ACC What Is a Logical Fallacy as The Logician Understands It Philosophy Questions

The Case for Torture1by Michael Levin, 1983
Professor of Philosophy at City University of New York (CUNY)
It is generally assumed that torture is impermissible, a throwback to a more
brutal age. Enlightened societies reject it outright, and regimes suspected of
using it risk the wrath of the United States.
I believe this attitude is unwise. There are situations in which torture is
not merely permissible but morally mandatory. Moreover, these situations are
moving from the realm of imagination to fact.
Death: Suppose a terrorist has hidden an atomic bomb on Manhattan
Island which will denotate on noon July 4 unless… (here follow the usual
demands for money and release of his friends from jail). Suppose, further, that
he is caught at 10am of the fateful day, but – preferring death to failure – won’t
disclose where the bomb is. What do we do? If we follow due process – wait for
his lawyer, arraign him – millions of people will die. If the only way to save those
lives is to subject the terrorist to the most excruciating possible pain, what
grounds can there be for not doing so? I suggest there are none. In any case, I
ask you to face the question with an open mind.
Torturing the terrorist is unconstitutional? Probably. But millions of lives
surely outweigh constitutionality. Torture is barbaric? Mass murder is far more
barbaric. Indeed, letting millions of innocents die in deference to one who
flaunts his guilt is moral cowardice, an unwillingness to dirty one’s hands. If you
caught the terrorist, could you sleep nights knowing that millions died because
you couldn’t bring yourself to apply the electrodes?
Once you concede that torture is justified in extreme cases, you have
admitted that the decision to use torture is a matter of balancing innocent lives
against the means needed to save them. You must now face more realistic
cases involving more modest numbers. Someone plants a bomb on a jumbo jet.
1
Originally published in Newsweek, 7 June 1983, p. 13
Levin 1983: “The Case for Torture”
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He alone can disarm it, and his demands cannot be met (or if they can, we
refuse to set a precedent by yielding to his threats). Surely we can, we must, do
anything to the extortionist to save the passengers. How can we tell 300, or
100, or 10 people who never asked to be put in danger, “I’m sorry, you’ll have
to die in agony, we just couldn’t bring ourselves to…”
Here are the results of an informal poll about a third, hypothetical, case.
Suppose a terrorist group kidnapped a newborn baby from a hospital. I asked
four mothers if they would approve of torturing kidnappers if that were
necessary to get their own newborns back. All said yes, the most ‘liberal’ adding
that she would like to administer it herself.
I am not advocating torture as punishment. Punishment is addressed to
deeds irrevocably past. Rather, I am advocating torture as an acceptable
measure for preventing future evils. So understood, it is far less objectionable
than many extant punishments. Opponents of the death penalty, for example,
are forever insisting that executing a murderer will not bring back his victim (as
if the purpose of capital punishment were supposed to be resurrection, not
deterrence or retribution). But torture, in the cases described, is intended not
to bring anyone back but to keep innocents from being dispatched. The most
powerful argument against using torture as a punishment or to secure
confessions is that such practices disregard the rights of the individual. Well, if
the individual is all that important – and he is – it is correspondingly important
to protect the rights of individuals threatened by terrorists. If life is so valuable
that it must never been taken, the lives of the innocents must be saved even at
the price of hurting the one who endangers them.
Better precedents for torture are assassination and pre-emptive attack.
No Allied leader would have flinched at assassinating Hitler, had that been
possible. (The Allies did assassinate Heydrich.) Americans would be angered to
learn that Roosevelt could have had Hitler killed in 1943 – thereby shortening
the war and saving millions of lives – but refused on moral grounds. Similarly, if
nation A learns that nation B is about to launch an unprovoked attack, A has a
right to save itself by destroying B’s military capability first. In the same way, if
the police can by torture save those who would otherwise die at the hands of
kidnappers or terrorists, they must.
Levin 1983: “The Case for Torture”
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Idealism: There is an important difference between terrorists and their
victims that should mute talk of the terrorists’ “rights.” The terrorist’s victims
are at risk unintentionally, not having asked to be endangered. But the terrorist
knowingly initiated his actions. Unlike his victims, he volunteered for the risks
of his deed. By threatening to kill for profit or idealism, he renounces civilized
standards, and he can have no complaint if civilization tries to thwart him by
whatever means necessary.
Just as torture is justified only to save lives (not exhort confessions or
recantations), it is justifiably administered only to those known to hold
innocent lives in their hands. Ah, but how can the authorities ever be sure that
they have the malefactor? Isn’t there a danger of error and abuse? Won’t We
turn into Them?
Questions like these are disingenuous in a world in which terrorists
proclaim themselves and perform for television. The name of their game is
public recognition. After all, you can’t very well intimidate a government into
releasing your freedom fighters unless you announce that it is your group that
has seized its embassy. ‘Clear guilt’ is difficult to define, but when 40 million
people see a group of masked gunman seize an airplane on the evening news,
there is not much question about who the perpetrators are. There will be hard
cases where the situation is murkier. Nonetheless, a line demarcating the
legitimate use of torture can be drawn. Torture only the obviously guilty, and
only for the sake of saving innocents, and the line between Us and Them will
remain clear.
There is little danger that the Western democracies will lose their way if
they choose to inflict pain as one way of preserving order. Paralysis in the face
of evil is the greater danger. Some day soon a terrorist will threaten tens of
thousands of lives, and torture will be the only way to save them. We had better
start thinking about this.
Levin 1983: “The Case for Torture”
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A Little Bit of Logic
by Louis Pojman, 2006
American Philosopher, 1935-2005
Basics of Argument Analysis
Philosophy is centered in the analysis and construction of arguments. We call
the study of arguments logic. Let us devote a little time to the rudiments of
logic. By argument we do not mean a verbal fight but a process of supporting
a thesis (called the conclusion) with reasons (called premises). An argument
consists of at least two declarative sentences (sometimes called propositions),
one of which (the conclusion) logically follows from the others (the
premises).The connection by which the conclusion follows from the premises
is called an inference:1
1
Pojman’s original diagram is similar but wouldn’t transfer to Word neatly. It is meant to depict
that, from proposition 1 and proposition 2 combining, they serve as premises from which
another proposition can be concluded.
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[Arguments come in perhaps three basic varieties: Deductive, Inductive, and
Abductive reasoning. All three have various sub-varieties. They are evaluated
slightly differently from one another.]
Deductive Reasoning
A valid deductive argument is one that follows a correct logical form, so that if
the premises are true, the conclusion must also be true. If the form is not a good
one, the argument is invalid. We say that a valid deductive argument preserves
truth. It does so in much the same way as a good refrigerator preserves food.
If the food is good, a good refrigerator will preserve it; but if the food is already
spoiled, the refrigerator will not make it good. The same is true with the
premises of a valid argument. If the statements are true and the form is correct,
the conclusion will be true; but if the premises are not true, a valid argument
will not guarantee a true conclusion. [Note that a deductive argument can be
valid but have false premises. A deductive argument can also have true
premises but be invalid.]
A classic example of a valid argument is the following:
1. Socrates is a man. [Premise]
2. All men are mortal. [Premise]
3. So, Socrates is mortal. [Conclusion]
To identity the form, let us look at conclusion (3) and identity the two
major components: a subject (S) and a predicate (P). Socrates is the subject
term, and mortal is the predicate term. Now return to the two premises and
identity these two terms in them. We discover that the two terms are
connected by a third term, man (or the plural men). We call this the middle term
(M).
The form of the argument is as follows:
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1. S is M.
2. All M are P.
3. So, S is P.
This is an example of a valid deductive form. If premises (1) and (2) are
true, we will always get a true conclusion by using this form. But notice how
easy it would be to get an invalid form. Change the order of the second premise
to read” All P are M.” Let the first premise read “My roommate is a mammal”
and the second premise read “All dogs are mammals.” What do you get?
1. My roommate, Sam Smith, is a mammal.
2. Dogs are mammals.
3. So, my roommate is a dog.
Regardless of how badly you might treat your roommate, the argument
has improper form and cannot yield a valid conclusion; it is invalid. Every
argument is either valid or invalid. Like a woman who cannot be a little pregnant,
an argument cannot be partly valid or invalid but must be completely one or the
other. By seeking to find counterexamples for argument forms, we can discover
which are the correct forms. (A full study of this requires a course in logic.)
Validity is not the only concept we need to examine; soundness is also
important. An argument can be valid but still unsound. An argument is sound if
it has a valid form and all its premises are true. If at least one premise is false,
the argument is unsound. Here is an example of a sound argument:
1. If Mary is a mother, she must be a woman.
2. Mary is a mother (for she has just given birth to a baby).
3. So, Mary is a woman.
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If Mary hasn’t given birth, then premise (2) is false, and the argument is
unsound [but still valid].
You should be aware of four other deductive argument forms: modus
ponens, modus tollens, disjunctive syllogism, and reductio ad absurdum. Here are
their forms:
Modus Ponens (MP) (Affirming the Antecedent)
1. If P, then Q.
2. P.
3. So, Q.
Modus Tollens (MT) (Denying the Consequent)
1. If P, then Q.
2. Not-Q.
3. So, Not-P.
Note in a hypothetical proposition (if P, then Q) the first term (the proposition
P) is called the antecedent and the second term (Q) the consequent. Both
affirming the antecedent and denying the consequent yield valid forms.
Disjunctive Syllogism (DS) (Denying the Disjunct)
1. Either P or Q.
2. Not-Q. 3.
3. So, P.
Reductio ad Absurdum (RAA) (Reducing to a Contradiction)
1. Assume A. (A is the logical opposite of the conclusion you seek to
prove.)
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2. Logically deduce a contradiction from A. (This shows that A implies a
contradiction.)
3. This proves A is false, since a contradiction cannot be true. So not-A
must be true.
We have already given an example of a modus ponens:
1. If Mary is a mother, she must be a woman.
2. Mary is a mother.
3. So, Mary is a woman.
Here is an example of a modus tollens:
1. If Leslie is a mother, she is a woman.
2. Leslie is not a woman (but a man).
3. So, Leslie is not a mother.
Here is an example of a disjunctive syllogism (sometimes called “denying the
disjunct” – a disjunct refers to a proposition with an “or” statement in it, such
as “P or Q”):
1. John is either a bachelor or a married man.
2. We know for certain that John is not married.
3. So, John is a bachelor.
We turn now to reductio ad absurdum (RAA). This is an indirect method of
proving or establishing a thesis. You assume the opposite of what you wish to
prove and show that it produces an absurd conclusion. Therefore, your thesis
must be true. Here is an example of an RAA; a little more complicated than the
other forms… Suppose someone denies that there is such a thing as a self and
you wish to refute the assertion. You might argue in the following manner:
1. Suppose you’re correct and there is no such thing as a self (not-A).
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2. But if there is no such thing as a self, then no one ever acts (if not-A, then
not-B).
3. But if no one ever acts, then no one can utter meaningful statements (if
nor-B, then not-C).
4. But you have purported to utter a meaningful statement in saying that
there is no such thing as a self, so there is at least one meaningful
statement (C).
5. According to your argument, there is and there is not at least one
meaningful statement (C and not-C).
6. It must be false that there is no such thing as a self (not, not-A – which
by double negation yields A). Thus, we have proved by reductio ad
absurdum that there is such a thing as a self.
Before we leave the realm of deductive argument, we must point out two
invalid forms that often give students trouble. To understand them, look back
at forms MP and MT, which respectively argue by affirming the antecedent and
denying the consequent. But notice that there are two other possible forms.
You can also deny the antecedent and affirm the consequent in the following
manner:
Denying the Antecedent (DA)
1. If P, then Q.
2. Not-P.
3. So, Not-Q.
Affirming the Consequent (AC)
1. If P, then Q.
2. Q. 3.
3. So, P.
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Are these valid forms? Remember a valid form must always yield true
conclusions if the premises are true. Try to find a counterexample that will show
that these two forms are invalid. You might let proposition 1 (if P, then Q) be
represented by the previous proposition, “If Mary is a mother, then she is a
woman.” First, deny the antecedent. Does it necessarily yield a true conclusion?
Not necessarily. The conclusion says that Mary is not a woman, but there are
many women who are not mothers. So DA is an invalid form.
1. If Mary is a mother, she is a woman.
2. Mary is not a mother.
3. So, Mary is not a woman.
Take the same initial proposition and affirm the consequent “Mary is a woman.”
Does this in itself yield the conclusion that she is a mother? Of course not. She
could be a woman without being a mother:
1. If Mary is a mother, she is a woman.
2. She is a woman.
3. So, Mary is a mother.
Thus, whereas MP and MT are valid forms, DA and AC are not. Be careful here.
Many students slur over these distinctions. Work out your own examples of
each form of argument. These are just simple examples of deductive argument
forms. Often, alas, it is difficult to state exactly what the author’s premises are.
Inductive Reasoning
Let us turn our attention to inductive arguments. Unlike their counterpart, valid
deductive arguments, inductive arguments are not truth-preserving – that is,
they do not guarantee that if we have true premises, we will obtain a true
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conclusion. They bring only probability; but in most of life, that is the best we
can hope for. David Hume (1711-1776) said that “probability is the guide of life.”
The wise person guides his or her life by the best evidence available, always
realizing that one could be mistaken. We usually do not speak of inductive
arguments as valid / invalid or sound / unsound but as strong / weak or
[plausible]/ implausible. In inductive arguments, the premises are evidence for
the conclusion or hypothesis. If the evidence for the conclusion is substantial,
we call the argument a strong inductive argument; but if the evidence is weak,
so is the argument as a whole. An inductive argument has the following form:
1.
2.
3.
4.
A1 is a B.
A2 is a B.
A3 is a B.
So, probably the next A we encounter (A4) will also be a B.
For example, suppose you are surrounded by four islands somewhere in the
Pacific Ocean. You examine all trees on three of the islands but cannot get to
the fourth. Nevertheless, you might make some predictions on the basis of your
experience on the first three islands. For example, you note that all trees on
islands A, B, and C are coconut trees. From this you predict that coconut trees
will be on island D and that coconut is probably the only tree found there.
We learn from experience, that is, by induction. We observe resemblances
and regularities in life and generalize from them. After a few experiences of
getting burned by fire (or after a few experiences with people of a certain type),
we learn to avoid fire (or people of a certain type). The human race has learned
by inductive experience that cooperation generally produces more benefits
than noncooperation, so we advocate cooperative ventures.
Naturally, the greater the sample size of our observation, the greater the
probability of our generalization. Asking 1,000 representative Americans whom
they will vote for is likely to yield a more accurate prediction of who will be
elected than asking only 100 Americans. Sometimes, when we should know
better, we generalize or make predictions from an inadequate sample; we call
this prejudice, a type of malformed induction. If a child infers from his only six
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bad experiences with people from Podunkville that all people in Podunkville are
bad, that might be acceptable. However, if an adult, who could easily have
evidence that many good people live in Podunkville, still generalizes about the
people of Podunkville and acts accordingly, we label this an irrational bias, a
prejudice.
Inductive reasoning can lead us astray – it can be dangerous. The
chicken who innately reasons that the farmer will feed her again today because
he has done so twice a day for a long time is in for a cruel shock when he wrings
her neck in preparation for his meal. [Nonetheless, this does not mean inductive
reasoning is bad reasoning; it is absolutely necessary in order to live a rational
life, and it can go well or poorly.]
A special kind of inductive reasoning is called reasoning by analogy.
Reasoning by analogy allows us to reason from the similarity of two things in some
relevant respects to their similarity in an unexpected respect. For example,
suppose I am lost in the forest and I want to determine whether to eat a certain
mushroom, which my hungry stomach craves. I note that it is similar in shape,
color, and consistency with other mushrooms that turned out to be edible.
Thus, I infer that probably this mushroom will be edible too. [Like inductive
reasoning, this kind of reasoning can go both well or poorly. Good analogical
inductive arguments generally state many different kinds of relevant similarities
between the target phenomenon and the analog, and may also compare the
target phenomena with several diverse analogs as well. Poor analogical
arguments, by contrast, tend to lack these features.]
Abductive Reasoning
Abductive reasoning, or reasoning to the best explanation, was first formulated
by the American philosopher Charles S. Peirce (1839-1914). Like inductive
reasoning, abduction yields only probable truth. Whereas induction establishes
general premises or probabilities about future occurrences, abduction provides
explanatory hypotheses. It answers the question, Why is such and such the case?
We can illustrate abductive reasoning with the following example of Sherlock
Holmes’s reasoning:
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The portly client puffed out his chest with an appearance of some little
pride and pulled a dirty and wrinkled newspaper from the inside pocket of
his great coat. As he glanced down the advertisement column with his
head thrust forward and the paper flattened out upon his knee, I took a
good look at the man and endeavored, after the fashion of my companion,
to read the indications which might be presented by his dress or
appearance.
I did not gain very much, however, by my inspection. Our visitor
bore every mark of being an average commonplace British tradesman,
obese, pompous, and slow He wore rather baggy gray shepherd’s check
trousers, a not over-clean black frock-coat, unbuttoned in the front, and a
drab waistcoat with a heavy brassy Albert chain, and a square pierced bit
of metal dangling down as an ornament. A frayed top-hat and a faded
brown overcoat with a wrinkled velvet collar lay upon a chair beside him.
Altogether, look as I would, there was nothing remarkable about the man
save his blazing red head and the expression of extreme chagrin and
discontent upon his features.
Sherlock Holmes’s quick eye took in my occupation, and he shook
his head with a smile as he noticed my questioning glances.” Beyond the
obvious facts that he has at some time done manual labor, that he takes
snuff, that he is a Freemason, that he has been in China, and that he has
done a considerable amount of writing lately, I can deduce nothing else,”
Mr. Jabez Wilson started up in his chair, with his forefinger upon the paper,
but his eyes upon my companion.
“How, in the name of good-fortune did you know all that, Mr.
Holmes?” he asked. “How did you know, for example, that I did manual
labor? It’s as true as gospel, for I began as a ship’s carpenter.”
“Your hands, my dear sir. Your right hand is quite a size larger than
your left. You have worked with it, and the muscles are more developed.”
“Well, the snuff, then, and the Freemasonry?”
“I won’t insult your intelligence by telling you how I read that,
especially as, rather against the strict rules of your order, you use an arcarid-compass breastpin,”
“Ah, of course, I forgot that. But the writing?”
“What else can be indicated by that right cuff so very shiny for five
inches, and the left one with the smooth patch near the elbow where you
rest it upon the desk?”
“Well, but China?”
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“The fish which you have tattooed immediately above your right
wrist could only have been done in China. I have made a small study of
tattoo marks and have even contributed to the literature of the subject.
That trick of staining the fishes’ scales of a delicate pink is quite peculiar to
China. When, in addition, I see a Chinese coin hanging from your watch
chain, the matter becomes even more simple.”
Mr. Jabez Wilson laughed heavily. “Well, I never!” said he. “I
thought at first that you had done something clever, but I see that there
was nothing in it, after all.”
Philosophers appreciate Mr. Wilson’s final remark, that Holmes’s
explanation makes so much sense that one wonders why one didn’t think of it
oneself. Holmes often chided Watson: “You see, but you do not observe.” A
good philosopher, like a good detective or scientist, observes while he or she
sees.
There is a significant inaccuracy, however, in Holmes’s description of
what he does. He claims to be deducing the conclusions about Mr. Wilson from
the telltale signs. Strictly speaking, he is doing no such thing. In deductive
reasoning, if the form is correct and the premises are true, one cannot help but
obtain a true conclusion, but such is not the case with ·Mr. Holmes’s reasoning.
For example, consider Wilson’s arc-and-compass breastpin, which leads Holmes
to conclude that Wilson is a Freemason. If the reasoning were deductive, the
argument would go something like this:
1. Everyone wearing an arc-arid-compass breastpin is a Freemason.
2. Mr. Wilson is wearing an arc-and-compass breastpin.
3. So, Mr. Wilson is a Freemason.
Is this a sound argument? Of course not. Imagine that Mr. Wilson, who is not a
Freemason, bought a similar arc-and-compass breastpin at a pawnshop and
wore it, thinking it was a beautiful bit of Muslim design. In that case, premise 1
would be false. Not everyone wearing an arc-and-compass breastpin is a
Freemason. Because it is possible that non-Freemasons wear that pin, the
above deductive argument is not sound.
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What Holmes has really done is reason abductively, that is, reason to the
best explanation of the facts. Like inductive reasoning; abduction does not
guarantee the truth of the conclusions. Unlike induction it is not simply about the
probability of such and such being the case based on the evidence. Abductive
reasoning attempts to offer explanations of the facts, why things are the way they
are. The best explanation of Mr. Wilson’s wearing the arc-arid-compass
breastpin is his belonging to the Freemasons. The best explanation of a child’s
having a fever and red spots is that she has the measles. The best explanation
of the puddles outside is that it has recently rained.
The notion of the best explanation is fascinating in its own right. How do
we discover the best explanation? What characteristics does it have? How do
we rank various virtues of a good explanation? There are no definite answers to
these questions, but it is generally agreed that such traits as predictability,
coherence, simplicity, and fruitfulness are among the main characteristics. If a
theory helps us predict future events, that is a powerful weapon. If it coheres
well with everything or nearly everything else that we hold true in the field, that
lends support to it. If it is simpler than its rivals, if it demands fewer ad hoc, or
auxiliary, hypotheses, that is a virtue. If it leads to new insight and discoveries,
that is also a point in its favor. But what if explanatory theory A has more of one
of these features and theory B more of another? Which should we prefer? There
is no decision making procedure to decide the matter with any finality In a
sense, abduction is educated guesswork or intuition. Counterevidence counts
strongly against a hypothesis, so that if we can falsify our thesis, we have good
reason to drop it; however, sometimes we can make adjustments in our
hypothesis to accommodate the counterevidence.
Abduction has been neglected in philosophy, but it really is of the
utmost importance. Consider the following questions: Why do you believe in
God? Why do you believe in evolutionary theory? Why do you believe that’ there
are universal moral principles? Why do you believe that all events are caused?
In one way or another, the answer will probably be abductive: What you believe
seems to you to be the best explanation among all the competitors of certain
phenomena. We will have opportunity to use abductive reasoning at several
points during our course of study.
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Philosophical Applications of Logic
Let’s apply these brief lessons of logic to reading philosophy. Because the key to
philosophy is the argument, you will want to concentrate and even outline the
author’s reasoning. Find his or her thesis or conclusion. Usually, it is stated early
on. After this, identify the premises that support or lead to the conclusion. For
example, Thomas Aquinas (1224-1274) holds the conclusion that God exists. He
argues for this conclusion in five different ways. In the second argument, he
uses the following premises to reach his conclusion: There is motion, and there
cannot be motion without something initiating the motion.
It helps to outline the premises of the argument. For example, here’s how
we might set forth Aquinas’s second argument:
1. Some things are in motion. [Premise]
2. Nothing in the world can move itself but must be moved by another.
[Premise]
3. There cannot be an infinite regress of motions. [Premise]
4. There must be a First Mover who is responsible for all other motion.
[Conclusion of premises 1-3,which in turn becomes a premise for the rest
of the argument]
5. This First Mover is what we call God (explanation of the meaning of
God). [Premise]
6. So, God exists. [Conclusion of second part of the argument, premises 4
and 5]
After you have identified the premises and conclusion, analyze them,
looking for mistakes in the reasoning process. Sometimes arguments are weak or
unsound, but not obviously so. Then stretch your imagination and think of
possible counterexamples to the claims of the author. I found this process almost
impossible at first, but gradually it became second nature.
Because philosophical arguments are often complex and subtle (and
because philosophers do not always write as dearly as they should), a full
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understanding of an essay is not readily available after a single reading. So read it
twice or even thrice. The first time I read a philosophy essay, I read it for
understanding. I want to know where the author is coming from and what he
or she is trying to establish. After the first reading, I leave the essay for some
time, ruminating on it. Sometimes objections to the arguments awaken me at
night or while I am working at something else. Then I go back a day or so later
and read the essay a second time, this time trying to determine its soundness.
A few pointers should be mentioned along the way. Some students find
it helpful to keep a notebook on their reflections on the readings. [When reading
through the essays, print them, and] I suggest that you make notes in the marginsinitially in pencil because you may want to revise your impressions after a second
reading. Finally, practice charity. Give the author the best possible interpretation
in order to see if the argument has merit. Always try to deal with the most
generous version of the argument, especially if you don’t agree with its
conclusion. A position has not been seriously challenged unless the best
arguments for it have been refuted. That’s why it is necessary to construe all
arguments, including those of your opponents, as charitably as possible. The
exercise will broaden your horizons and help you develop sharper reasoning
skills.
Argumentative Fallacies
Before we sum up this chapter, I would like to identify a number of common
fallacies of reasoning [alone, by especially within the context of debate]. Good
reasoning depends on justified beliefs (acceptable premises) and valid logical
form. Many arguments, however, fail to satisfy these conditions. I have listed
some of the main fallacies of reasoning. See if you can illustrate them with
examples of your own.
▪
Ad Hominem Argument. This is an argument “against the man.” This
argument attacks the person instead of the position-for example, “You
can’t trust what Joan says about abortion, for she is an immoral person.”
Her argument for or against abortion, however, may be sound on
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independent grounds. Even the devil has true beliefs. The character of
the person is irrelevant to the soundness of the argument.
▪
Argument from Authority. Suppose we are arguing about the death
penalty, and I tell you that we should believe in the death penalty
because Plato believed in it. Since you don’t know Plato’s reasons (I may
not either), it is not sufficient grounds for either of us to believe in the
death penalty. We need positive arguments, not simply authority.
Advertisements are notorious for subtly and sometimes not so subtly
using this device. In a beer commercial, a famous athlete (nicely
remunerated for the exercise) may be seen gratifying his thirst,
proclaiming the ecstasy of the beverage, as if that were proof of its
quality. Of course, authority may sometimes be the best we can get and
sufficient for justified belief, as when a physicist tells us the conclusions
of complicated physics research or a friend from Australia gives you
pertinent information for your upcoming visit to that country. We
sometimes do need to trust authority, but often it is an improper
substitute for good reasoning.
▪
Arguing in a Circle. This is sometimes referred to as “begging the
question.” Suppose I argue that you should believe that God exists. You
ask why. I say, “Because the Bible says so / You ask, “Why should I
believe what the Bible says?” I reply, “Because it’s the Word of God.”
That is, I argue in a circle, using my conclusion as a premise to prove the
conclusion. Note that all valid deductive arguments can appear as
arguing in a circle, since the conclusion of such an argument is contained
in the premises. The difference is that in a cogent argument the
conclusion brings out a nontrivial feature of the premises. Essentially,
arguing in a circle is not invalid, just trivial and unconvincing, having no
power to convince an opponent.
▪
Argument from Ignorance. This kind of argument occurs when I claim
that, because you cannot prove a proposition is false, I am justified in
believing it to be true. For example, because you can’t prove God
doesn’t exist, I am free to believe that He does exist; or because you
can’t prove that we do not have a soul, I am free to believe that we do.
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▪
False Dilemma. This happens when we reduce several possibilities (Q
two alternatives. I once read of two travelers facing a swamp in which
traveler A said to traveler B, “Since you admit you don’t know the way
through the swamp and there must be a way, follow me. I must know
the way.” Of course, neither may know the way. Similarly, someone may
argue that since your answer to a problem isn’t correct, his or hers must
be. But, of course, both may be wrong.
▪
Slippery Slope. This is sometimes called the “edge-of-the-wedge”
argument (once you let the camel’s nose under the wedge of the tent,
it will capsize the entire tent). Similarly, it will be argued, once we allow
act A to occur, event B, which is evil, will occur. Robert Wright has
argued that “once you buy the premise that animals can experience pain
and pleasure, and that their welfare therefore deserves some
consideration, you’re on the road to comparing yourself with a lobster.
There may be some exit ramps along the way-plausible places to
separate welfare from rights-but I can’t find any.” Others have argued
that if we allow voluntary euthanasia, we are on the slippery slope to
involuntary euthanasia, even eventually to a holocaust. Still others have
argued that if we pass a national health care bill, it will inevitably lead to
socialism and communism. The slippery slope fallacy ignores the truth
that, very often, wise policy is a moderate stance between two
extremes and that rational people can hold to a rational position
without going to an extreme.
▪
Straw Man Argument. This is an instance of misrepresenting an
opponent’s position. It occurs when someone ignores the evidence for
a position and instead attacks an inferior version of the position. In the
heat of debate on whether our nation should reduce its military
spending, a militarist may argue that his opponent wants to leave our
nation defenseless or a willing prey to communism. I once heard of a
Russian tourist guide who claimed that she knew that God didn’t exist,
because if he did, he would announce his presence from heaven. The
straw man argument is often a distortion of the other person’s position.
There is a tendency in all of LIS to attack a weaker-less plausible—version
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of our opponent’s position. The principle of charity is the opposite of the
straw man argument. It instructs us to give our opponent’s position the
very best form we can find-and then try to show it is unsound.
▪
Genetic Fallacy. This is arguing against a position or argument because
its origins are suspect. Suppose I tell you not to believe in the principles
of chemistry because they originated in superstitious alchemy or not to
believe in an astronomical theory because it arose from astrological
sources. The fact that a theory or position originated in discredited
circumstances is irrelevant if the theory is supported by the evidence.
For their theories, chemistry and astronomy can produce impressive
evidence that is independent of the authority of alchemy and astrology.
It doesn’t matter where the truth comes from, as long as it is true.
▪
Inconsistency. When we argue inconsistently, we argue from
contradictory premises. When trying to win votes from one
constituency, politicians sometimes contradict what they have said to
other constituencies. To illustrate this, consider some statements made
by former President Ronald Reagan at different periods of his political
career:
“I favor the Civil Rights Act of 1964 and it must be enforced at the
point of a bayonet, if necessary” (October 19, 1965).
“I would have voted against the Civil Rights Act of 1964” (June
16,1966).
“I believe our country can and should have a Redwood National
Park in California” (April 17, 1967).
“There can be no proof given that a national park is necessary to
preserve the redwoods. The state of California has already
maintained a great conservation program” (April 18, 1967-the
next day).
“I just don’t believe the farmers should be made to pay a special
price for our diplomacy, and I’m opposed to [the Soviet grain
embargo]” (January 7, 1980).
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“If we are going to do such a thing to the Soviet Union as a full
grain embargo, which I support, first we have to be sure our own
allies would join us on this” (January 8, 1980-the next day).
Of course, people change their minds and come to believe the opposite
of what they formerly believed. That may show progress, but many of
us are not aware of the inconsistencies in our own belief systems. For
example, Fred may believe that morality entails universalizing principles
(“what’s good for the goose is good for the gander”) but fail to note
that his view on premarital sex-morally permissible for men but not for
women-is inconsistent with that principle.
Necessary and Sufficient Conditions
One logical relationship that will appear throughout [the readings in the
course] deserves to be highlighted now. Sometimes we speak of A being a
necessary condition for B, or of B being a sufficient condition for A, or of A and
C being necessary and sufficient conditions for B. Sometimes these terms refer
to causal relationships. For example:
1. Cutting off a person’s head is sufficient to kill him. Cutting off someone’s
head is not a necessary condition for killing someone (there are other
equally effective ways), but it will get the job done.
On the other hand, we might read that:
2. Grandma’s will states that her death is necessary for the grandchildren
to inherit her estate. That is, the grandchildren will inherit Grandma’s
estate only if she dies. But Grandma’s death may not be a sufficient
condition for such an inheritance, for her will may stipulate other
conditions that must be fulfilled, such as that all outstanding bills be
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paid, that the grandchildren remain Southern Baptists, and that the
grandchildren refrain from drinking alcoholic beverages. If these are the
only conditions for inheriting her estate, we might formulate the
complete necessary and sufficient conditions in terms of a statement
containing the phrase “if and only if”: The grandchildren will inherit
Grandma’s estate if and only if (a) Grandma dies, (b) all outstanding bills
are paid from the estate and funds are left, (c) the grandchildren remain
members of the Southern Baptist Church, and (d) they refrain from
drinking alcoholic beverages. Conditions a-d are necessary and jointly
sufficient for inheriting Grandma’s estate. If only some of the conditions
obtain (are realized), this is not sufficient for inheriting the estate, but if
we discover that the estate has been inherited, we can infer that all
conditions have obtained. That the estate was passed down to the
grandchildren is sufficient for us to know that the four conditions were
fulfilled.
3. The idea of necessary and sufficient conditions is sometimes applied to
definitions, as in “A means B.” Suppose we define a mother as a female
who has given birth to a child. We may spell this out this way: mother =
a female who has given birth to an offspring.
We may also say of any person X, “X is a mother if and only if X is a female and
has given birth to an offspring.” Breaking this down, we find:
a. A is a necessary condition for B means that if B is true, then A is
true: Being a female and having given birth are two necessary
conditions for being a mother.
b. A is a sufficient condition for B means that if A is true, then B is
true: Being a mother is a sufficient condition for being a woman
who has given birth to an offspring.
Putting the two together, we get:
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c. A is a necessary and sufficient condition for B means that if A is
true, B is and if B is true, A is: If Mary is a mother, then she is a
woman who has given birth, and if she is a woman who has given
birth, she is a mother.
4. Some person X knows that p (where p stands for a proposition) if and
only if
a. X believes p.
b. P is true.
c. X’s belief that p is justified.
Conditions a-c are necessary and jointly sufficient conditions for
knowledge. Similarly, the truth of the first part of the conditional “X
knows that p” is sufficient for us to know that conditions a-c have been
fulfilled. However, proposition 4 may not be a completely adequate
definition of the term knowledge. It’s a disputed matter.
[Philosophers often represent the relation of necessity and sufficient, if and
only if, by “iff.” If you see this in the readings, that is what is means: A iff B = if
A, then B, and if B, then A.]
Summary
[Arguments are composed of premises, conclusions, and relations of inference
connecting them. There are three main kinds of argument: Deductive,
Inductive, and Abductive.] In a valid deductive argument, if the premises are
true, the conclusion must be true by virtue of a logically necessary form. In a
strong inductive argument, the premises, if true, make the conclusion probable
but do not guarantee the truth of the conclusion. In a [strong] abductive
argument, the conclusion or hypothesis offers the best explanation of the data.
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Introduction to Philosophical Reasoning
Andrew D. Bassford, 2021
Professor of Philosophy, Austin Community College
Direct and Indirect Evidence1
The world is a certain way, regardless of how we think about it. As we go
through life, we form mental representations of it and its objects around us.
Some of those representations may adequately correspond to reality, and
some may not. Those that do are said to be true; those that do not, false. We
call these representations our beliefs. We want our beliefs to be true. True
beliefs tend to be more useful for navigating through reality than false ones.
For example, if I desire a sandwich and I believe the refrigerator contains
sandwiches, that will not only dictate my actions, but will make my actions
effective at attaining my desires. Desires without beliefs are unfulfillable
through my actions. Moreover, we also like knowledge for its own sake. We’d
all rather be connected to reality than some mere illusion, however comforting.
Unfortunately, it is not always easy to tell the true beliefs from the false ones.
So, how can we determine whether our representations of the world accurately
correspond to it or not?
Beliefs are verified or falsified by evidence. There are two basic types of
evidence: direct evidence and indirect evidence. There are some beliefs that can
be verified or falsified simply by observation. This is a form of direct evidence.
You can tell whether or not it is raining simply by looking outside. You can tell
whether the bath water is warm by putting your hand in it. We not only form
some of our beliefs in this way, but we also directly justify them in this way too.
But not every belief can be verified or falsified via observation. Some beliefs can
only be verified or falsified indirectly. For example, how do you know what year
1
This section quotes extensively from David Kelley’s (1998) chapter, “Basic Argument
Analysis,” from his The Art of Reasoning, Norton.
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you were born? Obviously, you did not witness your own birth. You were told
about it by your parents, who did experience the event, and you trust what they
told you. In the same way, you know that George Washington was the first
president of the United States because you learned it from a history teacher or
a textbook. In this case, neither the teacher nor the writer of the textbook
witnessed Washington’s presidency, any more than you did. But they learned
about it from other people, who learned it from still others, extending back in
a chain to people who were alive in 1788 and kept records at that time. We take
many beliefs to be verified or falsified in this way—by the indirect evidence of
testimony. Because we can communicate what we experience, human beings
can merge their separate representations of the world onto one giant canvas.
Testimony is one kind of indirect evidence. Still another important kind
of indirect evidence is reasoning. The basic idea of reasoning in general is that
we exploit the relationships among beliefs to extend our knowledge beyond
what we have experienced directly. Beliefs form complex truth-dependence
relationships with one another. Some beliefs are such that, if one of them is
true, so too must the other one. For example, if all men are mortal and Socrates
is a man, it must also be the case that Socrates is mortal too. Other beliefs are
such that, if one of them is true, the other must be false. For example, if Gerald
is a giraffe and no giraffe has gills, it must also be the case that Gerald does not
have gills either. And still others are such that, if one is true, the other one is
likely to be true (or false), as well. For example, if 1,000 samples of water have
boiled at 100 degrees Fahrenheit, it is likely that all water will boil at 100 degrees
Fahrenheit under similar conditions. Reasoning thus allows us to verify or falsify
beliefs which may transcend the collective experience of human beings
altogether. It is through the indirect evidence of reasoning, coupled with
observation, that we have learned about the origins of our planet, the reaches
of outer space, the inner life of atoms, and so on—none of which has been
directly observed by anyone.
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Argument Analysis
Just as beliefs may be true or false, so too reasoning may go well or poorly.
Logic is the philosophical science of good and bad reasoning. Logicians study
and codify good (and bad) truth-dependence relationships among beliefs into
basic general kinds. They have discovered many such patterns, both good and
bad, over the last few millennia. The basic unit of analysis in logic is the
argument. An argument is a set of beliefs (or statements), at least one of which
is taken to be true on the basis of the others. Another way to put this is that an
argument is some belief plus the reasons offered in its support. The belief that
is taken to be true on the basis of the others is called the argument’s conclusion.
The beliefs offered in support of the conclusion are called the argument’s
premises. The mental movement we make from the premises to the conclusion
is called the argument’s inference. In an argument, one infers the conclusion
from the premises. Although one often reasons from their own beliefs, one can
apply reasoning to any set of beliefs or statements. In this class, we will often
simply suppose that certain premises are true to see what follows from them.
Recognizing Arguments
Inference is the hallmark of every argument. Arguments are often expressed in
a series of written statements. If a passage of text contains an inference, its
function is to express an argument; otherwise, it has some different function.
For example, consider this passage:
Cable television can provide the viewer with more channels
than broadcast television, and it usually delivers a higher
quality picture. For these reasons, the number of cable
subscribers will probably continue to grow rapidly.
This passage expresses an argument. The premises of the argument are (1)
Cable television can provide the viewer with more channels than broadcast
television, and (2) Cable television usually delivers a higher quality picture than
broadcast television. On the basis of these claims, the author then make an
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inference to the conclusion that (3) The number of cable subscribers will
probably continue to grow rapidly. In other words, (1) and (2) are the reasons
why the author of the passage believes that (3) is true.
Passages of text can perform many functions; expressing an argument
is only one of them. For example, consider this passage, which does not express
an argument:
The first cable companies served remote rural communities.
These communities were too far from any broadcast station
to receive a clear signal over the air. Tall towers, usually
located on hills, picked up the signals and distributed them to
individual homes.
There are no premises or conclusions in this passage, because there is no
inference present. The author of this passage seems just to be recounting a
history of cable television. No belief here is taken to be true on the basis of any
of the others. Besides expressing arguments, passages of text can: recount a
history, advertise some product, plea for help, threaten, express a poem, tell a
story, praise a heroic act, and so on.
Passages of text that express arguments often use certain words that
signal to the reader that an argument is present, as well as how to identify its
major parts. Logicians call these indicator words. There are premise indicator
words and conclusion indicator words. Here are some common premise
indicator words: since, because, for, given that, assuming that, the reason is
that, in view of the fact that…etc. For example:
Since cable companies are now serving the suburbs and cities,
they pose a competitive challenge to broadcast television.
We can tell that there is an argument present here, because there is a premise
indicator word in front of the first part of the passage (“since”), signaling that
the author is taking some claim to be true on the basis of it. Now here are some
common conclusion indicator words: therefore, thus, so, consequently, as a
result, it follows that, hence, which implies that… etc. For example:
To be a lawyer, you need to be good at keeping track of
details, and Lonny is terrible at that, so he shouldn’t go into
law.
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We can tell that this passage expresses an argument too, because the final part
of it contains a conclusion indicator word (“so”), signally that it should be read
as the conclusion of a process of reasoning. These words and phrases are often
used in nonargumentative contexts too, such as when I say “I have been
studying philosophy since I was in high school,” or when I say “I have given you
this handout so that you can understand the basics of argumentation.” So, our
indicator words are not perfect. They are, nonetheless, reliable, and good
writers often use them to signal these purposes. You are encouraged to use
them in your own writing too.
Philosophy is a dialectical discipline, meaning philosophers conduct their
investigations through arguments. With practice, it will become easier to
identify when a passage contains an argument. There are, unfortunately, no
hard and fast rules for doing this.
Standard Form
In this course, we will encounter many arguments. The goal, in each case, is to
analyze and evaluate them, to determine whether their conclusion is worth
believing or not. To facilitate this process, we will frequently use what logicians
call standard form to represent our arguments. Standard form is a way of very
clearly presenting arguments. We begin by breaking up a complex passage into
its logically independent statements. (Usually, these will correspond to
individual statements, or statements within a compound sentence. But, as we
have seen, sometimes an argument can unfold over the course of a single
sentence.) We give each of those statements a number. We then list all of the
statements as a numbered list, putting the premises first and the conclusion
last. Next to every line containing a premise, we write in brackets “[Premise].”
Next to the conclusion, we write “[From…],” noting the lines from which the
conclusion has been inferred. An example will help elucidate this process.
Consider this passage, which contains an argument:
Welfare is a form of expropriation: it takes money out of one
person’s pocket and puts it into someone else’s. Since the
function of government is to protect individual rights,
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including property rights, it should not be running welfare
programs.
In this passage, there are three logically independent statements present: (1)
Welfare is a form of expropriation, (2) The function of government is to protect
individual rights, and (3) The government should not be running welfare
programs. Statements (1) and (2) are the premises, and statement (3) is the
conclusion. We can convert this passage into standard form like this:
1. Welfare is a form of expropriation. [Premise]
2. The function of government is to protect individual rights. [Premise]
3. The government should not be running welfare programs. [From (1) &
(2)]
Put this way, it is easier to understand how the argument is working. It is also
easier to evaluate the argument. We will return to that point in a moment.
Evaluating Arguments
Not all arguments are created equal. Some are very good, and some are very
bad. Every argument can be evaluated according to two criteria: the truth of
their premises, and the validity of their inferential force.
In a good argument, all of the premises are true, and the premises do in
fact support the conclusion. In this way, good arguments give us good reason
to believe their conclusion. Bad arguments, on the other hand, lack one of these
features. There are three ways an argument might fail to give us good reason
to believe its conclusion. First, the argument may contain a false premise. For
example:
1. All fish are mortal. [Premise]
2. Socrates is a fish. [Premise]
3. Therefore, Socrates is mortal. [From (1) & (2)]
Premise (2) of this argument is false. Socrates is not a fish, but a human being.
And so, here we have a bad argument. A second way an argument may fail to
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give us good reason is by containing premises which do not actually support
the conclusion. For example:
1. All fish are mortal. [Premise]
2. Socrates is mortal. [Premise]
3. Therefore, Socrates is a fish. [From (1) & (2)]
Both of the premises in this argument are true. However, the conclusion is
clearly false. This shows us that the premises of this argument do not actually
support the conclusion: Just because Socrates is mortal does not mean that
he’s a fish! Arguments with good inferential force are said to be valid;
arguments with bad inferential force, invalid.
And finally, some arguments are doubly bad—not only do they contain
false premises, but the premises do not even support the conclusion. For
example:
1. Only women can get pregnant. [Premise]
2. Socrates is a woman. [Premise]
3. Therefore, Socrates is pregnant. [From (1) & (2)]
This is clearly a terrible argument. Socrates is not a woman, but rather a man.
That’s the first problem. And the second problem with the argument is that,
even if both of the premises were true, it still would not follow that Socrates is
pregnant. The first premise says that only women can get pregnant; it does not
say that all women are pregnant, which is what it would need to state for the
argument to provide good reason for thinking that Socrates is pregnant. This
argument is therefore invalid, as well.
Good arguments are sometimes called sound. A sound argument is an
argument in which all of the premises are true, and in which the inferential force
of the argument is valid (i.e., the premises actually support the conclusion). Bad
arguments are unsound. An unsound argument is an argument in which either
one of the premises is false, or else the inferential force of the argument is
invalid (i.e., the premises do not actually support the conclusion). In reasoning,
we aim to produce only sound arguments.
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Simple and Complex Arguments
Some arguments are simple, and some are complex. In this course, we will
focus on simple arguments, but it is still good to discuss complex arguments,
since complex arguments are more familiar to us in daily life, and many of the
writings we will read in this class contain both simple and complex arguments.
A simple argument is an argument which contains only one inference.
That is, some reasons are presented in favor of some conclusion, and that is the
only act of reasoning contained within the passage: The premises of the
argument are assumed as true, and no argument is offered in support of them.
All of the examples we have looked at so far have been simple arguments, such
as this one:
To be a lawyer, you need to be good at keeping track of
details, and Lonny is terrible at that, so he shouldn’t go into
law.
Put into standard form, this argument looks like this:
1. To be a lawyer, you need to be good at keeping track of details.
[Premise]
2. Lonny is terrible at keeping track of details. [Premise]
3. Therefore, Lonny should not go into law. [From (1) & (2)]
This argument contains only one inference, and so is a simple argument. We
can tell that this is so because there is only one conclusion in the argument (line
3), signaled by only the one instance of “[From…]” in its standard form. The
premises here are simply taken to be true, and the author reasons on the basis
of them.
Other arguments are complex. A complex argument is an argument
which contains more than one inference. That is, some reasons are presented
in support of some conclusion, but the author does not simply assume that they
are true: They also offer an argument in support of one or more of the premises.
For this reason, complex arguments may be said to contain sub-arguments,
arguments embedded within the passage’s main argument. Here is an example
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of a complex argument, which is produced from modifying our previous
example:
To be a lawyer, you need to be good at keeping track of
details, but Lonny is terrible at that. Just yesterday, I asked
him to go to the grocery store to buy coconut milk, but he
bought regular milk instead. For these reasons, Lonny should
not go into law.
Put into standard form, this argument looks like this:
1. To be a lawyer, you need to be good at keeping track of details.
[Premise]
2. Just yesterday, I asked Lonny to go to the grocery store to buy coconut
milk, but he bought regular milk instead. [Premise]
3. Therefore, Lonny is terrible at keeping track of details. [From (2)]
4. Therefore, Lonny should not go into law. [From (1) & (3)]
As we can see, this argument contains two inferences, and so is a complex
argument. We can tell that this is so because there are two conclusions here
(lines 3 and 4), signaled by two instances of “[From…]” in its standard form.
Here, premise (1) is assumed without argument, but premise (3) is not: Line (3)
serves as both the conclusion of one argument and the premise of another. As
a result, this argument takes the form of a complex chain, where one link both
supports and is supported by another.
Authors often offer complex arguments whenever one of the premises
of their main argument is controversial. Almost every premise in philosophy
(especially moral philosophy) is controversial, and so complex arguments are
common. Whenever an argument is simple, it usually contains two premises
and only one conclusion. Logicians call simple arguments that take this form
syllogisms. Whenever an argument is complex, it may contain any number of
premises and conclusions. Complex arguments, however, can always be
represented as two or more simple arguments. For example, the previous
complex argument might also be represented like this:
1. Just yesterday, I asked Lonny to go to the grocery store to buy coconut
milk, but he bought regular milk instead. [Premise]
2. Therefore, Lonny is terrible at keeping track of details. [From (1)]
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3. To be a lawyer, you need to be good at keeping track of details.
[Premise]
4. Lonny is terrible at keeping track of details. [Premise]
5. Therefore, Lonny should not go into law. [From (3) & (4)]
Debates
Usually whenever people in ordinary life talk about “arguments,” they really
have in mind what logicians would call debates. An argument is a static, solitary
piece of reasoning. Debates, on the other hand, are dynamic and happen
between two reasoners (or between a reasoner and herself). Participants in a
debate are called interlocuters. We will enter into a debate with an author every
time we meet. Sometimes we will examine debates that already exist; other
times, we will examine debates that I have created for us; and still other times,
you will be asked to create a debate yourself. All of your writing assignments in
this class will ask you to construct a debate.
A debate occurs whenever an argument is presented and is then
critically challenged. As we know, there are two ways to challenge an
argument: One can either reject one of its premises, or one can reject the
inferential force of the argument. Both strategies would seek to show that the
initial argument is unsound. A challenge to an argument is called an objection.
The argument that one offers to show that either one of the initial argument’s
premises is false or otherwise that they do not actually support its conclusion
is called a critical argument, or a critique. Here is an example of a critique.
Suppose one is presented with the following argument:
Jerry will likely have difficulty in his computer science class this
semester. After all, he is not mechanically competent.
Put into standard form, this argument runs:
1. Jerry is not mechanically competent. [Premise]
2. Therefore, Jerry will likely have difficulty in his computer science class.
[From (1)]
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One might object to this argument by arguing that the premises do not actually
support the argument’s conclusion. For example, a critic might argue that:
But Jerry did well in computer science last semester.
Consequently, this argument gives us no good reason for
thinking Jerry will have difficulty in his computer science class
this semester.
Another way one might critique this argument is by denying that its premises
are true. In this case, there is only one premise in the argument. A critic might
argue that:
It’s false that Jerry is not mechanically competent. He built his
own stereo system last weekend, and anyone who can built a
stereo system is clearly not mechanically incompetent. So,
this argument gives us no good reason for thinking that Jerry
will struggle in his computer science class.
If either critical argument is sound, then the critic’s objection is successful and
the initial argument will have been shown to be unsound.
Authors do not often rest content once their arguments have been
critiqued. A defense is a reasoner’s critical response to a critique of their initial
argument. A reply is the author’s argument they offer to show that the
objection to their argument fails. For example, in response to the first critique
mentioned above, the author may reply that:
Jerry only did well in his computer science class last semester
because the class required mostly programming skills. Jerry is
indeed competent at programming. But this semester is
focused more on the hardware aspect of computer science,
and so will require some mechanical competence.
And in response to the second critique, the initial interlocuter may argue that:
It is true that Jerry built his own stereo last semester. But this
isn’t a testament to his mechanical competence: It has already
since malfunctioned.
If either reply succeeds, then the critique of the argument fails, and the defense
is successful.
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Critics, likewise, do not often rest content once their objections have
been rebutted. The result is that the conversation may continue on, with new
arguments offered in defense of the critique, and new critiques offered against
those defenses of the critique. A rejoinder is the critic’s critical response to their
initial author’s reply to the critique. A surrejoinder is the author’s critical
response to the critic’s rejoinder. Any given argument may evoke numerous
critiques, which may evoke numerous replies, which make evoke numerous
rejoinders, which may evoke numerous surrejoinders. The result is a complex
dialogue with many layers. Here is a schematic of a debate to help you keep the
terms in memory. Suppose there are two reasoners, Alfred and Bert:
A: Initial Argument
B: Critique
A: Reply
B: Rejoinder
A: Surrejoinder…
and so on. Each state in the conversation will contain an argument, and so, like
the initial argument, can be put into standard form and evaluated accordingly.
Sometimes students new to philosophy are confused as to why the
author of a text appears to contradict themselves so much. If you are reading a
text and you get this impression from it, this is most likely because the author
of the text is considering objections, replying to them, considering further
rejoinders, and so on. Philosophical writing is dialogical rather than linear. A
linear piece of writing advances from premises to some conclusion, and that is
it. It represents the thoughts of one reasoner alone. Dialogical writing, by
contrast, not only advances from premises to some conclusion or conclusions,
but it also stops along the way to consider and reply to potential objections.
Every piece of philosophical writing, in this way, contains a debate: a kind of
dialogue within a monologue. As you read through a philosophy essay, it may
be helpful to make notes in the margins to keep track of where you are in the
debate at any given moment. Whenever I read, I often add notes like “Reply 1”
or “Surrejoinder 2,” etc.
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Just as there are premise and conclusion indicator words, signaling to
you that a passage of text contains an argument, there are also debate indicator
words, signaling to you that the author of the text is considering a dissenting
voice. Common objection indicator words are: however, but, one might object
that, on the other hand, it might be said that… and so on. Common defense
indicator words are: in reply, on the contrary, in defense, to that I respond
that… and so on. With practice, it will become easier to identify when a passage
or series of passage contains a debate. But like argument identification, there
are, unfortunately, no hard and fast rules for identifying debates.
Critiques and Counterarguments
In a successful debate, an argument is presented and the critic critically
responds to it. In an unsuccessful debate, both reasoners end up talking past
one another. Another way to put this is that in a successful debate, the critic
offers a critique rather than a mere counterargument. A critique is an argument
that focuses on the initial argument and attempts to show why the argument
fails to rationally establish its conclusion. A counterargument, on the other
hand, is simply a new argument in favor of the opposite conclusion: It does not
actually engage with the initial argument at all. For example, were you to offer
an argument to the effect that the government should not be running welfare
programs, I would offer a critique if I were to focus on that argument and try
to undermine it, either by showing that one of your premises is false or that
they fail to prove the conclusion. I would have only offered a counterargument
if instead I simply offered a new argument for why the government should be
running welfare programs. There is a place in debates for both
counterarguments and critiques, but we need to be careful to not confuse the
two.
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Eristical and Dialectical Debates
Many people do not like engaging in debates, because they dislike what they
perceive to be the inherently hostile and adversarial nature of them. There are
two kinds of debate. One of them is, indeed, very nasty, and one is right to avoid
them. The other, however, is not and is often very pleasant and intellectually
stimulating.
An eristical debate is the kind of debate that occurs between
adversaries—the kind which is characteristic of the presidential debates or the
courtroom. In an eristical debate, the participants present their case before a
judge with the goal of convincing the judge that they are right and their
opponent is wrong, or otherwise that they should be chosen for some special
favor over their opponent. Eristical debates may be thought of as intellectual
wrestling matches. Interlocuters in an eristical debate will often use any means
at their disposal to achieve their desired outcome, including appealing to
emotion, appealing to authority, making fun of their opponent, changing the
subject, and so on.
A dialectical (or forensic) debate, on the other hand, is not adversarial
but fundamentally cooperative. In a dialectical debate, the participants
consider an issue together and each agree to adopt opposing stances with the
goal that, by critically discussing the best arguments in favor of each position,
the strongest position will prevail. Together, they come up with the best
objections and replies to their arguments, and they do not mind if the position
they have chosen turns out to be the false one. Whereas in eristical debates,
the desired outcome for each participant is victory, in dialectical debates, the
desired outcome for both participants is truth. Any move that persuades a
judge is permissible in eristical debates, but only moves that present genuine
evidence are permissible in dialectical debates. That is, interlocuters may appeal
to direct observation, testimony, science, mathematics, and so on.
Philosophical discourse is intended to be dialectical, not eristical.
Some of you may be familiar with the notion of an appeal in
argumentative writing, a concept which is often taught in introductory
composition courses. An appeal is used in those contexts to refer to whatever
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Page 14 of 15
the author offers the reader in their attempt to persuade them. A ethos appeal
is an appeal to a person’s character or authority. A pathos appeal is an appeal
to emotion. And a logos appeal is an appeal to fact or logic. An alternative way
to understand the distinction between eristics and dialectics is that, in eristics,
all three appeals are permissible, whereas in dialects, only logos appeals are
permissible.
References
Most of this document is the result of my own thinking. However, in preparing
this handout, I have also taken several examples directly from the following
two sources:
•
•
Kelley, David (1998). The Art of Reasoning. Norton.
Vaughn, Lewis (2016). The Power of Critical Thinking. Oxford UP.
I would also like to acknowledge, and express my thanks to, my friend, Ross
Preuss Greene, for helping me edit an earlier version of this document.
Bassford 2021u: Intro to Philosophical Reasoning
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Introduction to
Philosophy
Lecture 4, Epistemology:
Skepticism (Part 1)
Prof. Andrew D. Bassford
Austin Community College
Lecture 4 Readings
• [OPTIONAL] Celestine Bittle’s 1936 Reality and the Mind,
chapter 1. Bruce Publishing.
• [OPTIONAL] Rene Descartes’s 1640 Discourse on the
Method (Excerpt).
• Rene Descartes’s 1642 Meditations on First
Philosophy (First Excerpt).
• [OPTIONAL] Bertrand Russell’s “Appearance and
Reality.” From his 1912 Problems of Philosophy, chapter 1.
Epistemology
• Now that we’ve finished our discussion of logical and philosophical
dialectics, it is time to begin our study of the first major branch of topical
philosophy: epistemology.
• Definition: Epistemology is the philosophical science of knowledge. The
epistemologist is interested in whether, how, and to what extent we can
know anything at all.
• Questions that interest epistemologists include: What is knowledge? Do human
beings know anything? Supposing so, what are the different ways of knowing?
Does truth exist? If so, is it objective or subjective? And how, in general, ought we
go about forming beliefs about the world around us? … Is there even a world
around us?
Branches of
Philosophy
Logic
Metaphysics
Topical
Philosophy
Epistemology
Historical
Philosophy
Special
Branches
Axiology
Ancient
Ethics
Philosophy of
Mind
Medieval
Aesthetics
Philosophy of
Language
Modern
Philosophy of
Religion
Contemporary
Philosophy of
Science
Etc.
• In this unit of the course, we’ll investigate the subject of skepticism
and ask the specific question: On what basis, if any, can we claim
to know the existence and the nature of the external world
around us?
• But before getting underway, let’s start with the very basics and
ask the question: What, exactly, is knowledge?
What is Knowledge?
• Question: What is knowledge? What does it mean for someone to
know something?
• This is a difficult question. Without offering a definition yet, I think
we can note that there are at least three kinds of knowledge.
• First, there is propositional knowledge—i.e., knowledge of facts. When
someone has propositional knowledge, then they know that something is
the case. For example, if Jerry knows that George Washington was the first
president of the United States, then he has propositional knowledge-that
George Washington was the first president.
• Second, there is objectual knowledge—i.e., knowledge of particular
objects and phenomena in the world. When someone has objectual
knowledge, they simply know the object or have been acquainted with it
directly. So, if Jerry knows Bob, then Jerry has objectual knowledge-of Bob.
• And finally, there is procedural knowledge—i.e., knowledge of how to do
something. Procedural knowledge amounts to possessing a skill of how to
perform some task. So, if Jerry knows how to ride a bike, then Jerry has
procedural knowledge-how to ride a bike.
• Propositional knowledge, objectual knowledge, procedural
knowledge… In this unit, let’s bracket the latter two types of
“knowledge” and focus our attention on propositional
knowledge—know-that, rather than know-of or know-how.
• So, what is *propositional* knowledge?
• The most popular theory throughout the history of epistemology is
known as the JTB Theory of Knowledge. According to the JTB
Theory, propositional knowledge should be understood as justified,
true belief.
• That is, a person knows that something is the case (George
Washington was first president of the US) if and only if they believe
that this is true, their belief is in fact true, and they are justified in
believing it—i.e., they have good reason (evidence) in support of
their belief.
Knowledge as Justified, True Belief
• Why think that knowledge is ultimately
justified true belief?
• Well suppose that it’s raining in Austin,
TX. And now suppose Brandon lives in
San Francisco, CA. He has no beliefs
about the weather in Austin at all.
• Could Brandon possibly know-that it is
raining in Austin?
• JTB Theorists say No. And so, it appears
that having a belief about a certain
subject is necessary for knowledge
about it.
Brandon
• Now suppose, again, that it is raining
in Austin. Toni is indoors and there
are no windows around. He’s asked,
“Is it raining outside.” And Toni says
no—he believes falsely that it is
sunny outside.
• Could Toni possibly know-that it is not
raining in Austin?
• JTB Theorists say No. And so, it
appears that having a true belief
about a certain subject is necessary
for knowledge about it.
• You can’t know what ain’t so!
Toni
• Finally, suppose that it is raining outside.
Jason is likewise stuck indoors, and now
he is asked, “Is it raining outside?” Jason
has no idea, so he decides to flip a coin
to decide. Heads, it’s raining; tails, it isn’t.
The coin lands heads, and so he comes to
believe that it is raining outside.
• Could Jason possibly know-that it is raining
in Austin?
• JTB Theorists say No. He has no right to
claiming that he knows that it is raining
outside. And so, it would appear that it
matters how we form a belief whether it
should count as an instance of
knowledge. The belief must be justified.
Jason
• Question: What is (propositional) knowledge?
• JTB Theory: Knowledge is justified, true belief.
• Do you agree? Why or why not?
J
T
B
Skepticism
• The JTB Theory of Knowledge has come under some fire in the last 50
years or so, but we can bracket that dispute; it will serve our purposes
here. So let’s take the definition for granted and now ask the very big
question:
• Can we know anything?
• Question: What do you think? Explain.
• In answer to this question, there are two basic positions available.
• Dogmatism. According to the dogmatist, we can (and, in fact, do) have
knowledge of many facts of the world.
• Skepticism. According to the skeptic, we cannot (and, therefore, do not)
have knowledge of any facts of the world.
• Throughout the remainder of this lecture, we will be entering into a
conversation with a potential skeptic.
• Global vs. Local Skepticism
• Global skepticism is radical skepticism; according to the global skeptic, we have
no knowledge whatsoever. None of our beliefs whatsoever obtain the status of
justified, true belief.
• Local skepticism is less radical and has many different types. According to the
local skeptic, we have no knowledge about some particular subject matter. An
astrology skeptic, for example, claims only that astrology does not constitute
genuine human knowledge.
• Most people embrace local skepticism about certain subjects and local
dogmatism about others. Consider the claim that “Garlic is delicious.”
Can one know whether this claim is true or false? Some will say No:
claims about what is or is not delicious cannot constitute a knowledge
basis. This is a kind of local skepticism.
• Global skepticism—the position
that we cannot know anything
whatsoever—might seem like a
very radical position. It is. Why
might one think it is true?
• Question: What do you think? Why
might one endorse a position of
global skepticism? Is this a position
you endorse? Why or why not?
Rene Descartes
• Let’s meet one of the heroes of this
course: the French early modern
mathematician and philosopher,
Rene Descartes (17th century). (Don’t
put des cartes before the horse.)
• Descartes is undoubtedly one of the
greatest philosophers in western
history. He made major contributions
to epistemology, but also to
metaphysics, logic, physiology,
mathematics, and many other
disciplines.
• “Nothing seems more plain to the ordinary man, and more beyond
the possibility of any doubt, than the everyday facts of his
knowledge. He is utterly convinced of the truth and certainty of the
happenings in and around him. It never enters his mind to question
the validity of his convictions concerning the knowledge of his
experience.” (Bittle)
• I believe, for example, that:
1.
2.
3.
4.
George Washington was the first president of the United States.
I went to Western Michigan University.
There is a computer screen in front of me.
Rectangles are quadrilaterals.
• Why do I believe these things? It’s hard to say.
• “Facts of everyday experience, such as those mentioned above, could be
multiplied indefinitely. The ordinary man has a spontaneous and unshakable
conviction that they are genuinely true. No amount of argument could convince
him that his knowledge is not valid… Every moment of his life, from the cradle to
the gave, confirms his convictions that the world outside and around him is as he
experiences it to be and that his knowledge of it is a correct insight into its
reality.” (Bittle)
• Descartes’s legacy to philosophy: He refused to take his spontaneous
convictions at face value. Instead, he created a new method of doing
philosophy—the method of doubt, also called Cartesian skepticism. He
put all of his spontaneous convictions to the test…
Types of Evidence
• In a moment, we’ll look at
Descartes’s scandalous global- • Ordinary commonsense considers
skeptical doubts. Then, in the
each of these types of evidence as
next lectures, we’ll discuss how justification-conferring—i.e.,
he hoped to overcome them.
capable of justifying our
But in order to appreciate his
propositional knowledge.
remarks on this subject, let’s
first review some different types
1. Testimony
of evidence.
2. Memory
3. Perception
4. Reasoning
• These sources of evidence are often considered to be exhaustive of every possible kind of
justification. So, I believe many, many different things. Probably:
1.
My belief that GW was the first president is supposedly justified by testimony. This is something I’ve
been told by history teachers, who themselves were told by others.
2.
My belief that I went to WMU is supposedly justified by memory. I remember being there.
3.
My belief that there is a computer screen here is supposedly justified by perception. I just see the damn
thing!
4.
My belief that rectangles are quads is supposedly justified by reason. I know that rectangles have four
sides and that all four-sided figures are quadrilaterals; and so, I’ve inferred that rectangles are quads
too.
• Question 1: What is something you believe is true? What is your justification for thinking so? Is
it supported by testimony, memory, perception, reason, or something else?
• Question 2: Do I know these things (1-4), as I believe I do? Why or why not? Is the reason
offered in its support conclusive and immune from rational doubt?
The Cartesian Method
• Descartes set out to answer the question: Can we be certain of any of
our beliefs? That is, can we demonstrate that any of our beliefs about
the world must be true?
• “It is prudent never to trust completely [anything that has] deceived us even
once.”
• Descartes’s method to answer this question was to closely examine each
of his beliefs. He then posed the question: Is it possible that this belief is
false? And if the belief could be doubted with good reason, then he was
to treat it as if it were false, since no belief is justified if there is good
reason to doubt its truth. (Right?)
Reasons for Doubt
• The Cartesian Method. Treat any belief as false which can be doubted with good
reason.
• First Doubt. Is there good reason to doubt testimony as a source of evidence? Could
one ever be deceived by taking testimony as evidence for some belief?
• Yes! People can lie and so purposely deceive us. But people can also simply be mistaken and
give us false information intentionally. Therefore, any of our beliefs which are supposedly
supported by testimony should be taken as unjustified; no belief built on testimony is certain.
• This might not seem like a radical doubt, but consider that (almost) all of our knowledge
of history is, of necessity, built on testimony. Therefore, if testimony is not a legitimate
source of justification, all of our beliefs about history are unjustified and give us no
certain knowledge. Following the Cartesian method, we ought to be skeptical of all our
beliefs on this subject…
• Second Doubt. Is there good reason to doubt memory as a source of
evidence? Could one ever be deceived by taking memory as evidence for
some belief?
• Yes! Even though we often take our own memories as good evidence, memory is
notoriously unreliable…
• Memories can become distorted over time. New information gets added, information gets
lost, details get exaggerated or downplayed.
• Memories can be fabricated. Some people claim to genuinely remember events that have
never happened before and could not possibly have happened.
• This is a radical doubt. Consider that almost all of our knowledge of our
personal pasts is supposedly supported by memory. Therefore, if memory
is not a legitimate source of evidence, all of our beliefs about our own
personal history are unjustified and give us no certain knowledge.
Following the Cartesian method, we ought to be skeptical of all our beliefs
on this subject…
• Third Doubt. What about the evidence
of our senses? I currently see a
computer screen. Can I reasonably
doubt that perception is a legitimate
source of evidence? Can one ever be
deceived by their senses?
• Yes! Our senses can deceive us about
particular objects. But they can also deceive
us about the entire world at once…
• “Yet although the senses occasionally deceive us with respect to objects
which are very small or in the distance, there are many other beliefs about
which doubt is quite impossible, even though they are derived from the
senses—for example, that I am here, sitting by the fire, wearing a winter
dressing-gown, holding this piece of paper in my hands, and so on. Again,
how could it be denied that these hands or this whole body are mine?
Unless perhaps I were to liken myself to madmen, whose brains are so
damaged by the persistent vapors of melancholia that they firmly maintain
they are kings when they are paupers, or say they are dressed in purple
when they are naked, or that their heads are made of earthenware, or that
they are pumpkins, or made of glass. But such people are insane, and I
would be thought equally mad if I took anything from them as a model for
myself.” (Descartes, Meditation 1)
• The previous images show us that our senses can sometimes deceive us
about particular objects in experience. But the reasonable doubts run
even deeper…
• “A brilliant piece of reasoning! As if I were not a man who sleeps at night, and
regularly has all the same experiences while asleep as madmen do when awake—
indeed sometimes even more improbable ones. How often, asleep at night, am I
convinced of just such familiar events—that I am here in my dressing-gown,
sitting by the fire—when in fact I am lying undressed in bed! Yet at the moment
my eyes are certainly wide awake when I look at this piece of paper; I shake my
head and it is not asleep; as I stretch out and feel my hand I do so deliberately,
and I know what I am doing. All this would not happen with such distinctness to
someone asleep. Indeed! As if I did not remember other occasions when I have
been tricked by exactly similar thoughts while asleep! As I think about this more
carefully, I see plainly that there are never any sure signs by means of which being
awake can be distinguished from being asleep. The result is that I begin to feel
dazed, this very feeling only reinforces the notion that I may be asleep…”
(Descartes, Meditation 1)
• So, it appears that our senses can sometimes deceive us with
respect to particular objects from experience (illusions,
hallucinations, Gestalt objects) but also with respect to the entirety
of our experience of the world (dreams). So, at any particular
moment, we could be being fed false information from our senses.
And if what our senses are telling us are not true, then they grant
us no knowledge of the world at all.
• This is one of Descartes’s most radical doubts. All of our empirical sciences
(physics, astronomy, biology, chemistry, etc.) are based on the assumption
that perception can justify our beliefs. But, following the Cartesian method,
since the validity of perception can be reasonably doubted, it follows that we
ought to be skeptical of all our beliefs on this subject…
• “So a reasonable conclusion from this might be that physics, astronomy,
medicine, and all other disciplines which depend on the study of composite
things, are doubtful; while arithmetic, geometry and other subjects of this
kind, which deal only with the simplest and most general things, regardless
of whether they really exist in nature or not, contain something certain
and indubitable. For whether I am awake or asleep, two and three added
together are five, and a square has no more than four sides. It seems
impossible that such transparent truths should incur any suspicion of being
false.” (Descartes, Meditation 1)
• Fourth Doubt. We’ve now doubted the validity of all of our
empirical sciences. Can our rational sciences be doubted too? Can I
reasonably doubt that rationality itself is a legitimate source of
evidence? Can one ever be deceived by reason?
• Yes!
• “And yet firmly rooted in my mind is the long-standing opinion that there is an
omnipotent God who made me the kind of creature that I am. How do I know that
he has not brought it about that there is no earth, no sky, no extended thing, no
shape, no size, no place, while at the same time ensuring that all these things
appear to me to exist just as they do now? What is more, just as I consider that
others sometimes go astray in cases where they think they have the most perfect
knowledge, how do I know that God has not brought it about that I too go wrong
every time I add two and three or count the sides of a square, or in some even
simpler matter, if that is imaginable? But perhaps God would not have allowed me
to be deceived in this way, since he is said to be supremely good. But if it were
inconsistent with his goodness to have created me such that I am deceived all the
time, it would seem equally foreign to his goodness to allow me to be deceived
even occasionally; yet this last assertion cannot be made…” (Descartes)
• “Perhaps there may be some who would prefer to
deny the existence of so powerful a God rather than
believe that everything else is uncertain. Let us not
argue with them, but grant them that everything said
about God is a fiction… I will suppose therefore that
not God, who is supremely good and the source of
truth, but rather some malicious demon of the
utmost power and cunning has employed all his
energies in order to deceive me. I shall think that the
sky, the air, the earth, colors, shapes, sounds and all
external things are merely the delusions of dreams
which he has devised to ensnare my judgment. I shall
consider myself as not having hands or eyes, or flesh,
or blood or senses, but as falsely believing that I have
all these things…” (Descartes)
• So suppose that there is some omnipotent evil demon who can
convince you of anything whatsoever. And now suppose that 2+2 is
not 4 but actually 5. Could it be the case that you’re simply being
deceived anytime you add to thinking that 2+2=4? It seems rational
to you, but that’s the result of the demon’s deception…
• Do we have any good reason for denying the existence of such a
demon? It would seem not. So, then, we should admit that it is
possible. But if it is possible, then we cannot rule out the possibility
that this is precisely our epistemic situation. We cannot be certain
that rationality itself, as we understand is, is a trustworthy source
of evidence…
• The evil demon thought experiment would show something even more
radical, actually. If it’s possible that everything we believe is the result
of being tricked by an evil demon, whether we believe it on the basis of
testimony, memory, perception, or reason, then it would follow we
cannot be certain that any of our beliefs whatsoever are true. If the evil
demon exists, then we’d have good reason to be skeptical of them all.
• And so, it would appear that our rational sciences may be reasonable
doubted too. Our basic disciplines of logic, mathematics, and philosophy
are all based on pure reason.
• Following the Cartesian method, we ought to be skeptical of all our
beliefs on this subject… and every other subject whatsoever!
Sources of Evidence
Reasons for Doubt
Testimony
Lies, unintentional misinformation
Memory
Amplification, distortion, false memories
Perception
Illusions, hallucinations, dreams
Reason
The evil demon hypothesis
• The Cartesian Method: “It is prudent never to trust completely [anything that has]
deceived us even once… Reason now leads me to think that I should hold back my
assent from opinions which are not completely certain and indubitable just as
carefully as I do from those which are patently false. So, for the purpose of rejecting
all my opinions, it will be enough if I find in each of them at least some reason for
doubt.”
• Descartes’s Argument for Skepticism: Knowledge is justified, true belief. If any of
our beliefs are justified, then they are justified by either testimony, memory,
perception, or reason. But all four are open to rational doubt. Therefore, we cannot
be certain of any of our beliefs—global skepticism is the best position.
• Question: What do you think of Descartes’s Skeptical Argument?
Are you convinced by it? Are any of our beliefs justified? If so, how?
Or should we instead be global skeptics and suspend judgment on
every subject entirely?
• Summary of Lecture 4
• Epistemology is the philosophical science of knowledge—whether, how, and to
what extent can we ever know anything.
• The JTB Theory of Knowledge holds that knowledge is justified, true belief.
• Dogmatism is the belief that we can and do know some things. Skepticism is the
belief that we do not. Local skeptics hold that we do not have knowledge on
certain subjects. Global skeptics hold that we have no knowledge whatsoever.
• There are four basic sources of potential justification: testimony, memory,
perception, and reason.
• The Cartesian method of doubt is to treat every belief that can be reasonably
doubted as false and unable to justify anything. He offers us a skeptical argument
for doubting all four sources of potential justification. Therefore, his argument
leads us to accept global skepticism.
• Next time:
• In the next lecture, we will continue our discussion of skepticism.
Descartes, it should be noted, was not actually a skeptic, but we’ll wait
until part 3 of this series to address his response to his own skeptical
concerns. In the next lecture, we’ll look at one kind of response to
skepticism, a specific kind of dogmatism—empiricism. Empiricists
attempt to defend perception as a basis of justification. We’ll see how
this reply might work, and then we’ll consider problems with it.
Introduction to Philosophy
Lecture 3, Logic: Philosophical Reasoning (Part 2)
Prof. Andrew D. Bassford
Austin Community College
Readings for Lecture 3
• Andrew Bassford, “Introduction to
Philosophical Reasoning” In-Class
Handout.
• Michael Levin, “The Case for Torture.” This
will be the reading to accompany our
discussion board assignment this week.
Fallacies of Reasoning
• In this lecture, we are going to continue our study of logic, the
philosophical science of correct reasoning. Last time, we discussed
the basic components of argument analysis, and we introduced the
parts of a debate. This time, we’re going to continue our study by
looking at fallacies of reasoning.
• A logical fallacy is a faulty pattern of reasoning, whether within the
context of an argument or within a debate. There are many
different patterns that have been cataloged by logicians
throughout the millennia. Let’s survey some of the most important
and common ones.
1. The Subjectivist Fallacy
• So, what are some common ways in which reasoning goes wrong?
One of the most obviously bad forms of reasoning which is
nonetheless highly common (we’ve all done this!) is called the
subjectivist fallacy (i.e. motivated irrationality).
• Subjectivist Fallacy—using the fact that one believes or wants something
to be true as evidence of its truth, or to be false as evidence of its falsity.
• This is a bad form of reasoning because, just because one wants
something to be so, does not make it so.
Common Forms of the Subjectivist Fallacy
i.
Wishful Thinking—believing something because one wants it to be so or
not to be so.
• Joe is an alcoholic, but he wants to believe he is not; so, he denies any alcoholism.
ii. Self-Deception—believing something because one does not want the
opposite to be true. Often, self-deceivers sub-consciously know the
opposite to be true but will nonetheless consciously deny it.
• Maria’s son has been stealing from her purse almost every night once she goes to bed,
but she consciously denies this and holds instead that she has simply repeatedly
misplaced her money.
2. Begging the Question
• The subjectivist fallacy is a relatively innocent sort of fallacy, since most
people do it unintentionally. There are a few more fairly innocent
fallacies worth noting. Another common one is:
• Begging the Question (Circular Reasoning)—trying to support a position with an
argument in which that belief is already presumed to be true.
• This is a bad form of reasoning because the whole point of reasoning is to
show that some claim is true. But if one is already assuming it is true, then
there is no point in offering an argument in its support. When one begs the
question, they end up maintaining a self-sealing position.
Example of Begging the Question
• Alfred: God exists.
The Bible
says God
exists
God exists
• Bert: Why do you think so?
• A: Because it says so in the Bible.
• B: Why should we take the Bible’s word for it?
• A: Well, because the Bible is the Word of God.
• B: …
The Bible
is the
Word of
God
3. Equivocation
• Another type of (usually) benign fallacy:
• Equivocation—using a word in two different meanings in the premises
and/or the conclusion.
• This is a bad form of reasoning because when one changes the
meaning of a word, one in effect also changes the subject of the
conversation. This sort of fallacy creates a lot of confusion.
Example of Equivocation
• Alfred: I’m going to call the police on Charlene.
• Bert: Why??
• A: Because she plays baseball.
• B: … please explain.
• A: Well, she’s committing animal cruelty. She’s hitting the baseball with a bat, and
bats are living creatures! It’s so wrong!
• B: Lolz.
A more serious example:
• There used to be a very common argument in the philosophical
literature on the subject of abortion. It went like this:
1. It is morally wrong to kill innocent human beings.
2. Abortion is an act of killing an innocent human being.
3. Abortion is morally wrong.
• Question: Is this a good argument? Why or why not?
• Pojman’s evaluation
• “On the face of it, this looks like a good argument, and it is often used in
opposition to abortion. There may be good arguments opposed to abortion, but
this one, as it stands, is not one of them.
• Early on in the debate over abortion, philosophers like Michael Tooley and Mary
Anne Warren pointed out that the argument contains an equivocation over the
phrase human being. We use the term human being ambiguously, sometimes
meaning a biologic concept, the species Homo sapiens, and other times meaning
a psychological-moral concept, someone who has the characteristics that make
humans of special mor…