Notes related to chapter 11 of Chaffee’s Thinking Critically and Flew, How to Think Straight, chapters 4, 6 and
7
Defining Inductive
Reasoning: How does it differ from
deduction?
Inductive reasoning: the content of the conclusion goes beyond
the content of the information provided in the premises. Sometimes inductive reasoning “goes” from
the particular to the general, but it does not always do so. The same can be said about deductive
reasoning: sometimes it goes from the general to the specific, but other times
it doesn’t.
Generalizations and Causal Arguments
Generalizations
Empirical generalizations
– use of a sample population to reach a conclusion about a target population.
·
Clearly defined
sample
·
Sufficient size
·
Representative
o Biased samples
Causal Arguments
Necessary and sufficient conditions: knowing the definitions
Necessary
condition – contributing “cause” – without this particular “thing,” the effect
can’t happen. So, oxygen is a necessary
condition for fire. But it is not a
sufficient condition, or we would all be on fire right now. It is a necessary condition for getting an A
in this course that you get at least 100 out of 150 points on the first exam,
but it is certainly not the case that simply doing that will get you an A in
the course.
Sufficient
condition – sufficient cause – this is a cause that will by itself produce an
effect, but it is possible that something that is a necessary condition for the
occurrence of an event or effect might be replaced by something else that will
also do the trick. So, for example,
being run over by a steamroller is a sufficient condition for death, but so
also is being crushed (completely) by a bus.
A sufficient condition for getting an A in this course is that you have
a 95% average on all coursework.
A
necessary and sufficient condition is one that is both the cause and the ONLY
cause for the production of an event.
In the absence of this causal factor, the event cannot occur, and when
the thing is present, the effect will definitely occur. Very few causes are both necessary and
sufficient for the production of an event.
Examples and exercises on page 508 – 509.
Fallacious Reasoning –
Unsound (non-cogent) arguments that may be persuasive but are erroneous because
they appeal to emotion, prejudice, wishful thinking, or in some other way are
not consistent with the criteria of cogent reasoning.
See Flew, p. 111, section 6.42 on
caution regarding identification of fallacious reasoning: “When we first become acquainted with some
fallacy, as students of the present book need to recognize, it can be almost
irresistibly tempting to identify arguments as tokens of this fallacy type when
what we really have is either a token of some other type or even no fallacy at
all” (Flew, 111). See also Flew,
sections 1.49-1.54.
Fallacy
categorization is indicated by HC (Hasty Conclusion) and IR (Irrelevant Reason)
Premise Problems are
indicated by PP.
References to
Flew’s text:
·
P. 62 -- The
distinction between providing a proof of a claim and persuading a person to
believe a claim. (Fallacious arguments
are often very persuasive, but that doesn’t make them good arguments except in
the sense that the person putting forth the argument has succeeded in winning
others over to the cause or belief.)
·
There are
different senses of the term “reason” – one is that there are good grounds for
holding that a proposition is true.
Another is reason as a motive for persuading oneself that a claim is
true. Another is the sense of a cause
for something happening or being the case.
See sections 4.4-4.8.
o
Note Flew’s
use of Pascal’s Wager on p. 63 as distinguishing between the first two sense of
“reason” – as grounds and as motive for believing that God exists.
Fallacies of False Generalization
·
Hasty generalization (HC) Hasty Generalization
(sometimes called "Converse Accident") -- note the relationship to
"Accident". This fallacy
occurs when one attempts to form a general rule from particular cases when
there is not enough evidence to do so.
For example, one may argue that since narcotics are beneficial to people
in great pain, they ought to be made available to the general public.
o Composition: Arguing
from the parts of the whole to the attributes of the whole itself. For example, one may argue that since every
part of a particular machine is light, the entire machine is light.
o
The reverse of composition is
DIVISION: Accident (Division): Applying a general rule to a particular case
when the general rule does not apply.
E.g., "You should always pay your debts." This would not be the case in a particular
case even if it is true generally.
There are times when paying one's debts might be excepted with
qualification. Arguing from the whole down to the attributes of the parts. Simply because an entire machine is heavy,
it does not imply that all the parts are heavy. See
Flew, p. 105 for further explanation.
o
·
Sweeping Generalization (HC)
·
“Black or White Fallacy” (HC or IR), False Alternative (False Dilemma): When this fallacy is
used in argumentation, it is usually employed such that the person to whom the
argument is directed is given two choices in a particular matter when in fact
there are more possibilities. For
example, one may claim that "you are either for us or against us." In fact, one may be neutral.
1.
See Flew, p. 124, section 7.24: Example of the distinction between
selfishness and self-interest.
·
See Flew, p. 122, section 7.17-7.23 on
the “BLACK IS WHITE” FALLACY. This is a
problem in reasoning in which one assumes that since there is no steadfast rule
for determining a sharp division between two or more things, there really is no
division or dividing line between them at all.
·
Faulty Analogy. Analogies proceed on the basis of a
comparison of two things, principles, or concepts which have characteristics in
common. From those similarities, one
concludes that, for example, since object A has property X, object B has
property X simply because they had other properties in common. There are cases in which analogies are not
faulty, but this depends both on the type of information presented, and how
much of it is given. For example, one
may argue that since dogs and cats are both domestic animals, both are
quadrupeds, and both are mammals, that since dogs bark, cats do, too. Obviously fallacious.
Causal Reasoning: Fallacies (begins p. 538)
·
Questionable Cause – e.g., superstitions (HC)
·
Misidentification of a Cause (note that this is also related to errors in the
construction of argument diagrams) – see p. 539 – (HC)
·
Post Hoc Ergo Propter Hoc (HC) Post Hoc: Causal
Fallacy. The basic structure of this
argument is "A occured before B, therefore A caused B". The problem here is one of hasty conclusion. The simple fact that one even precedes
another is not necessarily sufficient evidence to believe that the first event
caused the second. See Flew, p. 109, section 6.38 and section 1.53
for “Whatever-follows-must-be-the-consequence” fallacy (Post Hoc).
·
Slippery Slope (HC). See Flew, p., 74, for the “domino effect” or “slippery
slope” with reference to argumentation of this sort and that it is often the
case that those who believe in the “domino effect” rarely have reasons to hold with the view. It is entirely possible that you are guilty of committing this
fallacy in cases like those described by Flew such that: “Once we have
recognized that it is possible, even likely, that policies may have
consequences which were not intended by the promoters of those policies, we
ought at least to hesitate and seek clearer evidence before accusing them of
conspiring to produce those consequences” (Flew, 74).
·
See Flew, p. 96 – care should be taken
in the evaluation and use of statistical information. “Obviously the possibilities of error will increase with any
increase in the quantity and complexity of the statistics available; obviously,
too, to broach the question of the reliability of the figures offered is to
open up a new dimension of difficulty and maybe duplicity. But people do often
exaggerate the importance of the intention to hoodwink others as a cause of the
isinterpretation of figures which, if properly understood and correctly
interpreted, are quite sufficiently accurate.
For most of us …are fully capable
of drawing incorrect conclusions without either ourselves or anyone else intending
that we should do so” (Flew, 96, emphasis added). See also Flew, pp. 128-129, sections 7.35-7.37 on the use and
careful use of statistical information and its interpretation.
Fallacies of Relevance (Forms of Irrelevant
Reason/Irrelevant Conclusion/Non-Sequitur) Non Sequitur (Irrelevant Reason, Irrelevant
Conclusion): Takes several forms, many of which have no specific names. Non Sequitur is usually used for the generic
approach to fallacy identification.
Some forms are Straw Man Argumentation and Diversion. Generally speaking, a straw-man argument is
one in which the arguer attempts to provide support for his own position by
discrediting the opposite position by describing it in unfair terms. The fallacy of diversion is usually used
when one does not have sufficient support for his own claim, and therefore
supports some other, but related claim.
Other forms of this fallacy are "evading the issue" (which is
fairly well self-explanatory).
·
Appeal to Authority (Argumentum ad Vericundiam) – note cases in which it is not fallacious. (IR) Appeal to Authority
(Argumentum ad Vericundiam): Not always fallacious. This form of argumentation is fallacious when an appeal to an inappropriate
authority figure is used to gain acceptance of a claim. This fallacy appears regularly in
advertising.
·
Appeal to Tradition (IR)
o The Bandwagon – everybody’s doing it, everybody believes
it
1.
Argumentum ad Populum (appeal to popularity): Appeal to the Majority (Argumentum ad Populum): The
appeal to a large percentage of a population or group is used as evidence for
the belief that a position is true.
·
Appeal to Pity (Argumentum ad Misericordiam) (IR): Appeal to Emotion: An appeal to the emotions of a
person or group to whom an argument is directed. Usually takes the form of guilt, rage, pity (Argumentum ad
Misericordiam), etc., in attempting to win the acceptance of a claim.
·
Appeal to Fear (IR)
o Note relationship to Appeal to Force/Argumentum ad Baculum: Appeal to Force
(Argumentum ad Baculum): May be considered an appeal to emotion. The misleading part of this fallacy is that
if someone is threatening to use force against someone else, it is a good
reason (in some cases) for saying that the claim is true; but it is
still not a good reason to believe that the same claim is true.
·
Appeal to Flattery (IR)
·
Special Pleading (special exceptions) (IR)
·
Appeal to Ignorance (Argumentum ad Ignorantiam) (IR) The simplest form of
this argument is to claim that because there is no evidence against a position,
it must be true; or, conversely, to claim that since there is no evidence for a
position, it must be false.
·
Begging the Question/Circular Argument/Petitio
Principii (PP) Begging the Question (Circular Argumentation, Petitio Principii):
Simply put, circular argumentation amounts to supporting a position by using
that position as support for itself.
This fallacy rarely appears in its most blatant form, one in which the
premise and conclusion say exactly the same thing in exactly the same way. But there are some ways in which this
fallacy can be accepted as good argumentation, especially when the arguer conceals
the conclusion's inclusion in the premise by making the premise and conclusion appear
to say different things. See Flew, p. 73 for
taking care in not committing this error in reasoning yourself.
·
Straw Man (PP and IR)
·
Red Herring (smoke screen) – introducing irrelevant topics/evading the
issue (IR)
·
Ad Hominem (IR) Argumentum
ad Hominem:
Takes at least two forms - negative and
positive. Depends on discrediting
(or justifying through laudatory comments) the claim of some other person based
on personal characteristics. This can
also be used against groups, nations, etc.
It can also take the form of the "you, too" (tu quoque) form
of argument in which one justifies his own position by pointing out that
someone else "is doing it, too."
It can also take the form of discrediting a position by giving it in a
negative light ("poisoning the well").
o The
Genetic Fallacy See also Flew, p. 66 on the care that should be taken in accusing someone
of committing this fallacy. Simply
because someone is paid to make a claim, or otherwise has reasons of his or her
own for believing (or having others believe) that a certain claim is true or a
course of action ought to be taken does not imply that the claim or course of
action must be false simply because that person has reasons other than good reasons to hold with it. See sections 7.10-7.17.
o Poisoning
the Well
·
Two Wrongs (Tu Quoque) (IR) or Excusing
Practice
·
Added Fallacies and
Premise Problems:
o Falsehood/
“Unknown (or unknowable) Fact” (PP)
o The Fallacy of Association (IR). See Flew, p. 127,
section 7.32 on advertising.
Associations with people, places and activities found attractive. Note also that association may take a very
negative version as well – as in “guilt by association.”
o
Distortion (ambiguity) (PP)
o
Omitted or Suppressed Evidence (HC)
o Subjectivism (IR): The
fact that one has a belief or desire is used as evidence for the truth of the
claim.
o
Equivocation (This should be
subsumed under the heading of "premise problems"). This fallacy occurs when words have more
than one meaning, and that meaning is either intentionally or unintentionally
confused in the process of argumentation.
A simple example of this fallacy is to claim that since good steaks are
rare these days, you shouldn't order yours well done. See
Flew, sections 1.14-1.15, 1.30, 4.4-4.10.
Note that equivocation is a form of ambiguity – this is distinct from
vagueness. Terms can be vague – but when
a person uses a vague term, he or she generally has not defined the term in
question, and so it can be used in a variety of ways. Ambiguity comes about as a result of using a word intentionally or accidentally in two or
more different ways.
o
Complex
Question (Leading Question): See
Flew, p. 116 – sometimes also called “The Fallacy of Many Questions”
o
See Flew, pp. 130-132, sections
7.39-7.43 on The
Naturalistic Fallacy (what is, is what ought to be and what is natural is what
ought to be preferred, chosen, etc.).
See pp. 552-559 (A Guide
to Reasoning – how to construct good arguments)
Sample Fallacies
You
shouldn't pay attention to Smith’s opinion.
He failed logic twice.
I don't
think we should give full weight to the opinions of Smith and Jones. They work together and grew up together.
If you hold
that in a time of emergency, every citizen should contribute to his country's cause,
you at the same time advocate drafting children.
You can’t
hire him to work with us. He’s a drunk.
There should
be no grades given at universities to determine success in a course. A person is either good enough or not good
enough, a person is either smart or stupid.
Why should
there be academic probation? Where’s
the big difference between a GPA of 1.75 and 1.74?
I don’t see
why we should listen to Dr. Smith on the issue of reproductive technology. We need to consult an authority. And Smith clearly isn’t one because he
doesn’t have enough authority to keep his children in line. Did you read in the paper that his son was
arrested?
Mr. Smith
went outside and watched fireworks go up in his underwear.
Did you hear
that Luigi’s Pizza is delivered free.
We should get one.
Bob is a
very poor teacher.
If you ever
drove a Buick, you would know how good GM cars really are.
The bank
won’t give you a loan because you have no credit record. There is therefore no evidence that you have
or do make installment payments on time – or at all.
Women ought
to take their husband’s names when they get married. Marriage is an equal
partnership, and a woman who refuses to take her husband’s name will embarrass
him and, in fact, he ought to re-think marrying someone who refuses to take his
name because it shows that she does not respect him.
Nobody who
drives on Interstate 4 obeys the speed limit.
Everybody goes at least 75 all the time. Why don’t they just raise the speed limit to 75 and get it over
with?
I’ve noticed
that barking for a long time makes my dog hungry. Every time I feed him after he’s been barking for an hour or
more, he eats everything and looks for more.
Philosophy
classes are not regularly taught in high schools, and if there was a good reason
for them to be there, they would have been being taught in high schools all
along.
We won the
election because we had more votes than the opposition.
Mr. X was
removed from office for dishonesty. There
is therefore no reason to read the books he has written. Everything in them is obviously false.
No one can
prove that God exists; so God does not exist.
We would all
be better off if we all had more money to spend. That means that consumers and retailers should have more
money. The way to achieve the goal is
to raise all salaries by 50% and all prices by 50%.
Please don’t
give me a ticket for driving the wrong way on a one way street. If you do, my husband will beat me.
Winter
Haven, Florida has a very high crime rate and it also has a lot of
churches. To curb the crime rate in
that city, we ought to close the churches.
You really
must realize the importance of voting with me on this issue. You wouldn’t want your wife to find out
about what you were doing last weekend at the hotel with your secretary, would
you?
Of course we
shouldn’t listen to the Republicans on this issue. It stands to reason that since they are usually rich people, they
are opposed to social programs.
Can you
believe that the man from Germany said that Americans are warmongers? The stupid fool. He seems to have forgotten that Germany started World War II.
You are
either for us or you are against us in the war against terror.
Every
sentence in the text for this course is well written. Therefore, the entire book is well written.
Give me an
answer right now or I’ll leave and never speak to you again.
Getting a B
in this class is better than nothing.
And nothing is better than understanding logic. Therefore, getting a B in this class is
better than understanding logic.
Abortion is
morally wrong because it has not been established that a fetus is not a human
being.
I deserve to get at least a “C” in this class. If I fail, I’ll be put on academic probation,
I’ll lose my scholarship, and my entire future will be dismal and depressing.