The conclusion and/or one or more premises are unstated

In document LearningExpress s EXAM SUCCESS GMAT. In Only 4 Steps! (Page 101-106)

What to Expect on the GMAT

2. The conclusion and/or one or more premises are unstated

The conclusion of one argument serves as the premise for another. Like essays, arguments are often richly layered. For example, look at the following argument:

You should present our position to the board. The board members trust you because they have known you for years, and you know our position better than anyone.

The claim the board members trust you actually serves as both the premise for the conclusion you should present to the board and the conclusion for a second argument: The board members trust you (conclusion) because they have known you for years (premise). This might be represented as follows:

conclusion ➝ premise/(becomes) conclusion ➝ premise

Sometimes this argument construction will be easy to detect; other times quickly mapping out the argu-ment can help. To do this, put brackets [] around each claim (remember that each sentence can have more than one claim). Then determine which of those claims is the main claim—the overall point of the argument.

Just as an essay may have many main ideas (a main idea for each paragraph), it also has an overall main idea.

Similarly, an argument can have many different conclusions that are part of a larger argument, and the argu-ment should have one main claim (the overall conclusion). Label this main claim C1 (conclusion 1). Then look carefully at the premises. Do they directly support C1? If so, label them P1 (premises that support C1).

But if they do not directly support C1, then you might have a secondary (or tertiary, etc.) conclusion. For example, they have known you for years doesn’t directly support the claim you should present our position to the board. Thus, you need to find the claim it does directly support (the board members trust you) and label that claim C2. Thus, the claim the board members trust you is labeled both P1 and C2, and they have known you for years is labeled P2 (premise supporting C2). Meanwhile, you know our position better than anyone directly supports C1, so it is labeled P1:

C1 P1/C2

[You should present our position to the board.] [The board members trust you] because

P2 P1

[they have known you for years] and [you know our position better than anyone.]

Here is another example:

P3

[With more and more classes being offered online, more and more students will soon earn their degrees P3

in virtual universities.] [Already, students in California are graduating from schools in New York without ever P2/C3

leaving their state.] Because [online courses offer flexibility without geographic boundaries],

P1/C2 C1

[virtual degrees will be in ever greater demand], and [colleges and universities should invest the bulk of their resources in developing online degree programs.]

In this argument, the final claim is the overall conclusion, the main claim of the argument.

Identifying the main claim (which we will refer to simply as the conclusion for the rest of this section) is a critical skill on the GMAT exam. You must be able to identify the conclusion to effectively evaluate an argument, and you need to be able to see when the conclusion is in fact missing from an argument. This is the second complication:

The premise and/or conclusion of an argument is unstated. These arguments are common both in real life and on the GMAT exam. The problem with an argument that contains unstated premises and conclusions is that it leaves room for the premise or conclusion to be misunderstood. For example,

You should turn her in for cheating. She violated the honor code.

This argument has an unstated premise—a key idea that links the conclusion and premise together. In order for this argument to be clear and strong, you need to know the unstated assumption that makes this argument possible:

People who violate the honor code should be turned in.

This could be stated in a slightly different way, but the assumption behind this argument is now clear.

This is crucial because unless you understand all of the premises upon which an argument is based, you can-not effectively evaluate that argument and determine whether or can-not it is valid.

Here is another example of an argument with an unstated premise:

We should offer online classes because other schools are now offering online classes.

At first glance, this might seem like a simple case of poor logic, an “everyone else is doing it” approach.

But if you recognize the unstated assumption, then this is a much stronger argument:

We need to do what other schools are doing to stay competitive.

C R I T I C A L R E A S O N I N G

Finding an Unstated Premise

When you are presented with an argument that has an unstated premise, you need to determine what claim would link the existing premise and conclusion together. What must be true (assumed) in order for the con-clusion to be true? This missing premise is a necessary transition or bridge between the premise and conclusion, one that probably makes the conclusion true. For example, look at the following argument:

P C

[Ellen plagiarized.] [She should be punished.]

An argument that jumps from premise to conclusion like this is called a non sequitur (jumping to con-clusions). This can be corrected by stating the premise that links the conclusion and premise:

P P C

[Ellen plagiarized.] [Plagiarism is wrong.] [Therefore, she should be punished.]

Here is another example. Notice how the unstated premise links the premise to the conclusion in the second version:

I promised to clean the garage on Saturday. I better clean the garage on Saturday. (non sequitur)

I promised to clean the garage on Saturday. People should keep their promises. I better clean the garage on Saturday. (logical, complete argument)

Not every argument with an unstated premise is a non sequitur, but you should follow essentially the same process to determine and evaluate unstated assumptions. Take another look at question 8 from the pretest, for example. This question asks you to determine which assumption the conclusion is not based upon:

8. Morning Glory, the coffee shop on the corner, has lost nearly 50% of its business because a national retail coffee chain opened up a store down the street. Instead of closing up shop, the owner of Morn-ing Glory plans to draw in customers by offerMorn-ing coffee, tea, and pastries at much lower prices than the national coffee chain.

The owner’s plan of action is based on all of the following assumptions EXCEPT a. some customers will choose the coffee shop that offers the lowest price.

b. the quality of Morning Glory’s coffee is comparable to that of the national coffee chain.

c. Morning Glory can afford to cut its profit margin in order to lower prices.

d. Morning Glory’s customers are very loyal.

e. the national coffee chain will not lower its prices in order to compete with Morning Glory.

The first step to tackling this question is to clearly identify the core argument. This plan of action could be reworded as follows:

P C

Now, this argument has several unstated assumptions. To answer the question, you need to identify which one is not a logical connection between the premise and the conclusion. You can simply insert each choice between the premise and conclusion to see if it forms a logical link:

P P

[Its prices will be lower than the national coffee chain’s] and [ ] so C

[Morning Glory will stay in business].

Broken down in this manner, it should be easy to see that all of the assumptions except d form a logi-cal link between premise and conclusion. If customers are loyal, they will continue to patronize Morning Glory, whether or not their prices are lower. This is the only assumption that does not fit the argument.

Determining an Unstated Conclusion

Determining the unstated conclusion of an argument is like finding an implied main idea. In a reading pas-sage, you would ask the following questions: What overall impression do the examples and ideas in the text add up to? What idea or concept do the ideas from the text support? Similarly, in critical reasoning, you must ask the following questions:

What do these premises add up to?

What idea or claim does this evidence amount to?

If these premises are true, what else then is also likely to be true?

For example, look at the following passage:

Rajita paid \$35 for her scarf at Hanson’s on sale. The same scarf is \$20 (regular price) at Lambert’s and only \$18 (regular price) at Sam’s.

Which one of the following conclusions can be logically drawn from the passage?

a. Rajita does not know where to shop.

b. There is no Sam’s or Lambert’s in Rajita’s area.

c. You will probably pay more for most items at Hanson’s than at Lambert’s or Sam’s.

d. Sam’s sale prices are always the best.

e. Rajita bought the scarf at Hanson’s because she was already there buying other things.

All of these choices could be true, but only one is likely to be true based on the evidence in the passage.

Maybe Rajita doesn’t know where to shop (choice a); maybe she has no idea that Lambert’s and Sam’s have the same merchandise at better prices. But there is no evidence of this in the passage. The same is true of choices b, d, and e; they may be true, but there is no evidence in the passage. (We know Sam’s regular price

C R I T I C A L R E A S O N I N G

c is a logical conclusion based on the passage. If Hanson’s sale price is \$35, nearly twice the price for the same merchandise from Sam’s, you will probably pay more for most items at Hanson’s.

On the exam, you will also see questions where several conclusions can be drawn from a series of prem-ises, and you must determine which of the conclusions presented is not logical based on the evidence (prem-ises) provided. This was the case with question 9 from the pretest:

9. When romance novels were located in the back of the bookstore, they accounted for approximately 6%

of total sales. Since we moved romance novels close to the front of the store and put several books on display, sales of romance novels have increased to 14% to 18% of total sales.

All of the following conclusions can logically be drawn from this argument EXCEPT a. customers who bought one romance novel are likely to come back for another.

b. customers are more likely to buy books located near the front of the bookstore than at the back.

c. the display caught the interest of people who might not have otherwise purchased a romance novel.

d. customers believe that bookstores put their best books near the front of the store.

e. sales of romance novels may increase even more if the section were moved all the way to the front.

To answer this question correctly, you must evaluate each option in light of the evidence. In this case, the only conclusion that does not logically follow from the premises is a. The significant increase in sales after the relocation of the books indicates that customers are more likely to buy books at the front of the store (choice b) and that the display may have caught the interest of people who might not otherwise purchase a romance novel (choice c). It is also logical to conclude that sales would further increase if the books were moved even farther toward the front of the store (choice e). Choices b and e and the increase in sales all sug-gest that customers believe the best books are near the front of the store (choice d). The only conclusion that cannot logically be drawn from this scenario is that customers will come back to purchase more romance nov-els (choice a). There is no evidence here for this conclusion; nothing in the data indicates repeat purchases for customers.

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E v a l u a t i n g A r g u m e n t s

Many GMAT critical reasoning questions will ask you to evaluate an argument. This usually means you will have to assess the logic of the argument and/or the effectiveness of the evidence provided in support of the conclusion. To do this, you need to consider three elements of effective arguments:

Qualifiers. Does the argument allow for exceptions, or make an absolute claim?

Evidence. Does the argument provide strong evidence to accept the claim?

Logic. Does the argument present reasonable premises, or is it based on faulty logic?

Qualifiers

Qualifiers are words and phrases that limit the scope of a claim to help make an argument more valid (more likely to be true). For example, take a look at the following arguments:

In document LearningExpress s EXAM SUCCESS GMAT. In Only 4 Steps! (Page 101-106)