Constructing Arguments - CriticalThinkingWiseman

Constructing Arguments
Critical Thinking
Ch. 10
A form of thinking in which certain statements
(reasons) are offered to support another
statement (conclusion)
Chapter 10
Recognizing arguments
Constructing arguments
Evaluating arguments
Understanding arguments
Constructing extended arguments
Type of thinking that uses argument (reasons
in support of conclusions)
Attempt to explain, justify, and predict things
Cue Words for Arguments
To identify reasons and conclusions
Key words
Signal a reason in support of a conclusion or
conclusion based on certain reasons
In the first place
In the second place
It follows that….
Cue Words signaling reasons
As shown by
As indicated by
Given that
Assuming that
In view of
First, second..
In the first (second)
May be inferred from
May be deduced
For the reason that
Cue Words Signaling Conclusions
It follow that
Thereby showing
Demonstrates that
Allows us to infer that
Leads me to believe that
Allows us to deduce that
(which) shows that
(which) proves that
Implies that
Points to
As a result
Drugs: Case for Legalizing Marijuana
In the Long Run It Would Save Lives And End Hypocrisy
It is possible to stop most drug addiction in the United States within a very short
time. Simply make all drugs available and sell them at cost. Label each drug with a
precise description of what effect--good and bad--the drug will have on whoever
takes it. This will require heroic honesty. Don't say that marijuana is addictive or
dangerous when it is neither, as millions of people know--unlike "speed," which kills
most unpleasantly, or heroin, which is addictive and difficult to kick.
For the record, I have tried--once--almost every drug and liked none, disproving the
popular Fu Manchu theory that a single whiff of opium will enslave the mind.
Nevertheless many drugs are bad for certain people to take and they should be told
about them in a sensible way.
Along with exhortation and warning, it might be good for our citizens to recall (or
learn for the first time) that the United States was the creation of men who believed
that each man has the right to do what he wants with his own life as long as he
does not interfere with his neighbor's pursuit of happiness (that his neighbor's idea
of happiness is persecuting others does confuse matters a bit).
This is a startling notion to the current generation of Americans who reflect on our system of public
education which has made the Bill of Rights, literally, unacceptable to a majority of high school
graduates (see the annual Purdue reports) who now form the "silent majority"--a phrase which
that underestimated wit Richard Nixon took from Homer who used it to describe the dead.
Now one can hear the warning rumble begin: if everyone is allowed to take drugs everyone will and
the GNP will decrease, the Commies will stop us from making everyone free, and we shall end
up a race of Zombies, passively murmuring "groovie" to one another. Alarming thought. Yet it
seems most unlikely that any reasonably sane person will become a drug addict if he knows in
advance what addiction is going to be like.
Is everyone reasonably sane? No. Some people will always become drug addicts just as some
people will always become alcoholics, and it is just too bad. Every man, however, has the
power (and should have the right) to kill himself if he chooses. But since most men don't, they
won't be mainliners either. Nevertheless, forbidding people things they like or think they might
enjoy only makes them want those things all the more. This psychological insight is, for some
mysterious reason, perennially denied our governors.
It is a lucky thing for the American moralist that our country has always existed in a kind of timevacuum: we have no public memory of anything that happened before last Tuesday. No one in
Washington today recalls what happened during the years alcohol was forbidden to the people
by a Congress that thought it had a divine mission to stamp out Demon Rum and so launched
the greatest crime wave in the country's history, caused thousands of deaths from bad alcohol,
and created a general (and persisting) contempt for the laws of the United States.
The same thing is happening today. But the government has learned nothing from past
attempts at prohibition, not to mention repression.
Last year when the supply of Mexican marijuana was slightly curtailed by the Feds, the
pushers got the kids hooked on heroin and deaths increased dramatically, particularly
in New York. Whose fault? Evil men like the Mafiosi? Permissive Dr. Spock? Wild-eyed
Dr. Leary? No.
The Government of the United States was responsible for those deaths. The
bureaucratic machine has a vested interest in playing cops and robbers. Both the
Bureau of Narcotics and the Mafia want strong laws against the sale and use of drugs
because if drugs are sold at cost there would be no money in it for anyone.
If there was no money in it for the Mafia, there would be no friendly playground
pushers, and addicts would not commit crimes to pay for the next fix. Finally, if there
was no money in it, the Bureau of Narcotics would wither away, something they're not
about to do without a struggle.
Will anything sensible be done? Of course not. The American people are as devoted to
the idea of sin and its punishment as they are to making money--and fighting drugs is
nearly as big a business as pushing them. Since the combination of sin and money is
irresistible (particularly to the professional politician), the situation will only grow worse.
Gore Vidal, playwright and novelist, is the author of the newly published "Two Sisters."
The Case for Slavery by A.M. Rosenthal
September 26, 1989ON MY MIND; The Case For Slavery
By A. M. RosenthalLEAD:
Across the country, a scattered but influential collection of intellectuals is intensely engaged in
making the case for slavery.
Across the country, a scattered but influential collection of intellectuals is intensely engaged in
making the case for slavery.
With considerable passion, these Americans are repeatedly expounding the benefits of not only
tolerating slavery but legalizing it:
It would make life less dangerous for the free. It would save a great deal of money. And since the
economies could be used to improve the lot of the slaves, in the end they would be better off.
The new anti-abolitionists, like their predecessors in the 19th century, concede that those now in
bondage do not themselves see the benefits of legalizing their status.
But in time they will, we are assured, because the beautiful part of legalization is that slavery
would be designed so as to keep slaves pacified with the very thing that enslaves them!
The form of slavery under discussion is drug addiction. It does not have every characteristic of
more traditional forms of bondage. But they have enough in common to make the
comparison morally valid - and the campaign for drug legalization morally disgusting.
The Case for Slavery (cont’d)
Like the plantation slavery that was a foundation of American society for so long, drug
addiction largely involves specifiable groups of people. Most of the enchained are children
and adolescents of all colors and black and Hispanic adults.
Like plantation slavery, drug addiction is passed on from generation to generation. And this
may be the most important similarity: like plantation slavery, addiction can de-stroy among
its victims the social resources most valuable to free people for their own betterment family life, family traditions, family values.
In plantation-time America, mothers were taken from their children. In drug-time America,
mothers abandon their children. Do the children suffer less, or the mothers?
Anti-abolitionists argue that legalization would make drugs so cheap and available that the
profit for crime would be removed. Well-supplied addicts would be peaceful addicts. We
would not waste billions for jails and could spend some of the savings helping the addicted
become drug-free.
That would happen at the very time that new millions of Americans were being enticed into
addiction by legalization - somehow. dangerous social disorder.
The Case for Slavery (cont’d)
Are we really foolish enough to believe that tens of thousands of drug gang members would
meekly steal away, foiled by the marvels of the free market?
Not likely. The pushers would cut prices, making more money than ever from the ever-growing
mass market. They would immediately increase the potency and variety beyond anything
available at any Government-approved narcotics counters.
Crime would increase. Crack produces paranoid violence. More permissiveness equals more
use equals more violence.
And what will legalization do to the brains of Americans drawn into drug slavery by easy
Earlier this year, an expert drug pediatrician told me that after only a few months babies born
with crack addiction seemed to recover. Now we learn that stultifying behavioral effects
last at least through early childhood. Will they last forever?
How long will crack affect neurological patterns in the brains of adult crack users? Dr. Gabriel
G. Nahas of Columbia University argues in his new book, ''Cocaine: The Great White
Plague,'' that the damage may be irreversible. Would it not be an act of simple intelligence
to drop the legalization campaign until we find out?
The Case for Slavery (cont’d)
Then why do a number of writers and academicians, left to right, support it? I have
discussed this with anti-drug leaders like Jesse Jackson, Dr. Mitchell Rosenthal of
Phoenix House and William J. Bennett, who search for answers themselves.
Perhaps the answer is that the legalizers are not dealing with reality in America. I
think the reason has to do with class.
Crack is beginning to move into the white middle and upper classes. That is a tragedy
for those addicted.
However, it has not yet destroyed the communities around which their lives revolve, not taken
over every street and doorway. It has not passed generation to generation among them, killing
the continuity of family.
But in ghetto communities poverty and drugs come together in a catalytic reaction that is
reducing them to social rubble.
The anti-abolitionists, virtually all white and well-to-do, do not see or do not care. Either way
they show symptoms of the callousness of class. That can be a particularly dangerous social
Arguments as Inferences
Inferring: a thinking process
Reasoning from what you already know (or
believe to be true) to form new knowledge or
Work from reasons we know or believe it to
form conclusions based on these reasons
Argument to Decide
Reason: Throughout my life, I’ve always been
interested in all different kinds of electricity.
Reason: There are many attractive job
opportunities in the field of electrical
Conclusion: I will work toward becoming an
electrical engineer.
Argument to Explain
Reason: I was delayed in leaving my house
because my dog needed an emergency
Reason: There was an unexpected traffic jam
caused by motorists slowing down to view an
overturned chicken truck.
Conclusion: Therefore, I was late for our
Argument to Predict
Reason: Some people will always drive faster
than the speed limit allows, whether the limit is
55 or 65 mph.
Reason: Car accidents are more likely to
occur at higher speeds.
Conclusion: It follows that the newly reinstated
65-mph speed limit will result in more
Arguments to Persuade
Reason: Chewing tobacco can lead to cancer
of the mouth and throat.
Reason: Boys sometimes are led to begin
chewing tobacco by ads for the product that
feature sports heroes they admire.
Conclusion: Therefore, ads for chewing
tobacco should be banned.
Evaluating Arguments
Investigate 2 aspects of arguments
How true are the reasons being offered to support
the conclusion?
To what extent do the reasons support the
conclusion or to what extent does the conclusion
follow from the reasons offered?
How true are the supporting
Analyze the reasons to determine how true
they are:
Does each reason make sense?
What evidence is being offered as part of each
Do you know each reason to be true based on your
Is each reasons based on a source that can be
Do the reasons support the
Investigate the relationship between the
reasons and the conclusion.
Is the argument valid or invalid? Do the
reasons support the conclusion? Does the
conclusion follow from the reasons being
Soundness of Arguments
True reasons + valid structure = sound argument
False reasons and/or invalid structure = unsound
Truth and validity are not the same concepts
Evaluating arguments effectively involves both the truth
of the reasons and the validity of the argument’s
Deductive Arguments
Associated with study of logic
If you accept the supporting reasons
(premises) as true, then you must necessarily
accept the conclusions as true.
An argument form in which one reasons from
premises that are known or assumed to be true
to a conclusion that follows necessarily from
those premises.
Argument form that consists of 2 supporting premises
and a conclusion
Reason/Premise: All men are mortal.
Reason/Premise: Socrates is a man.
Conclusion: Therefore, Socrates is mortal.
Not all syllogisms are valid. Invalid deductive forms:
All men are mortal.
Socrates is a man.
Therefore, all men are Socrates.
Socrates Syllogism: Application of
a General Rule: All A is B.
Premise: All A (men) are B (mortal)
Premise: S is an A (Socrates is a man)
Conclusion: Therefore, S is B (Socrates is a
Effective discussion
Listening carefully to other points of view
Supporting views with reasons and evidence
Responding to the points being made
Asking – and trying to answer – appropriate
Working to increase understanding, not simply
to “win the argument”
Constructing Extended Arguments
Define a thesis
Conduct research
Organize ideas.
Modus Ponens
Affirming the antecedent
 Premise: If I have prepared thoroughly for the final
exam, then I will do well.
 Premise: I prepared thoroughly for the exam.
 Conclusion: Therefore, I will do well on the exam.
Argument Structure
 If A, then B.
 Premise: A
 Conclusion: Therefore B.
Modus Tollens
Denying the consequences
 Premise: If Michael were a really good friend, he would
lend me his car for the weekend.
 Premise: Michael refuses to lend me his car for the
 Conclusion: Therefore, Michael is not a really good friend.
Argument structure
 Premise: If A, then B.
 Premise: Not B.
 Conclusion: Therefore, not A.
Disjunctive syllogism
Presenting several alternatives
 Premise: Either I left my wallet on my dresser, or I
have lost it.
 Premise: The wallet is not on my dresser.
 Conclusion, Therefore, I must have lost it.
Argument structure
 Premise: Either A or B.
 Premise: Not A.
 Conclusion: Therefore, B.