PREMISE(S)

Claimed (andgenerally acceptedas ‘fact’) evidence

CONCLUSION

What is claimedto follow fromthe premises

An Argument

REMINDER – For it to be an ARGUMENT, 1) at least one statement must claim to present evidence 2) there must be a claim that the evidence implies something 3) it can NOT be just a contradiction (recall the movie )

2.2 Recognizing Arguments2.2 Recognizing Arguments

Premise – A statement used in an argument which provides the supposed “evidence” needed in order to support some other

statement which we are to supposed believe follows from the premise (or premises)

Conclusion – The statement in an argument that the other “factual” statement (or statements) claim to support and

provide evidence

We generally disclose the fact that we are arguing by using words and phrases like ‘thus’, ‘since’, ‘hence’, ‘therefore’, ‘we see that,’ and so forth. These expressions are called illatives, and their purpose is to show that someone is making an argument. Some illatives (e.g., ‘thus’, ‘therefore’, and ‘it follows’) mark conclusions; others (e.g., ‘since’, ‘as’, and ‘for the reason that’) mark premises.

.

Premise indicator words:since (not temporal) as indicated bybecause* forin that may be inferred fromas given thatseeing that for the reason thatinasmuch as owing to

Conclusion indicator words:therefore whereforeaccordingly we may concludeentails that hencethus* consequentlywe may infer it must be thatfor this reason it follows thatimplies that as a result

*Note: "Because" and "thus" can be used in both explanations and arguments.

.While illatives (indicator words) often indicate that an

author is reasoning, they are not conclusive. Also, in many arguments, there are no indicator words; the general context may disclose that the author is making an argument. Here is an example:

In this passage, the first sentence expresses the conclusion, and premises follow, but there are no illatives (indicator words).

.Sometimes it is just the meaning of the passage or its setting (context) that indicates the presence of an argument.

Whether or not to smoke is a conscious decision made in the light of an abundance of information on the lethal effects of tobacco. Surely those who choose unwisely should bear the cost of any resulting ill health.

No illatives (premise-indicators or conclusion-indicators) are used here, yet the argument is unmistakable.

.That there was a racial imbalance in student attendance

was not tantamount to a showing that the school district was in noncompliance with its duties under the law. Racial balance is not to be achieved for its own sake. It is to be pursued when racial imbalance has been caused by a constitutional violation. Once the racial imbalance due to the de jure violation has been remedied, the school district is under no duty to remedy imbalance that is caused by demographic factors.

The first sentence of this passage presents the conclusion of the argument, and the sentences that follow after it offer the reasons (the evidence) for what has gone on before the current imbalance.

.Most arguments can be made plain by their contexts. If I called from the office and said, “I’ll be bringing two

lobsters home for dinner,” you probably would not set more places at the table but would instead make sure that there was a large pot of boiling water on the stove when I got there.

You might, however, have to think about it a little longer if I just walked in from the barn and announced,

“The pig is ready to eat.”Do you know if…. The pig is hungry or cooked?

.Context can tell you a lot about arguments.

Also worth noting is that many arguments contain additional material that is neither part of the conclusion nor part of the premises.

Some of it is useless, but occasionally it can serve as background material that can help the reader (or listener) better understand what the argument is about.

If the criminal law forbids suicide, that is not an argument valid in the Church, and besides, the prohibition is ridiculous. For what penalty can frighten a person who is not afraid of death?

.All statements in an argument are supposed to be in

declarative form, but the premise in the previous argument was obviously a rhetorical question.

For what penalty can frighten a person who is not afraid of death?

When a person asked a rhetorical question, she typically assumes that everyone will answer it with some inescapable answer. The answer to the “what penalty” question is presumably “none.”

Thus, the rhetorical question could be re-written in a declarative form as “There is no penalty that can frighten a person more than death itself.”

.Using rhetorical questions as either premises or

conclusions in an argument is risky (and should be avoided), because the answer is not always “obvious” to everyone.

If there is no one who desires to be miserable, there is no one, Meno, who desires evil; for what is misery but the desire and possession of evil?

When Socrates asked this question, was he correct in assuming that misery is the desire and possession of evil? The answer to the question is not obvious.

Because the answer is not always obvious, many people (especially those in politics) like rhetorical questions for that very reason!!!

.Declarative

statements can be said to be either true or false, but rhetorical questions have no truth value and so, for that very reason, are used to avoid responsibility for a forth-right assertion of a dubious claim. A dubious claim

.A former Secretary of Labor, opposing a later nominee for

the same post, asked in an op-ed column in the New York Times: “If she doesn’t believe the person working for her was an employee, how vigorously will she protect employees in general?”

Did the author assert that she, the nominee, would not protect employees?

No, he didn’t ‘say’ that.He might have implied it, but since he never actually ‘said’

it, we cannot know whether it is true or false that he even believes that the nominee would not protect employees. So his question becomes mere meaningless political jargon.

.If a right to euthanasia is grounded in self determination, it

cannot reasonably be limited to the terminally ill. If people have a right to die, why must they wait until they are actually dying before they are able to exercise that right?

The implicit answer (there is no good reason, and therefore the claim that “people need not wait until they are actually dying before the are permitted to exercise that right”) is assumed to be inescapable.

.Arguments sometimes conclude with an imperative

(command) statement. Reasons to perform a given act are set forth, and we are then directed to act in that way.

In Hamlet, Polonius gives the famous argument in guiding his son, Laertes:

.Strictly speaking a command (an imperative), like a question, cannot be a statement in an argument because it has no truth value.

But in many situations, it is useful to regard a command (when it’s the conclusion of an argument) as no different from a statement (or proposition).

In the previous examples, the conclusions could be written as “You ought to be neither a lender nor a borrower” and “Getting wisdom is what you should do.”

Most people will agree that assertions of this kind can be true or false.

.We seek to grasp the substance of what is being asserted,

to understand what claims are serving to support what inferences, whatever their external forms.

Some needed reformulations are merely grammatical.A proposition that functions as a premise may take the

form of a phrase, rather than a declarative sentence.This is well illustrated in the following passage discussing

the possibility of extraterrestrial life.

Is there life beyond earth? The jury is still out. But with Is there life beyond earth? The jury is still out. But with (P(P11) planets aplenty; with (P) planets aplenty; with (P22) creatures that can live ) creatures that can live without the energy of a nearby star; with (Pwithout the energy of a nearby star; with (P33) abundant) abundantresources of cosmic hydrogen and oxygen to make water;resources of cosmic hydrogen and oxygen to make water;with (Pwith (P44) several natural ways for planets to generate) several natural ways for planets to generateinternal heat; with (Pinternal heat; with (P55) the possibility that life could originate) the possibility that life could originatein undersea volcanoes and propagate varieties hardy in undersea volcanoes and propagate varieties hardy enough to spread their seeds to other worlds; and with enough to spread their seeds to other worlds; and with (P6) rocky meteorites that could serve as vehicles for (P6) rocky meteorites that could serve as vehicles for interplanetary exchange; (C:) the idea that life has evolved interplanetary exchange; (C:) the idea that life has evolved elsewhere in the universe seems less daunting than it did elsewhere in the universe seems less daunting than it did just a few years ago.just a few years ago.

There are six distinct premises (although not complete statements), each of which calls attention to recently discovered “facts” or at least “possibilities.”Each could be rephrased as a declarative statement: “There are plenty of planets.” “Many creatures can live without the energy of a nearby star.” And so forth.

Unstated Statements: Enthymemes

Arguments become even more complicated when one or more of their constituent propositions is not stated but assumed to be understood.

This, by the way, is how we talk in “real life.”A friend tells you, “It’s really sad that Mary’s father had a heart attack. He should have gone to see the doctor more regularly.”What premise is assumed but not stated?

.

The argument:People who do not see the doctor regularly are more apt

to have heart attacks. (missing)Mary’s father did not regularly see the doctor.Therefore, Mary’s father was apt to (and did) have a

heart attack.

.He would not take the crown;Therefore, ‘tis certain he was not ambitious.

(William Shakespeare, Julius Caesar, Act 3, scene 2)

The unstated (but plausible) statement is “One who would not accept the crown must not have been ambitious.”

The effectiveness of an enthymeme depends upon whether or not the hearer recognizes the missing and can agree that missing statement is true.

Sometimes the arguer presupposes that the hearer will know the missing statement is false: “If slavery is not wrong, nothing is wrong.”

.“If slavery is not wrong, nothing is wrong.”It is of course wildly false to say that nothing is wrong, and

from that it follows that it is equally false to say that slavery is wrong.

This was a clever argument used by Abraham Lincoln, because everyone could think of something that he or she regarded as “wrong.”

But what if the hearer thinks the missing statement is false?

Then the claim (conclusion) of the argument is very much in dispute, and if in dispute, the conclusion does not necessarily follow – thus, the argument is invalid.

2.3 Arguments & Explanations2.3 Arguments & Explanations

Compare these two passages:(1) Lay up for yourselves treasures in heaven, where

neither moth nor rust consumes and where theives do not break in and steal. For where your treasure is, there will your heart be also. -- Matt. 7:19

(2) Therefore the name of the tower is Babel; because the Lord did there confound the language of the earth. -- Gen. 11:19

The first passage is an argument. How do you know that?The second passage has indicator words (‘therefore’ &

‘because’), but is it an argument?

.The second passage explains why the tower was called

Babel, because it was the place where humankind, formerly speaking one language, became confounded by many languages.

The passage assumes that the reader knows the “fact” of the name, and so the intention is to explain why (i.e., the “because”) the name was given to the place.

.Unlike arguments, explanations don’t prove anythingThe “known thing” is a matter of “fact,” and the explanation

is intended to show “why” the fact is true

EXPLANANDUM – the statement that describes an event or phenomenon (such as the name of the tower); this is the “accepted fact”

EXPLANANS – the statement or group of statements that purport to do the explaining (such as “why” the tower is called “Babel”); this is the “why”

Note: in Latin, “um” mean singular (one fact), and the “s” means plural (the statements doing the explaining); this might be helpful as a memory trick

ARGUMENT EXPLANATION

Premises

accepted

facts

Claim to

prove

|

|

|

|

Conclusion

THAT

Explanans

accepted

fact

Claim to

shed

light on

|

|

|

|

ExplanandumWHY

.The Challenger exploded after lift-off (explanandum)because of a failed O-ring. (explanans)

Many explanations can be re-expressed as arguments.Explanation: The sky appears blue (explanandum) Because light rays from the sun are scattered by …

moisture particles in the air. (explanans)Argument: Light rays from the sun are scattered……. (premise) Therefore, the sky appears blue. (conclusion)

Warning: “Because” can be in both arguments & explanations.

.To distinguish explanations from arguments, identify the statement

that is either the explanandum or the conclusion (usually this is the statement that precedes the word ‘‘because’’). If this statement describes an accepted matter of fact, and if the remaining statements purport to shed light on this statement, then the passage is an explanation.

This method works for practically all passages that are either explanations or arguments (but not both).

Perhaps the greatest problem confronting the effort to distinguish explanations from arguments lies in determining whether something is an accepted matter of fact. Obviously what is accepted by one person may not be accepted by another. Thus, the effort often involves determining which person or group of people the passage is directed to—the intended audience. Sometimes the source of the passage (textbook, newspaper, technical journal, etc.) will decide the issue.

If in doubt, ask, “Would this be an accepted that fact that people would ordinarily know?” If you’re still not sure, treat it like an argument. Am I convinced by the premises to believe this “fact”?

.Exercise: Determine which of the following passages are

arguments and which are explanations. 1. Women tend to have higher pitched voices than men

because they have shorter vocal chords. Shorter vocal chords vibrate at a higher frequency than longer ones.

2. Freedom of the press is the most important of our constitutionally guaranteed freedoms. Without it, our other freedoms would be immediately threatened. Furthermore, it provides the fulcrum for the advancement of new freedoms.

3. Water is a good solvent for many different substances, and it picks them up as it moves through the environment. Thus, rain water flowing over and under the ground dissolves minerals such as limestone.

.4. If the earth’s magnetic field disappears, then the Van

Allen radiation belt will be destroyed. If the Van Allen radiation belt is destroyed, then intense cosmic rays will bombard the earth. Therefore, if the earth’s magnetic field disappears, then intense cosmic rays will bombard the earth.

5. Five college students who were accused of sneaking into the Cincinnati Zoo and trying to ride the camels pleaded no contest to criminal trespass yesterday. The students scaled a fence to get into the zoo and then climbed another fence to get into the camel pit before security officials caught them, zoo officials said.

6. Mortality rates for women undergoing early abortions, where the procedure is legal, appear to be as low as or lower than the rates for normal childbirth. Consequently, any interest of the state in protecting the woman from an inherently hazardous procedure, except when it would be equally dangerous for her to forgo it, has largely disappeared.

8.7 Disjunctive & Hypothetical Syllogisms

A syllogism is a short argument that contains two premises and a conclusion.

A disjunctive (or alternative) syllogism contains a disjunctive statement as one of its premises.

Consider this disjunctive syllogism:Either she was driven by stupidity or by arrogance.She was not driven by stupidity.Thus, she was driven by arrogance.

.The two components of a disjunctive (“or”) statement are

called the “disjuncts.” So the two disjuncts in the previous example are:

Either she was driven by stupidity or she was driven by arrogance

Because the sentence has a compound predicate and a single subject, the “she was” is part of both disjuncts

A disjunctive statement in Logic (unlike in real life) does not assume one disjunct is true and the other one is false; it merely assumes one is true; in fact, both may be true (which is why Logic has an “inclusive ‘or’ ”

.In a disjunctive syllogism, one premise is a disjuctive

statement and another premise denies the truth of one of the disjuncts in the disjunctive statement.

The conclusion is the remaining disjunct.

Example:

You can eat either the orange or the apple. or

You can’t eat the orange. not

Therefore, you can eat the apple.

In Logic, the tilde (~) means “not” or “it’s false that,” and the wedge (\/) means “or.”

.

Anything can go inside the shapes. The Circle could stand for “no fish in the sea” and the Square could stand for “no fish in the air.”

Thus the disjunctive syllogism would be:P1: Either there are no fish in the sea or no fish in the air.P2: It’s false that there are no fish in the sea.C: Therefore, there are no fish in the air.

This pattern is the general “rule” for a disjunctive syllogism. It says,

P1: Either Circle or SquareP2: Not Circle C: Therefore, Square.

No fish inthe air

No fish inthe air

No fish inthe sea \/

~______________No fish inthe sea

Read as:It is false that there areare no fish in the sea =

fish are in the sea

Either there are

Smith is not inParis

Smith isnot in New

York\/

~______________

Read as:It is false that Smith is

not in New York =Smith is in New York

Smith isnot in New

York

Smith is not inParis

Either

Since Smith IS inNew York, he cannot

be in Paris

.The second type of most common syllogism is one in

which one or more of the three statements is a conditional statement.

The one you probably know from math is the one called a Hypothetical Syllogism in which all the statements (both premises and the conclusion) are conditional statements.

In a syllogism, the order of the premises does not matter.

If “X” is a man, then “X” will die. B -> CIf Socrates is an “X,” then Socrates is a man. A -> BTherefore, if Socrates is an “X,” then Socrates will die. A -> C

A B

B .C

.

A .C

MP

MT

AC – fallacy

fallacy – DA

Together, AC and DA have over the yearsacquired the name of MODUS MORONS –in other words, avoid these two fallacies!!!

VALID

VALID

.I go to Publix I will spend money

I go to Publix

I will spend money

Modus Ponens (MP)

I go to Publix

I go to Publix

I will spend money

I will spend money

Modus Tollens (MT)

.“Modus Morons” versions:Affirming the Consequent (AC):

If I go to Publix, then I will spend money.I will spend money.Therefore, I will go to Publix.

The fallacy: I can spend money at LOTS of places besides Publix!!!

Denying the Antecedent (DA):If I go to Publix, then I will spend money.I will not go to Publix.Therefore, I will not spend money.

The fallacy: Similar to that above; even if I do not go to Publix, that is no guarantee that I will not spend money!

.Exercises. Pages 293-297