Reasoning and Argument Analysis
Clark Wolf
Director of Bioethics
Iowa State University
jwcwolf@iastate.edu
OBJECTIVES: On completion of this unit,
students should be able…
1.1 …to recognize when they are presented with an argument,
1.2 …to analyze arguments by identifying the conclusion and
distinguishing conclusions from premises.
1.3 …to evaluate arguments by considering the plausibility of the
premises and the extent to which the premises support the
conclusion.
1.4 …to distinguish deductive and inductive arguments,
1.5 …to distinguish an argument’s content from its form.
1.5 …to define key concepts: argument, premise, conclusion, evidence,
rationally persuasive argument, fallacy, valid argument, invalid
argument, inductive argument, abductive argument.
1.6 …to evaluate arguments, by (i) distinguishing premises from
conclusion, (ii) putting the argument in standard form, (iii)
critically examining the premises, and (iv) evaluating the
inference from premises to conclusion.
1.7 …to be self-reflectively critical of their own arguments and those of
others.
What is an Argument?
Argument: A set of statements, some of which serve as premises,
one of which serves as a conclusion, such that the premises
purport to give evidence for the conclusion.
Premise: A premise is a statement that purports to give evidence for
the conclusion.
Evidence: To say that a statement A is evidence for another
statement B is to say that if A were true, this would provide some
reason to believe that B is true.
Conclusion: The statement in an argument that is supposedly
supported by the evidence.
When do we encounter arguments?

Any time anyone tries to persuade you of
something, or to make you change your mind.
Rational persuasion uses reasons, but even
irrational persuasion employs reasons (bad
reasons). In evaluating arguments, we need to
be able to evaluate reasons and patterns of
reasoning.
Indicator Words:

Indicator words: Sometimes writers use language that
indicates the structure of the argument they are giving.
The following words and phrases indicate that what
follows is probably the conclusion of an argument:

Therefore…
thus…
for that reason…
hence…
it follows that…




Conclusion Indicators:
Because…
 Since…
 For…
 For the reason that…

Example:

“Because animals are conscious, capable
of experiencing pain and pleasure, they
are like people in significant respects.
Since they are also intelligent—often far
more intelligent than newborn babies for
example, it follows that they deserve kind
treatment from human beings and that it is
wrong to treat them with cruelty.”
Examples:
Since private business is the most effective
instrument of economic change, the government
should utilize the resources of private business
in its economic planning and decision making.
Women work just as hard as men and are just
as productive. Therefore they should be
compensated the same.
Standard Form

Standard Form: Usually we find arguments
expressed in ordinary prose. But as noted,
when we are evaluating arguments it is a good
idea to separate the premises from the
conclusion, and to put the argument into
“standard form.” We say that an argument is in
standard form when the premises are
numbered and listed separately, and when the
conclusion is clearly written underneath them.
Standard Form Version:
(1) Animals are conscious.
(2) Animals are capable of experiencing pain and
pleasure.
(3) Animals are intelligent.
(4) Animals are like people in significant respects.
Conclusion:
(5) Therefore (i) animals deserve kind treatment from
humans and (ii) it is wrong to treat animals with cruelty.
A Reservation:
Whenever we put an argument in standard
form, we have given an interpretation of
that argument. Ideally, an interpretation
should accurately capture the meaning of
the original, but it is always possible to
challenge the accuracy of an
interpretation.
Evaluating an Argument:
“By splicing genes into crop plants, scientists
have changed these crops in ways that never
could have come about through the natural
process of selective breeding. These changes
in our food crops threaten the health of
everyone in the world, and impose a great
danger of massive environmental damage.
Genetically modified crops are unnatural and
dangerous. We should avoid using them and
growing them, and should do whatever it takes
to eliminate them from Iowa farms.”
Questions:
What is the author of this passage trying
to persuade you to believe? (What’s the
conclusion?)
 What reasons are being offered? (What
are the premises?)
 In this argument there are few indicator
words used, but it is not hard to figure out
what the author would like us to believe.

What’s the Conclusion?

Conclusion: Often the conclusion of an argument is
stated either in the first sentence of a paragraph, or in
the last sentence of the paragraph. In this case, the
conclusion—the claim the author intends to persuade us
to accept—is a complex claim. The author urges that:

(1) We should avoid using and growing genetically
modified crops, and
(2) We should do “whatever it takes” to eliminate these
crops from Iowa farms.

What’s evidence or reasons are given?

Premises:
P1) Gene splicing changes crops in ways that could never
have come about through selective breeding.
P2) Changes in food crops due to gene splicing threaten
everyone’s health.
P3) Changes in food crops pose a threat of massive
environmental damage.
P4) Genetic modification of crops is unnatural.
P5) Genetic modification of crops is dangerous.
Step One: Are the premises true?

Premise 1: Gene splicing changes crops in ways that
never could have come about through selective
breeding.

Evaluation: Is this true? Some of the properties that
have been induced through genetic engineering might
have been produced through selective breeding. But it
is unlikely that the genetic alterations that have been
effected in the production of genetically modified crops
would have been produced in any other way. Perhaps
this premise should be somewhat qualified, but it
contains a kernel of truth.
Step One: Are the premises true?

Premise 2: “Changes in food crops due to gene
splicing threaten everyone’s health.

Evaluation: This claim requires additional
support and evidence. Many people are
concerned about the health effects of genetically
modified food crops, but no one has shown that
these crops are dangerous. The author of the
paragraph provides no evidence that genetically
modified crops are dangerous.
Step One: Are the premises true?

Premise 3: Changes in food crops pose a threat
of massive environmental damage.

Evaluation: Once again, this claim requires
support. There may indeed be reasons for
concern about the environmental effects of
genetically modified crops, but the author has
not given us any evidence. Without more
evidence, we may not be in a position to
evaluate this premise.
Step One: Are the premises true?

Premise 4: Genetic modification of crops is
unnatural.

Evaluation: The term ‘natural’ can be slippery,
and we may need to know more about what the
author has in mind. In context, it seems that the
author regards things that are ‘unnatural’ as
bad. But in an important sense, bridges,
computers, vaccines and artworks are
“unnatural.”
Step One: Are the premises true?

Premise 5: Genetic modification of crops is
dangerous.

Evaluation: Once again we need evidence for
such a claim before we can place our trust in it.
In what sense is genetic modification
dangerous, and what are the specific dangers
the author has in mind? Without more evidence,
we may simply find that we are not yet in a
position to evaluate the argument.

Step Two:
If the premises were true, would they
provide good evidence for the
conclusions?
 Are there implicit premises that should
be included in the evaluation of the
argument?


A Strategy for Evaluating Arguments: Of course, for the
purposes of this course, your views about GM crops are not
what matter. What does matter is the strategy used here for
evaluating the argument under consideration:

First, identify the argument’s premises, and restate them
clearly.

Second, evaluate each premise individually: is it true or false?
What evidence, what information would you need to know in
order to determine whether the premises are true?

If you discover that the premises of the argument are simply
false, you may need to go no further. But if the premises seem
true, there is a third important step to take in evaluating the
argument:

Third, consider the relationship between the premises and the
conclusion. What kind of argument is it? Is it a good argument
of its kind?
Fallacies:

Fallacy: An argument that provides the
illusion of support, but no real support, for
its conclusion.
Evaluating Philosophical Arguments:

Fair-Mindedness and the State of
Suspended Judgment: When evaluating
arguments, we should strive to be
impartial and fair-minded. We should try
to follow where the best reasons lead
instead of pre-judging the conclusion.

Argument for Analysis:
There is no universal standard for right and
wrong. Different people simply have different
views and different values. None of us is in a
position to say that our values or our moral
judgments are privileged, or that they are
uniquely better than the judgments of others.
What do we learn from the
Bloggs Cases?
Ethical Theory:



We reveal our ethical views when we explain or justify
our choices and behavior to others.
Ethical views can be thoughtless and unreflective, or
thoughtful and reflective. To the extent that we’re
thoughtless and unreflective, our value system will lack
integrity and depth.
If our values are shallow and incoherent, we will make
bad decisions, …and we will be shallow and
incoherent. (?)
Stop here…
ON TO PLATO!
Reasoning in Ethics:

Rachels notes that “philosophy is not like
physics. In physics, there is a large body
of established truth, which no competent
physicist would dispute and which
beginners must patiently master. (Physics
instructors rarely invite undergraduates to
make up their own minds about the laws
of thermodynamics.)” (ix-x)
Reasoning in Ethics

1.1 The Problem of Definition: A theory of
morality is a theory about how we should live
and why. It turns out to be impossible to give a
simple definition of ‘morality.’ This should make
us cautious, but shouldn’t dissuade us from
investigating the subject further. In this book we
will examine alternative theories of morality,
consider the reasons that support or oppose
each of them, and come to evaluative
judgments.
Reasoning in Ethics:

What is the “Minimal Conception of
Morality” that Rachels offers? Is it as
‘minimal’ as he thinks?

Do we need a common minimum before
we can reason about moral questions?

Bloggs Cases
Moral Theory
Metaethics: What is morality? Where
does moral value come from?
Normative ethics: What principles identify
right and wrong conduct?
Applied/practical ethics: What are the
salient ethical considerations in evaluating
specific practices, actions, or
technologies?
Bloggs Case #1
Bloggs Case #1
“Utilitarianism”: The ethical thing to do is
that which maximizes aggregate benefit
for everyone.
“The common good”
Bloggs Case #2
Rights:

Would slicing and dicing Bloggs violate his rights? (What are
rights?)

A person has a right just in case our obligations toward her are
based on the effect that our treatment will have on her, not on
others.

Animals have rights just in case our obligation to treat them
humanely are based on the effect that this treatment would have
on the animals themselves, not the effect it would have on other
people.
Bloggs Case #2
Response: Slicing and dicing Bloggs would violate his rights.
A moral right is a justified claim that an individual (or group) may make
to certain objects or certain treatment by others.
Bloggs’s right to X may take the form of:
A claim that Bloggs may make to a particular object (e.g., his kidneys)
A constraint on how Bloggs should be treated (e.g., he shouldn’t be killed
for his organs)
An obligation on others not to interfere with Bloggs’s doing X (e.g., his
continuing to live)
Ethical Theory


Kant: Categorical Imperative:

“Act only such that you could will the maxim on which you
act as a universal law.”

“Act so that you treat humanity, whether in your own
person or that of another, always as an end in itself, and
never as a means only.”
Would ‘slicing and dicing’ Bloggs for his organs
involve treating him as a mere means?
Ethical Theory:

Killing v. Letting Die: It has sometimes
been argued that we have a moral duty
not to kill, but no moral duty (or a lighter
moral duty) not to let people die.

Does this distinction explain why we
shouldn’t kill Bloggs for his organs?
Bloggs Case #3
Bloggs Case #3
The ethics of acts vs. omissions
The greater good vs. “clean hands”
Ethical Theory:



We reveal our ethical views when we explain or justify
our choices and behavior to others.
Ethical views can be thoughtless and unreflective, or
thoughtful and reflective. To the extent that we’re
thoughtless and unreflective, our value system will lack
integrity and depth.
If our values are shallow and incoherent, we will make
bad decisions, …and we will be shallow and
incoherent. (?)

Fini.
Rachels’ Examples:
Baby Theresa
 Jodie and Mary
 Tracy Lattimer Case
 Case of Fauziua Kassindja

What should we glean
from these cases?
1)
2)
3)
Some Basic Moral Considerations: Benefit to
others, Do no harm, Sanctity of life, truth
telling, etc.
Is there a basic common moral minimum?
Moral judgments have reasons: they are
supported by our beliefs, and by lines of
reasoning. Therefore we can critically
evaluate our moral judgments using the tools
of argument analysis.

Moral Reasoning: Whether we agree about the
verdicts in these cases or not, we can agree that
our moral judgments are based on reasons, that
we can articulate these reasons and evaluate
them, that we can examine how competing
reasons interact with one another. Morality is
therefore about reasoning, not just about
reasonless or intuitive judging.

Requirement of Impartiality: This, according
to Rachels, is the idea that every person’s
interests are equally important from the moral
point of view. Impartiality of this sort is a
commitment.
Next: Deductive Arguments
and Moral Relativism

Deductive Argument: An argument that
has the property that if the premises are
true, then the conclusion cannot be false.

Example:



All vertibrates have hip bones.
Snakes are vertibrates.
Therefore, snakes have hipbones.
Cultural Relativism
“There is no universal standard for right
and wrong. Different people simply have
different views and different values. None
of us is in a position to say that our values
or our moral judgments are privileged, or
that they are uniquely better than the
judgments of others.”
We will not cease from exploration
And the end of our exploring
Will be to arrive where we started
And know the place for the first time.
--T.S. Eliot, Four Quartets

An Argument for Analysis:
All loyal Americans should proudly vote for George Bush
in the upcoming election. In times of crisis, we should
avoid loosing face before the world community by voting
a proven leader out of office. George Bush has shown
that he can make decisive and forceful decisions, and
his efforts in Afghanistan and Iraq have earned him the
respect of the American people, and of our allies
overseas. It is unthinkable that we might vote such a
leader out of office.

Argument for Analysis:

Only by replacing Bush can we hope for a peaceful exit
for our troops in Iraq and Afghanistan. Because the
Iraqui and Afghan people regard US troops as
conquering invaders, they hate our soldiers and take
every opportunity to harm and abuse them. Because of
this, US troops are uniquely ill-suited to bring order and
stability to these war torn nations. Only an international
force could gain the trust of the people of Iraq and
Afghanistan, and only a force that gains their trust can
maintain stability and peace. But George Bush has
squandered the good will of the international community,
and it is unlikely that any international force will help us
while he is in office.