Introduction Evaluating arguments When is an argument a good one? When is it reasonable to accept premises? Refuting arguments

1. Evaluating
Arguments &
Truth Claims
PRESENTED
TO: MA’AM
RABIA

2. Jens
Martensson
Presentation
Plan
• Introduction
• Evaluating arguments
• When an argument a
good one?
• When is it reasonable
to accept a premises?
• Refuting arguments
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3. Jens
Martensson
INTRODUCTION
What is an argument?
Arguments are composed of one or more premises
and a conclusion.
• Premises are statements in an argument offered
as evidence or reasons what we should accept
another statement, the conclusion.
• The conclusion is the statement in an argument
that the premises are intended to prove or
support.
• An argument, accordingly, is a group
of statements, one or more of which (called
the premises) are intended to prove or
support another statement (called the
conclusion). 3

4. Jens
Martensson
INTRODUCTION
(CONT.)
The three goals of critical
argumentation are to identify,
analyze, and evaluate arguments.
• Primarily, argument has two
purposes:
 Argument is used to change
people's points of view or
persuade them to accept new
points of view;
 And argument is used to
persuade people to a particular
action or new behavior.
• Argument teaches us how to
evaluate conflicting claims and
judge evidence and methods
of investigation.
• It also helps us learn to clarify our
thoughts and articulate them
honestly and accurately and to
consider the ideas of others in a
respectful and critical manner.
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5. Jens
Martensson
EXAMPLE
Claim:
• Smoking cigarettes is injurious to health.
Support:
• Tobacco kills over 163,600 people each year in
Pakistan. Almost 31,000 of these deaths are due to
exposure to secondhand smoke.
• Tobacco causes about 16.0% of all male deaths and
4.9% of female deaths. Overall, 10.9% of all deaths are
caused by tobacco.
• Tobacco causes 66.5% of all deaths from tracheal,
bronchus, and lung cancer, 53.2% of deaths from
chronic obstructive pulmonary disease, 21.9% of
deaths from ischemic heart disease, 15.2% of deaths
from diabetes mellitus, and 16.8% of deaths from
stroke.
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6. Jens
Martensson
EXAMPLE
Claim:
• Junk food is bad for your health.
Support:
• Eating too much junk food is linked to
serious health problems.
• Eating junk food on a regular basis
can lead to an increased risk of
obesity and chronic diseases
like cardiovascular disease, type 2
diabetes, non-alcoholic fatty liver
disease and some cancers.
• It can affect the brain function and
slow down the ability of learning new
skills.

7. Jens
Martensson
TRUTH CLAIMS 7
• In order to be in a position to judge whether a given statement is true or false it is first necessary
to have a notion of what it means for a statement to be true.
• This is to say that in order to properly assess truth claims we must have at least a working account
of what truth is.
• Although we generally get by with intuitive notions of truth, for the critical assessment of
arguments we really need a more precise account.
• In religion, a truth claim is an assertion that the belief system holds to be true; however, from the
existence of an assertion that the belief system holds to be true, it does not follow that the
assertion is true.
• For example, a truth claim in Judaism is that only one God exists. Conflicting truth claims between
different religions can be a cause of religious conflict.

8. Jens
Martensson
TYPES OF TRUTH CLAIMS
All statements can be regarded as making a truth-claim.
Truth-claims that can be shown to be true are verified and
those shown to be false are falsified.
• Empirical truth claims
• The sentence The Oxford English Dictionary has a
definition of ‘definition’ can be verified by looking
in the dictionary to see whether the OED has the
appropriate entry. Certain claims, such as claims about
the past or future cannot be supported by direct
evidence and so can only be supported indirectly.
• Statistical empirical statements make a claim about
some proportion of a class of objects or events,
such as: 90% of snapping turtles do not survive the first
three months of life.
• Universal empirical statements make a claim about all
objects or events of some kind, such as: All ravens are
black.
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9. Jens
Martensson
TYPES OF TRUTH CLAIMS (CONT.)
Non-empirical truth claims
• Statements that fall under this category
cannot, in principle, be verified on the
basis of empirical evidence. Statements
that fall in this category are moral,
aesthetic, religious and mathematical.
• In ethics, such principles are moral
principles—they enable one to
determine the truth of any moral claim.
• In religion these principles are
principles that must be accepted on
faith.
• In mathematics these principles are
axioms that are, usually, taken to be
self-evident.
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10. Evaluating arguments
Definition: To evaluate means to judge or assess.
Purpose: It is important for a reader to be able to process
information given and decide if the information is factual,
leading or biased in order to form an opinion.
 Evaluate Types of Evidence
 Is it sufficient to support the claim?
 Is the evidence relevant to the claim?
 Can the evidence be proven as fact, not opinion?
 Is there bias?
 Personal experiences may be biased
 Watch for leading language
Words that have strong positive or negative connotations
like “wise” or “terrible”.
 Did the author omit (leave out) important information?

11. Evaluating
arguments
(cont.)
Opposing Viewpoints or Counter-argument
 Does the author address opposing
viewpoints clearly and fairly?
 Does the author refute the opposing
viewpoint with logic and relevant evidence?
Advertising or Propaganda Techniques
 Bandwagon technique: “Everyone is doing
it! You should too!”
 Plain Folk: the “average” person uses this or
a politician can relate to the typical American
 Celebrity or Doctor Endorsement: Adam
Levine for Proactive.

12. Jens
Martensson
Strategies
for evaluating
an argument
• Identify the claim.
• Outline the reasons to support the
claim.
• What types of evidence are used?
• Evaluate the evidence. Is their enough
evidence provided and does it make
sense?
• What emotional appeals are used?
• Is there language with strong positive or
negative connotations?
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13. Jens
Martensson
When an argument is
a good one?
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Arguments can be good or bad in various ways. To help us understand what
a good argument is from the standpoint of critical thinking, we begin by spelling
out a few things that a good argument is not.
What “Good Argument” Does Not Mean:
• “Good Argument” Does Not Mean “Agrees with My Views”
• “Good Argument” Does Not Mean “Persuasive Argument”
• Persuasive Argument: An argument that actually succeeds in convincing an
audience to accept a conclusion.
• • Does this hold true of arguments as well?
• • Is a good argument a persuasive argument?
• • Its not necessarily and for two reasons.
• “Good Argument” Does Not Mean “Well-Written or Well-Spoken
Argument”

14. Jens
Martensson
When
an argumen
t is a good
one?
What “Good Argument” Does Mean:
• A good argument is basically an argument in which two
conditions are met:
 All the premises are true
 The premises provide good reasons to accept the conclusion.
• A set of premises provides good reasons to accept a
conclusion when the argument is either deductively valid
or inductively strong.
• Deductively Valid: An argument is deductively valid if the
conclusion must be true if the premises are true.
• Inductively strong: An argument is inductively strong if the
conclusion is probably true if the premises are true.
• A good argument, from the standpoint of critical thinking, is
an argument that satisfies the relevant critical thinking standards
that apply in a particular context. The most important of these
standards are accuracy (Are all the premises true?)
and logical correctness (Is the reasoning correct? Is the
argument deductively valid or inductively strong?).
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15. Jens
Martensson
Evaluating Arguments:
Some General Guidelines
Given the general definition of “good argument,” we can offer
the following general guidelines on evaluating arguments.
• Are the premises true?
• Is the reasoning correct? Is the argument deductively valid
or inductively strong?
• Does the arguer commit any logical fallacies?
• Does the arguer express his or her points clearly and precisely?
• Are the premises relevant to the conclusion?
• Are the arguer’s claims logically consistent? Do any of
the arguer’s claims contradict other claims made in the argument?
• Is the argument complete? Is all relevant evidence taken
into account (given understandable limitations of time, space,
context, and so on)?
• Is the argument fair? Is the arguer fair in his or her
presentation of the evidence and treatment of opposing arguments
and views?
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16. Jens
Martensson
When is it
reasonable to accept
a premises?
• All good arguments, as we have seen, have true premises. But
when is it reasonable to accept a premise as true?
• Let’s suppose that somebody asserts a claim—for example,
that women are more superstitious than men or that I saw Elvis
at a Dunkin’ Donuts in Lubbock. For simplicity, let’s suppose
that the claim is unsupported (i.e., no argument is given for it)
and that for some reason it is either impossible or not
worthwhile to try to verify the claim for ourselves.
Under what conditions is it reasonable to accept such a claim?
• The most general principle can be summed up in the following
principle of rational acceptance: generally speaking, it
is reasonable to accept a claim
• If the claim does not conflict with personal experiences that we
have no good reason to doubt
• The claim does not conflict with background beliefs that we
have no good reason to doubt
• The claim comes from a credible source.
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17. When is it
reasonable to
accept a
premises?
Does the claim conflict with our personal
experiences?
 Sometimes people claims that conflict with our own
personal observations and experiences. When this
happens it is usually best to trust our own
experiences.
 Critical thinkers also recognize that their beliefs,
hopes, fears, expectations, and biases can affect their
observations. Children, for example, “see” monsters
in the closet. Sports fans perceive referees as partial
to the other team.
 In short, personal experiences are often less reliable
than we think. We need to be aware that often
“believing is seeing” and that things are not always
as they appear.

18. When is it
reasonable to
accept a
premises?
Does the Claim Conflict with Our Background Beliefs?
 Sometimes a claim doesn’t conflict with any of our personal
observations or experiences but does conflict with certain
background beliefs we hold.
 By “background beliefs” we mean that vast network of conscious
and unconscious convictions we use as a framework to assess the
credibility of claims that can’t be verified directly. In general, if a
claim fits well with our background beliefs, it is reasonable for us
to accept it.
 For example, the claim, “It was hot in Las Vegas last fourth of
July,” is quite believable given background information most of
us share about midsummer weather conditions in the Nevada
desert. The claim, “It snowed in Las Vegas last Fourth of July,”
however, would rightly be rejected out of hand unless it was
accompanied by strong supporting evidence.
 The problem is that most of us place too much confidence in the
accuracy of our background beliefs. A chain is only as strong as
its weakest link.

19. When is it
reasonable to
accept a
premises?
Does the Claim Come from a Credible Source?
 Much of what we believe about the world is based
on testimony or authority. All of us believe, For
example, that George Washington was the first
president of the United States, that the earth
revolves around the sun, that there is such a place as
the Sahara Desert, and that it is cold at the North
Pole in January. Yet few of us have personally
verified any of this information for ourselves.
 Thus, a crucial Question for critical thinkers is
When is it reasonable or justifiable to accept a claim
based simply on the testimony or authority of
another?

20. When is it
reasonable to
accept a
premises?
Good reasons to doubt the credibility of a source may include the
following:
 The source is not a genuine expert or authority.
 The source is speaking outside his or her area of expertise.
 The source is biased or has some other motive to lie or mislead.
 The accuracy of the source’s personal observations or
experiences is questionable.
 The source is contained in a source (e.g., a supermarket tabloid
or sensationalistic Web site) that is generally unreliable.
 The source has not been cited correctly or has been quoted out
of context.
 The issue is one that cannot be settled by expert opinion.
 The claim made by the source is highly improbable on its face.

21. Jens
Martensson
Refuting argument
To refute an argument isn’t merely to
challenge, rebut, or criticize it. It is to defeat
it, to show that the premises do not provide
convincing reasons to accept the conclusion.
Arguments can be criticized in various ways
(e.g., as obscure, wordy, or repetitious).
But there are only two ways in which an
argument can be refuted:
• Show that a premise—or a critical group
of premises—is false or dubious.
• Show that the conclusion does not
follow from the premises.
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22. Jens
Martensson
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Strategy 1
Sometimes it is possible to defeat an argument by showing that a single premise is false.
Consider this example:
• All presidents live in the White House.
• Paris Hilton is president.
• So, Paris Hilton lives in the White House.
Some arguments, however, cannot be refuted simply by showing that one
of their premises is false. Here is an example:
Example :
• Children who have unsupervised access to the Internet may be exposed to pornographic and
violent images.
• Some sexual predators use the Internet to find and communicate with children.
• Children have no ability to use a keyboard or mouse correctly.
• So, children should not be allowed unsupervised access to the Internet.

23. Jens
Martensson
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Strategy 2
• The second way to refute an argument is by showing
that the reasoning is faulty—that the conclusion does
not follow properly from the premises.
Here are two examples:
• Get high-speed Internet access by satellite. It’s fast, reliable, and won’t tie up your
phone lines.
• All mothers should stay home with their young kids. It would promote closer
family ties, and studies show that children with stay-at-home moms do better in
school, have higher self-esteem, and are less likely to get involved with drugs or
commit crimes.
In evaluating arguments of this sort, the important question to keep in mind is:
• Do the premises provide enough evidence for the conclusion?

24. THANKYOU!
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