmospheric tests in 1958, or both.
Exercises

Discuss whose opinion on the foreign
policy of the current administration is
more credible.
a.
A former U.S. president of the
same political party as the current president
b. A former U.S. president not of the
same political party as the current president



For the following, discuss which source you’d trust
more, and give at least one reason why.
Exercises

Discuss whose opinion on the foreign
policy of the current administration is
more credible.
a.
A Ph.D. in political science whose
speciality is U.S. foreign policy
b. The chairman of the U.S. Senate
Foreign Relations Committee



For the following, discuss which source you’d trust
more, and give at least one reason why.
Exercises



Discuss whose opinion on the condition of
the tires on your car is more credible.
a.
A salesperson at Goodyear
b. A mechanic at a garage certified by
the American Automobile Association
Exercises



Issue: A proposal for legislation regarding
automobile insurance rates is on the ballot.
Discuss whose opinion on the benefits for
consumers is more credible.
a.
A spokesperson for the insurance
industry
b. Ralph Nader
Exercises



Did life evolve, or was it created? Discuss
whose opinion is the more credible.
a.
A biologist
b. A minister
Exercises



What percentage of American high school
students have smoked marijuana?
a.
USA Today
b. Americans for Legalized
Marijuana (ALM)
Exercises



How many homicides involve the use of a
stolen firearm?
a.
A Democratic U.S. senator
b. A Republican U.S. senator
Exercises



Which of two current movies you would be
more apt to like?
a.
One recommended by a movie
critic whose opinions you enjoy listening to
b. One recommended by a friend
Exercises



What is the best weight-lifting regimen to
follow?
a.
Arnold Schwarzenegger
b. Roseanne
Exercises

Discuss the credibility and authority of each individual or group listed
with regard to the questions or issues posed. Whom would you trust as
most reliable on each subject?






You are thinking of insulating your attic and need advice
relative to how much insulation you should install.
a.
b.
c.
company
d.
e.
A company that sells insulation but does not install it
A company that sells and installs insulation
An energy consultant from your local gas and electric
Consumer Reports
A friend who has recently had his attic insulated
Exercises





a.
b.
c.
company
d.
e.

A company that sells insulation but does not install it
A company that sells and installs insulation
An energy consultant from your local gas and electric
Consumer Reports
A friend who has recently had his attic insulated
I think you are most likely to get the best information from (d),
with (c) a close second; (a) and (b) are about equal in
credibility, and (e)’s ranking depends on where he got his
information.
Exercises

You’ve purchased a wood-burning stove. You are uncertain,
however, what kind of wood to burn in it. You’ve heard that
some produce more smoke, some are more likely to contribute
to chimney fires, some burn hotter than others, and so forth.





a.
The dealer from whom you purchased the stove
b.
A friend of yours who has used a wood-burning
stove for years
c.
Another friend who sells firewood
d.
A U.S. Department of Agriculture publication,
“Comparative Properties of Fuelwood”
e.
A professor of environmental horticulture at a state
university
Exercises

You’ve purchased a wood-burning stove. You are uncertain,
however, what kind of wood to burn in it. You’ve heard that
some produce more smoke, some are more likely to contribute
to chimney fires, some burn hotter than others, and so forth.






a.
The dealer from whom you purchased the stove
b.
A friend of yours who has used a wood-burning
stove for years
c.
Another friend who sells firewood
d.
A U.S. Department of Agriculture publication,
“Comparative Properties of Fuelwood”
e.
A professor of environmental horticulture at a state
university
All these sources are credible, but (d) should rank first, and,
most likely, (a) should rank last.
Exercises






A number of your friends have taken up jogging, and you
wonder whether your taking it up might have genuine health
benefits for you.
a.
Your family physician
b.
A magazine for runners
c.
A friend who teaches physical education
in high school
d.
The author of a best-selling book on
sports medicine
e.
A friend who is president of a local
runners club
Exercises





a.
b.
c.
d.
e.

Your family physician
A magazine for runners
A friend who teaches physical education in high school
The author of a best-selling book on sports medicine
A friend who is president of a local runners club
(b), (c), and (e) might tend to be promoters of jogging, so I’d
be mildly skeptical of any pro-jogging claims they might make
(but less skeptical of any liabilities of jogging that they might
mention). I’d find (a) a more credible source, although many
general practitioners may not have the time to keep up on such
specialized areas. The best potential source is probably (d),
although I’d be cautious unless I knew something about the
author; he or she might also tend to exaggerate either the
benefits—or the risks—of jogging.
Exercises






You are looking at a sailboat that you’re considering buying,
but you’ve never owned one before and don’t know whether
you should buy this one.
a.
The boat salesman at the marina that
owns the boat
b.
A boat salesman from another marina
c.
A friend who has owned several similar
boats
d.
A buyer’s guide published by a sailing
magazine
e.
Your own appraisal
Exercises
For the following, discuss which source you’d trust more, and give at
least one reason why. You may want to add to or otherwise modify our
lists of sources. And do keep in mind that we are glad our livelihoods
do not depend on a general consensus on our rankings.






Issue: Should lawyers allow their clients to lie?
a.
b.
c.
d.
e.
The U.S. Supreme Court
A law school professor
A political science professor
The American Bar Association
A practicing defense attorney
Exercises

This question is not so straightforward and simple as it might
seem. For instance, has a client who is forced to tell the truth
in effect been denied an effective defense? Can one even know
that one’s client has lied? In forming my opinion on the
subject, I’d be most influenced by the reasoning of the person
who seemed to have the best grasp of the various subsidiary
issues involved. In other words, in this case it’s the reasoning
rather than the credentials of the reasoner that will carry the
most weight. (I would not anticipate that any of the sources
listed would be deficient in powers of reasoning.)
Exercises

Issue: In the O. J. Simpson murder case, did the
judge rule correctly in admitting evidence that was
obtained at Simpson’s house before a search warrant
was issued?



b.
County
c.
a.
A well-known defense attorney who
heads the American Trial Lawyers
Association
The former district attorney for Los Angeles
A retired judge on the U.S. Court of Appeals
Exercises


a.A well-known defense attorney who heads the
American Trial Lawyers Association
The former district attorney for Los Angeles
b.
County
c.
A retired judge on the U.S. Court of Appeals
 I put (c) way out in front, and the other two equally
biased on opposite sides of the issue.
Exercises

Issue: Does violence on television contribute to
violent behavior on the part of young viewers?




a.
The president of the National Association of
Broadcasters
b.
The president of an organization called
“Parents Against TV Violence”
c.
A university sociologist
d.
Regular panel members of a program such as
“Crossfire” or “The McLaughlin Group”
Exercises





a.
The president of the National Association of
Broadcasters
b.
The president of an organization called “Parents
Against TV Violence”
c.
A university sociologist
d.
Regular panel members of a program such as
“Crossfire” or “The McLaughlin Group”
I rank (c) first, followed by (b), who would be ahead of (a). I
do know what side (b) is on from the outset, of course, but
that’s somewhat different from having a vested interest in one
side of the issue in the way that (a) does. I find most of the
people like those mentioned in (d) to be full of hot air on most
subjects.
Exercises

Issue: Do mountain bicycles cause ecological
damage when ridden on hiking trails?





a.
An environmental scientist at the Harvard
School of Public Health
b.
The chair of the Sierra Club task force for
determining club policy on the wilderness use of mountain
bicycles
c.
A spokesperson for a bicycle manufacturer
d.
A park ranger from a state park where
mountain bicycles have been permitted on hiking trails
e.
A representative of the Washington Mountain
Bike Riders’ Association
Exercises





a.
An environmental scientist at the Harvard
School of Public Health
b.
The chair of the Sierra Club task force for
determining club policy on the wilderness use of mountain
bicycles
c.
A spokesperson for a bicycle manufacturer
d.
A park ranger from a state park where
mountain bicycles have been permitted on hiking trails
e.
A representative of the Washington Mountain
Bike Riders’ Association

(c) = (a)
My ranking: (d) = (b) first, then (e) =
Exercises





Issue: Are schools of business turning out too
many ill-prepared M.B.A. graduates?
a.
The dean of the school of business at
the University of Chicago
b.
The president of the Hewlett-Packard
Corporation
c.
An editorial in the Wall Street Journal
d.
A recent graduate with an M.B.A.
Exercises






Issue: Are schools of business turning out too
many ill-prepared M.B.A. graduates?
a.
The dean of the school of business at
the University of Chicago
b.
The president of the Hewlett-Packard
Corporation
c.
An editorial in the Wall Street Journal
d.
A recent graduate with an M.B.A.
My ranking: (c), (b), (a), (d)
Exercises






Issue: What levels of mercury and other metals in fish are high
enough to make their consumption hazardous to humans?
a.
An article in a journal called Diet and
Health, published for vegetarians
b.
A commercial fisherman
c.
A family medical doctor
d.
A spokeswoman for the National
Institutes of Health
e.
A toxicologist who works for the Los
Angeles coroner’s office
Exercises






a.
An article in a journal called Diet and Health,
published for vegetarians
b.
A commercial fisherman
c.
A family medical doctor
d.
A spokeswoman for the National Institutes of
Health
e.
A toxicologist who works for the Los Angeles
coroner’s office
My ranking: (d), then a substantial gap, then
(e) and (c), another gap, then (a), (b)
Exercises
Issue: Were there unjustifiable cost overruns in the
construction of ships made for the U.S. Navy by
Lytton Industries?
a.
The chair of the Senate Armed Services
Committee
b.
The accounting director for Lytton
c.
The Navy Chief of Staff
d.
The OMB (Office of Management and
Budget)
e.
An article in The Progressive (a left-of-center
political journal)






Exercises
a.





The chair of the Senate Armed Services Committee
b.
The accounting director for Lytton
c.
The Navy Chief of Staff
d.
The OMB (Office of Management and
Budget)
e.
An article in The Progressive (a left-of-center
political journal)
Our ranking: (d), (a), depending on the
individual’s politics, then (c) = (e), (b)
Exercises

State whether the following are true or
false.

You should assume that the claims made by others
are false unless you have some specific reason to
believe otherwise.
Exercises

State whether the following are true or
false.


You should assume that the claims made by others
are false unless you have some specific reason to
believe otherwise.
False
Exercises

State whether the following are true or
false.

If you have reason to believe that an expert is
biased, you should reject that expert’s claim as false.
Exercises

State whether the following are true or
false.


If you have reason to believe that an expert is
biased, you should reject that expert’s claim as false.
False (The possibility of bias is occasion to
question his or her claims, to suspend judgment on
them, to give more weight to alternative claims from
unbiased experts, and so on—this is different from
rejecting the original expert’s claims as false.)
Exercises

State whether the following are true or
false.

Except when we have the means to record our
observations immediately, they are no better than
our memories happen to be.
Exercises

State whether the following are true or
false.


Except when we have the means to record our
observations immediately, they are no better than
our memories happen to be.
True
Exercises

State whether the following are true or
false.

Fallible or not, our firsthand observations are still
the best source of information we have.
Exercises

State whether the following are true or
false.


Fallible or not, our firsthand observations are still
the best source of information we have.
True
Exercises

State whether the following are true or
false.

Reference works such as dictionaries are utterly
reliable sources of information—otherwise they
wouldn’t be reference works.
Exercises

State whether the following are true or
false.


Reference works such as dictionaries are utterly
reliable sources of information—otherwise they
wouldn’t be reference works.
False
Exercises

State whether the following are true or
false.

A surprising claim, one that seems to conflict with
our background knowledge, requires a more credible
source than one that is not surprising in this way.
Exercises

State whether the following are true or
false.


A surprising claim, one that seems to conflict with
our background knowledge, requires a more credible
source than one that is not surprising in this way.
True
Exercises

State whether the following are true or
false.

Factual claims put forth by experts about subjects
outside their fields are not automatically more
acceptable than claims put forth by nonexperts.
Exercises

State whether the following are true or
false.


Factual claims put forth by experts about subjects
outside their fields are not automatically more
acceptable than claims put forth by nonexperts.
True
Exercises

State whether the following are true or
false.

You are rationally justified in accepting the view of
the majority of experts in a given subject even if this
view turns out later to have been incorrect.
Exercises

State whether the following are true or
false.


You are rationally justified in accepting the view of
the majority of experts in a given subject even if this
view turns out later to have been incorrect.
True