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Introduction to Logic and Argumentation

Argumentation

I. Aristotle (384 BC – 322 BC)

A. Aristotle hoped that mankind would embrace the logic of the syllogism for making arguments.

1. While he recognized the need for, and importance of, emotional appeals, he claimed that the affairs of mankind should be handled through logic

B. Made important contributions by systemizing deductive logic and wrote on physical subjects.

1. His philosophy had a long-lasting influence on the development of all Western philosophical theories.

C. Aristotle believed that logic was not a science but rather had to be treated before the study of every branch of knowledge.

1. Aristotle's name for logic was "analytics"

2. Aristotle proposed the now famous Aristotelian syllogism

a. Form of argument consisting of two premises and a conclusion.

b. His example is:

(i) Every Greek is a person.

(ii) Every person is mortal.

(iii) Every Greek is mortal.

D. However, Aristotle was not the first to suggest axiom systems.

1. Plato had made the bold suggestion that there might be a single axiom system to embrace all knowledge.

2. Aristotle went for the somewhat more possible suggestion of an axiom system for each science.

II. What is an argument?

To be able to think critically, it is very important that you can identify, construct, and evaluate arguments.

We shall be using the word "argument" in a way that is somewhat different from its ordinary meaning. In its ordinary usage, the word is often used to refer to a quarrel between two or more parties. But here we shall understand an argument as a piece of language. In particular, we shall take an argument to be a list of statements, one of which is the conclusion and the others are the premises or assumptions of the argument.

To give an argument is to provide a set of premises as reasons for accepting the conclusion. To give an argument is not necessarily to attack or criticize someone. Arguments can also be used to support other people's viewpoints.

As an example, suppose I want to convince you that you should be hardworking. I might give the following argument:

If you want to find a good job, you should be hardworking. You do want to find a good job. So you should be hardworking.

The first two sentences here are the premises of the argument, and the last sentence is the conclusion. To give this argument is to offer the premises as reasons for accepting the conclusion.

Dogmatic people tend to make assertions without giving reasons. When they are criticized they often fail to give arguments to defend their own opinions. To become a good critical thinker, you should develop the habit of giving good arguments to support your claims. Giving good arguments is one of the most important ways to convince other people that certain claims should be accepted.

III. How to look for arguments

How do we identify arguments in real life? There are no easy mechanical rules, and we usually have to rely on the context in order to determine which are the premises and the conclusions. But sometimes the job can be made easier by the presence of certain premise or conclusion indicators. For example, if a person makes a statement, and then adds "this is because ...", then it is quite likely that the first statement is presented as a conclusion, supported by the statements that come afterwards. Other words in English that might be used to indicate the premises to follow include :

• since

• firstly, secondly, ...

• for, as, after all,

• assuming that, in view of the fact that

• follows from, as shown / indicated by

• may be inferred / deduced / derived from

Of course whether such words are used to indicate premises or not depends on the context. For example, "since" has a very different function in a statement like "I have been here since noon", unlike "X is an even number since X is divisible by 4".

Conclusions, on the other hand, are often preceded by words like:

• therefore, so, it follows that

• hence, consequently

• suggests / proves / demonstrates that

• entails, implies

Here are some examples of passages that do not contain arguments.

When people sweat a lot they tend to drink more water. [Just a single statement, not enough to make an argument.]

Once upon a time there was a prince and a princess. They lived happily together and one day they decided to have a baby. But the baby grew up to be a nasty and cruel person and they regret it very much. [A chronological description of facts composed of statements but no premise or conclusion.]

Can you come to the meeting tomorrow? [A question that does not contain an argument.]

Do these passages contain arguments? If so, what are their conclusions?

1. Cutting the interest rate will have no effect on the stock market this time round as people have been expecting a rate cut all along. This factor has already been reflected in the market.

2. So it is raining heavily and this building might collapse. But I don't really care.

3. Virgin would then dominate the rail system. Is that something the government should worry about? Not necessarily. The industry is regulated, and one powerful company might at least offer a more coherent schedule of services than the present arrangement has produced. The reason the industry was broken up into more than 100 companies at privatisation was not operational, but political: the Conservative government thought it would thus be harder to renationalise.  The Economist 16.12.2000

4. Bill will pay the ransom. After all, he loves his wife and children and would do everything to save them.

5. All of Russia’s problems of human rights and democracy come back to three things: the legislature, the executive and the judiciary. None works as well as it should. Parliament passes laws in a hurry, and has neither the ability nor the will to call high officials to account. State officials abuse human rights (either on their own, or on orders from on high) and work with remarkable slowness and disorganisation. The courts almost completely fail in their role as the ultimate safeguard of freedom and order.   The Economist 25.11.2000 \

6. Most mornings, Park Chang Woo arrives at a train station in central Seoul, South Korea's capital. But he is not commuter. He is unemployed and goes there to kill time. Around him, dozens of jobless people pass their days drinking soju, a local version of vodka. For the moment, middle-aged Mr Park would rather read a newspaper. He used to be a brick layer for a small construction company in Pusan, a southern port city. But three years ago the country's financial crisis cost him that job, so he came to Seoul, leaving his wife and two children behind. Still looking for work, he has little hope of going home any time soon.   The Economist 25 .11.2000

7. For a long time, astronomers suspected that Europa, one of Jupiter's many moons, might harbour a watery ocean beneath its ice-covered surface. They were right. Now the technique used earlier this year to demonstrate the existence of the Europan ocean has been employed to detect an ocean on another Jovian satellite, Ganymede, according to work announced at the recent American Geo-physical Union meeting in San Francisco.   The Economist 16.12.2000    \

8. There are no hard numbers, but the evidence from Asia’s expatriate community is unequivocal. Three years after its handover from Britain to China, Hong Kong is unlearning English. The city's gweilos (Cantonese for “ghost men”) must go to ever greater lengths to catch the oldest taxi driver available to maximize their chances of comprehension. Hotel managers are complaining that they can no longer find enough English- speakers to act as receptionists. Departing tourists, polled at the airport, voice growing frustration at not being understood. The Economist 20.1.2001

MODEL 1: THE SYLLOGISM

IV. Presenting arguments in the syllogistic format

You will recognize the syllogism as the old "fluffy is a mammal" argument. It goes like this:

All cats are mammals.

Fluffy is a cat.

Therefore, fluffy is a mammal.

When it comes to the analysis and evaluation of an argument, it is often useful to label the premises and the conclusion, and display them on separate lines with the conclusion at the bottom:

(Major Premise) If you want to find a good job, you should be hardworking.

(Minor Premise ) You do want to find a good job.

(Conclusion) So you should be hardworking.

Let us call this style of presenting an argument a presentation as a syllogism.

Major premise: A general statement.

Minor premise: A specific statement.

Conclusion: based on the two premises.

Here we rewrite two more arguments using the standard format:

We should not inflict unnecessary pain on cows and pigs. After all, we should not inflict unnecessary pain on any animal with consciousness, and cows and pigs are animals with consciousness.

(Major Premise) We should not inflict unnecessary pain on any animal with consciousness.

(Minor Premise) Cows and pigs are animals with consciousness.

(Conclusion) We should not inflict unnecessary pain on cows and pigs.

If this liquid is acidic, the litmus paper would have turned red. But it hasn't, so the liquid is not acidic.

(Major Premise) If the liquid is acidic, the litmus paper would have turned red.

(Minor Premise) The litmus paper has not turned red.

(Conclusion) The liquid is not acidic.

In presenting an argument in the syllogistic format, the premises and the conclusion are clearly identified. Sometimes we also rewrite some of the sentences to make their meaning clearer, as in the second premise of the second example. Notice also that a conclusion need not always come at the end of a passage containing an argument, as in the first example. In fact, sometimes the conclusion of an argument might not be explicitly written out. For example it might be expressed by a rhetorical question:

How can you believe that corruption is acceptable? It is neither fair nor legal!

In presenting an argument in the standard format, we have to rewrite the argument more explicitly as follows:

(Premise) Corruption is not fair and it is not legal.

(Conclusion) Corruption is not acceptable.

If you want to improve your reading and comprehension skills, you should practise reconstructing the arguments that you come across by rewriting them carefully in the syllogistic format.

Rewrite these arguments in the syllogistic format.

1. He is either in Hong Kong or Macau. John says that he is not in Hong Kong. So he must be in Macau.

2. If the Government wants to build an incinerator here they should compensate those who live in the area. Incinerators are known to cause health problems to people living nearby. These people did not choose to live there in the first place.

MODEL 2: THE TOULMIN MODEL OF ARGUMENT

Stephen Toulmin, originally a British logician, is now a professor at USC. He became frustrated with the inability of formal logic to explain everyday arguments, which prompted him to develop his own model of practical reasoning.

V. The first triad of his model consists of three basic elements:

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A. A claim is the point an arguer is trying to make. The claim is the proposition or assertion an arguer wants another to accept.

1. The claim answers the question, "So what is your point?"

a. (ex) "You should send a birthday card to Mimi, because she sent you one on your birthday."

b. (ex)"I drove last time, so this time it is your turn to drive."

2. There are three basic types of claims:

a. Fact: claims which focus on empirically verifiable phenomena

b. Judgment/value: claims involving opinions, attitudes, and subjective evaluations of things

c. Policy: claims advocating courses of action that should be undertaken

B. Grounds refers to the proof or evidence an arguer offers.  

1. Grounds answers the questions, "What is your proof?" or "How come?" or "Why?"

a. Grounds can consist of statistics, quotations, reports, findings, physical evidence, or various forms of reasoning.

i. (ex) "It looks like rain. The barometer is falling."

ii. (ex): "The other Howard Johnson's restaurants I've been in had clean restrooms, so I'll bet this one has clean restrooms too."

2. Grounds can be based on:

a. evidence: facts, statistics, reports, or physical proof,

b. source credibility: authorities, experts, celebrity endorsers, a close friend, or someone's say-so

c. analysis and reasoning: reasons may be offered as proof

C. The warrant is the inferential leap that connects the claim with the grounds.

1. The warrant is typically implicit (unstated) and requires the listener to recognize the underlying reasoning that makes sense of the claim in light of the grounds.

2. The warrant performs a "linking" function by establishing a mental connection between the grounds and the claim

a. (ex) "Muffin is running a temperature. I'll bet she has an infection."

warrant: sign reasoning; a fever is a reliable sign of an infection

b. (ex) "That dog is probably friendly. It is a Golden Retriever."

warrant: generalization; most or all Golden Retrievers are friendly

3. Warrants can be based on:

a. ethos: source credibility, authority

b. logos: reason-giving, induction, deduction

c. pathos: emotional or motivational appeals

d. shared values: free speech, right to know, fairness, etc.

* note: these categories aren't mutually exclusive, there is considerable overlap among the three

VI. The second triad of the Toulmin model involves three addditional elements:

A. Backing provides additional justification for the warrant.

1. Backing usually consists of evidence to support the type of reasoning employed by the warrant.

B. The qualifier states the degree of force or probability to be attached to the claim.

1. The qualifier states how sure the arguer is about his/her claim

C. The rebuttal acknowledges exceptions or limitations to the argument.

1. The rebuttal admits to those circumstances or situations where the argument would not hold.

if we strip Toulmin's model down to its more classical form, called a syllogism.A syllogism strips the inner argument out of context and reduces it to

            1. A major premise (served by the Warrant)

            2. A minor premise (served by the Evidence) and

            3. A conclusion (served by the Claim)

VII. The Enthymeme (AKA – “TRUNCATED SYLLOGISM”)

The enthymeme is the rhetorical syllogism in which part of the logical sequence is left unstated (In other words, it is the linkage of a specific statement with the conclusion without listing the key premise).

For example:

Some politicians are corrupt.

Therefore, Senator Jones could be corrupt.

Ex1: - All humans are mortal. (major premise)

       - Michael is human. (minor premise)

       - Michael is mortal. (conclusion)

The syllogism above would be rendered an enthymeme simply by maintaining that "Michael is mortal because he's human" (leaving out the major premise). Or put differently, "Since all humans are mortal, Michael is therefore mortal" (leaving out the minor premise). Statements may be strategically excluded in an enthymeme because they are too obvious or because revealing them might damage the force of the argument. Yet another reason to exclude a premise or conclusion is to let the audience infer it. The idea here is that audiences who have to draw out premises or conclusions for themselves are more likely to be persuaded by the overall argument.

Ex2: - Those who study rhetoric speak eloquently. (major premise)

       - Susan studies rhetoric. (minor premise)

       - Susan speaks eloquently. (conclusion)

The enthymeme here might do well to exclude the conclusion and let the audience infer it if the goal of the argument were to convince the audience that Susan speaks eloquently.

Exercises for Part A

For each of the discussions or paragraphs below, identify 1) the parts of the argument using Toulmin's model and 2) the syllogism (or enthymeme) embedded in it.

1. ___

Sam: Al Capone was a thief and murderer.

Sharon: The only thing he was ever convicted of was income tax evasion.

Sam: Yes, but we know from confessions by his associates that he ordered such crimes.

2. In an atmosphere of unbridled hope for the future and a public committed to the belief in progress, college founding committees would not restrain their ambitions within considerations of finance and risk. So it was that hundreds of ill-fated colleges were established in antebellum 19th Century America.

3. ___

Sam: Early American colleges were violent places. Just consider the Harvard food riots.

Sharon: Yes, particularly since such things didn't make the newspapers.

Sam: What can you expect when the students were not permitted to have electives?

4. The German model of the university, de-emphasizing teaching and exaggerating scholarship, would eventually generate a form of highly articulated professionalism among the faculty that could not be cost-effective in promoting teaching excellence as it would be conceived of in the later 20th Century. Better a professor neglect teaching than publishing. It is the kiss of death at many universities in the United States for an untenured professor to receive a MacArthur Award for Excellence in Teaching.

5. ___

Sam: Making concessions to parents because they threaten a law suit is a bad practice. Look at how school budgets have expanded for often useless accommodations.

Sharon: But what about the risk of incurring higher losses by fighting such suits?

Sam: Everything has some aspect of risk. Why assume the worst possible outcome without reckoning in its probability of occurrence?

 

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