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inferences/conclusions Objective:

Look again at the question:

1. Most serious students are happy students, and most serious students go to graduate school. Furthermore, all students who go to graduate school are overworked.

Which one of the following can be properly inferred from the statements above?

(A) Most overworked students are happy students.

(B) Some happy students are overworked.

(C) All overworked students are serious students.

(D) Some unhappy students go to graduate school.

(E) All serious students are overworked.

Pick what you think is the right answer (unimportant whether you get it right).

Answer Choice: __________

Reason: ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________.

Regardless of your answer, I want you to say in your own word what you think the LSAT is testing here?

_____________________________________________________________________________________________________________________________________________________________________________________________________________________________.

I have no way of knowing what your answer was and what your reasoning was, but I think it is most important that you understand what the LSAT is looking for...

The LSAT is NOT testing your knowledge of “student happiness” -- No LSAT prep book includes information about “student happiness” for you to memorize - the LSAT is testing your REASONING SKILLS!

So, if the question is asking you to come up with an inference/conclusion (like the question above), then there is no analysis of reasoning necessary - you treat each statement provided as a 100% true fact, regardless of the factual accuracy in reality.

An argument can be valid without being true. For example, the following has a valid argument structure but is not “true” in a real world sense:

“All birds can fly. An ostrich is a bird. Therefore, an ostrich can fly.”

Sample Question From The XXXX, XXXX LSAT:

When pregnant lab rats are given caffeine equivalent to the amount a human would consume by drinking six cups of coffee per day, an increase in the incidence of birth defects results. When asked if the government would require warning labels on products containing caffeine, a spokesperson stated that it would not because the government would lose credibility if the finding of these studies were to be refuted in the future.

(A) A warning that applies to a small population is inappropriate.

(B) Very few people drink as many as six cups of coffee a day.

(C) There are doubts about the conclusive nature of studies on animals.

(D) Studies on rats provide little data about human birth defects.

(E) The seriousness of birth defects involving caffeine is not clear.

Which of the following is most strongly suggested by the government's

statement above?

STATEMENT: An expression of a single fact, idea, thought, or opinion.

One of those “good habits” we discussed earlier is to divide sentences into separate statements, so it will be much easier to analyze.

Every stimulus has multiple statements (either premises or the conclusion). Since each sentence has either one or more statements, in order to better analyze the stimulus, you should learn to separate statements.

To separate each statement in a sentence, just ask yourself: “if I make this part of the sentence into a sentence by itself, does it still ‘make sense’?”

Hint:

First, separate statements by placing [brackets] around each individual statement (if there’s only one statement, bracket the whole sentence), then write each statement by itself.

Sometimes you may have to change some words around to make it grammatical; for example, to make it present tense instead of past tense—this is fine as long as you don’t change it too much.

I should grab a sweater because I heard that it might rain today, even though it looks sunny now.

[I should grab a sweater] because [I heard that it might rain today], even though [it looks sunny now].

Statement 1: I should grab a sweater.

Statement 2: I heard that it might rain today.

Statement 3: it looks sunny now.

Premise Indicators because

since

for

for example

for the reason that

in that

given that

as indicated by

due to

owing to

this can be seen from we know this by

Conclusion Indicators thus

therefore

hence

consequently as a result

so accordingly clearly

must be that shows that conclude that follows that for this reason

Make sure to memorize these word lists. Recognizing argument elements is critical!

When you are reading, always be aware of the presence of the words listed

Here are more examples of premise and conclusion indicators in use:

“The economy is in tatters. Therefore, we must end this war.”

“Therefore” introduces a conclusion; the first sentence is a premise.

“We must reduce our budget due to the significant cost overruns we experienced during production.”

“due to” introduces a premise; “We must reduce our budget” is the conclusion.

“Fraud has cost the insurance industry millions of dollars in lost revenue. Thus, congress will pass a stricter fraud control bill since the insurance industry has one of the most powerful lobbies.”

This argument contains two premises: the first premise is the first sentence and the second premise follows the word “since” in the second sentence; the conclusion is “congress will pass a

Important note: premises and conclusions can be constructed without indicator words present.

stricter fraud control bill.”

Notice that premises and conclusions can be presented in any order—the conclusion can be first or last, and the relationship between the premises and the conclusion remains the same regardless of the order of presentation. For example, if the order of the premise(s) and conclusion was switched in any of the examples above, the logical structure of the argument would not change.

Also notable is that the premises and the conclusion can appear in the same sentence, or be separated out into multiple sentences. Whether the ideas are together or separated has no effect on the logical structure of the argument.

Because the job of the test makers is to determine how well you can interpret information, they will sometimes arrange premise and conclusion indicators in a way that is designed to be confusing. One of their favorite forms places a conclusion indicator and premise indicator back-to-back, separated by a comma, as in the following examples:

“Therefore, since...” “Thus, because...” “Hence, due to...”

Premise and Conclusion Recognition Mini-Drill

Each of the following problems contains a short argument. For each argument, identify the conclusion and the premise(s). Answers on the next page.

“Given that the price of steel is rising, we will no longer be able to offer discounts on our car parts.”

“The political situation in Somalia is unstable owing to the ability of individual warlords to maintain powerful armed forces.”

“Since we need to have many different interests to sustain us, the scientists’ belief must be incorrect.”

“So, as indicated by the newly released data, we should push forward with our efforts to recolonize the forest with snowy tree crickets.”

“Television has a harmful effect on society. This can be seen from the poor school performance of children who watch significant amounts of television and from the fact that children who watch more than six hours of television a day tend to read less than non-television watching children.”

“The rapid diminishment of the ecosystem of the Amazon threatens the entire planet. Consequently, we must take immediate steps to convince the Brazilian government that planned development projects need to be curtailed for the simple reason that these development projects will greatly accelerate the loss of currently protected land.”

Features the premise indicator “given that.”

Premise: “Given that the price of steel is rising,”

Conclusion: “we will no longer be able to offer discounts on our car parts.”

2. Features the premise indicator “owing to.”

Premise: “owing to the ability of individual warlords to maintain powerful armed forces.”

Conclusion: “The political situation in Somalia is unstable”

3. Features the premise indicator “since.”

Premise: “Since we need to have many different interests to sustain us,”

Conclusion: “the scientists’ belief must be incorrect.”

4. Features the conclusion/premise form indicator “So, as indicated by.” Premise: “as indicated by the newly released data”

Conclusion: “we should push forward with our efforts to recolonize the forest with snowy tree crickets.”

5. Features the premise indicator “this can be seen from.” The second sentence contains two premises.

Premise 1: “This can be seen from the poor school performance of children who watch significant amounts of television”

Premise 2: “and from fact that children who watch more than six hours of television a day tend to read less than non-television watching children.”

Conclusion: “Television has a harmful effect on society.” Note how this sentence does not contain a conclusion indicator. Yet, we can determine that this is the conclusion because the other sentence contains two premises.

6. Features the conclusion indicator “consequently” and the premise indicator “for the simple reason that.” There are also two premises present.

Premise 1: “The rapid diminishment of the ecosystem of the Amazon threatens the entire planet.”

Premise 2: “for the simple reason that these development projects will greatly accelerate the loss of currently protected land.” Conclusion: “we must take immediate steps to convince the Brazilian

government that planned development projects need to be curtailed”

Additional premises are still, of course, premises. They may be central to the argument or they may be secondary. To determine the importance of the premise, examine the remainder of the argument.

Furthermore Moreover Besides

In addition What’s more

Following are two examples of additional premise indicators in use:

1. “Every professor at Fillmore University teaches exactly one class per semester. Fillmore’s Professor Jackson, therefore, is teaching exactly one class this semester. Moreover, I heard Professor Jackson say she was teaching only a single class.”

The first sentence is a premise. The second sentence contains the conclusion indicator “therefore” and is the conclusion of the argument. The first sentence is the main proof offered by the author for the conclusion. The third sentence begins with the additional premise indicator “moreover.” The premise in this sentence is non-essential to the argument, but provides additional proof for the conclusion and could be, if needed, used to help prove the conclusion separately (this would occur if an objection was raised to the first premise).

2. “The city council ought to ease restrictions on outdoor advertising because the city’s economy is currently in a slump. Furthermore, the city should not place restrictions on forms of speech such as advertising.”

The first sentence contains both the conclusion of the argument and the main premise of the argument (introduced by the premise indicator “because”). The last sentence contains the additional premise indicator “furthermore.” As with the previous example, the additional premise in this sentence is non-essential to the argument but provides additional proof for the conclusion.

Counter-premise Indicators

When creating an argument, an author will sometimes bring up a counter- premise—a premise that actually contains an idea that is counter to the argument. At first glance, this might seem like an odd thing for an author to do. But by raising the counter-premise and then addressing the complaint in a direct fashion, the author can minimize the damage that would done by the objection if it was raised elsewhere.

Counter-premises can also be ideas that compare and contrast with the argument, or work against a previously raised point. In this sense, the general counter-premise concept discusses an idea that is in some way different from another part of the argument.

Counter-premise Indicators

But

Yet

However

On the other hand Admittedly

In contrast Although

Even though

Still

Whereas

In spite of Despite

After all

Following is an example of a counter-premise indicator in use:

1. “The United States prison population is the world’s largest and consequently we must take steps to reduce crime in this country. Although other countries have higher rates of incarceration, their statistics have no bearing on the dilemma we currently face.”

The first sentence contains a premise and the conclusion (which is introduced by the conclusion indicator “consequently”). The third sentence offers up a counter-premise as indicated by the word “although.”

Counter- premises, also called adversatives, bring up points of opposition or comparison.

Chapter Two: The Basics of Logical Reasoning

19

20

The PowerScore LSAT Logical Reasoning Bible

Additional Premise and Counter-Premise Recognition Mini-Drill

Each of the following problems contains a short argument. For each argument, identify the conclusion, the premise(s), and any additional premises or counter-premises. Answers on the next page.

Wine is made by crushing grapes and eventually separating the juice from the grape skins. However, the separated juice contains impurities and many wineries do not filter the juice. These wineries claim the unfiltered juice ultimately produces a more flavorful and intense wine. Since these wine makers are experts, we should trust their judgment and not shy away from unfiltered wine.

Phenylketonurics are people who cannot metabolize the amino acid phenylalanine. There are dangers associated with phenylketonuria, and products containing phenylalanine must carry a warning label that states, “Phenylketonurics: contains phenylalanine.” In addition, all children in developed societies receive a phenylketonuria test at birth. Hence, at the moment, we are doing as much as possible to protect against this condition.

During last night’s robbery, the thief was unable to open the safe. Thus, last night’s robbery was unsuccessful despite the fact that the thief stole several documents. After all, nothing in those documents was as valuable as the money in the safe.

Additional Premise and Counter-Premise Recognition Mini-Drill Answer Key

1. Features the counter-premise indicator “however” and the premise indicator “since.”

Premise: “Wine is made by crushing grapes and eventually separating the juice from the grape skins.”

Counter-premise: “However, the separated juice contains impurities and many wineries do not filter the juice.”

Premise: “These wineries claim the unfiltered juice ultimately produces a more flavorful and intense wine.”

Premise: “Since these wine makers are experts,”

Conclusion: “we should trust their judgment and not shy away from

unfiltered wine.”

2. Features the additional premise indicator “in addition” and the conclusion indicator “hence.” In this problem the additional premise is central to supporting the conclusion.

Premise: “Phenylketonurics are people who cannot metabolize the amino acid phenylalanine.”

Premise: “There are dangers associated with phenylketonuria, and products containing phenylalanine must carry a warning label that states, ‘Phenylketonurics: contains phenylalanine.’ ”

Additional Premise: “In addition, all children in developed societies received a phenylketonuria test at birth.”

Conclusion: “Hence, at the moment, we are doing as much as possible to protect against this condition.”

3. Features the counter-premise indicator “despite”; the additional premise indicator “after all”; and the conclusion indicator “thus.” The additional premise serves to downplay the counter-premise.

Premise: “During last night’s robbery, the thief was unable to open the safe.”

Counter-premise: “despite the fact that the thief stole several documents.”

Additional Premise: “After all, nothing in those documents was as valuable as the money in the safe.”

Conclusion: “Thus, last night’s robbery was unsuccessful ”

Chapter Two: The Basics of Logical Reasoning

21

Chapter Two: The Basics of Logical Reasoning

The Logical Reasoning Section

The focus of this book is on the Logical Reasoning section of the LSAT, and each Logical Reasoning section contains a total of 24 to 26 questions. Since you have thirty-five minutes to complete the section, you have an average of approximately one minute and twenty-five seconds to complete each question. Of course, the amount of time you spend on each question will vary with the difficulty of each question and the total number of questions per section. For virtually all students the time constraint is a major obstacle, and as we progress through this book we will discuss time management techniques as well as time-saving techniques that you can employ within the section.

The Section Directions

Each Logical Reasoning section is prefaced by the following directions:

On average, you have 1 minute and 25 seconds to complete each question.

Assumptions are a critical part of LSAT Logical Reasoning, and we will talk about assumptions in more detail in a later chapter.

Here’s a good example of what they expect you to assume: when “television” is introduced in a stimulus, they expect you to know, among other things, what a TV show is, that TV can portray the make-believe or real, what actors do, and that TV is shown by beaming signals into TV sets in homes and elsewhere.

The question to the right, from the October 2003 LSAT, is presented for demonstration purposes only. The problem contains Formal Logic, which we will examine in great detail in a later chapter. For those of you who wish to try the problem now, the correct answer is listed in the first sidebar on the next page.

The correct answer to the problem on the previous page is answer choice (B). This is not an easy problem, but after you read through our chapter on Formal Logic this question will seem very reasonable.

The spectrum of topics covered by Logical Reasoning stimuli is quite broad. Previous stimuli topics have ranged from art to economics to medicine and science. According to the makers of the test, “the arguments are contained in short passages taken from a variety of sources, including letters to the editor, speeches, advertisements, newspaper articles and editorials, informal discussions and conversations, as well as articles in the humanities, the social sciences, and the natural sciences.” Further, LSAT question topics “reflect a broad range of academic disciplines and are intended to give no advantage to candidates from a particular background.”

LSAT stimuli fall into two distinct categories: those containing an argument and those that are just a set of facts. Logically speaking, an argument can be defined as a set of statements wherein one statement is claimed to follow from or be derived from the others. Consider the following short example of an argument:

All professors are ethical. Mason is a professor. So Mason is ethical.

The first two statements in this argument give the reasons (or “premises”) for accepting the third statement, which is the conclusion of the argument.

Fact sets, on the other hand, are a collection of statements without a conclusion, as in the following example:

“The Jacksonville area has just over one million residents. The Cincinnati area has almost two million residents. The New York area has almost twenty million residents.”

The three sentences above do not constitute an argument because no conclusion is present and an argument, by definition, requires a conclusion. The three sentences merely make a series of assertions without making a judgment. Notice that reading these sentences does not cause much of a reaction in most readers. Really, who cares about the city sizes? This lack of a strong reaction is often an indication that you are not reading an argument and are instead reading just a set of facts.

Identifying Premises and Conclusions

Literally, the premises give the reasons why the conclusion should be accepted. To identify premises, ask yourself, “What reasons has the author used to persuade me? Why should I believe this argument? What evidence exists?”

Conclusions, as summary statements, are supposed to be drawn from and rest on the premises. To identify conclusions, ask yourself, “What is the author driving at? What does the author want me to believe? What point follows from the others?”

Make sure to memorize these word lists. Recognizing argument elements is critical!

Arguments can contain more than one premise and one conclusion.

When you are reading, always be aware of the presence of the words listed

above. These words are like road signs; they tell you what is coming next. Consider the following example:

Humans cannot live on Venus because the surface temperature is too high.

As you read the first portion of the sentence, “Humans cannot live on Venus,” you cannot be sure if you are reading a premise or conclusion. But, as soon as you see the word “because”—a premise indicator—you know that a premise will follow, and at that point you know that the first portion of the sentence is a conclusion. In the argument above, the author wants you to believe that humans cannot live on Venus, and the reason is that the surface temperature is too high.

In our daily lives, we make and hear many arguments. However, unlike on the LSAT, the majority of these arguments occur in the form of conversations (and when we say “argument,” we do not mean a fight!). Any LSAT argument can be seen as an artificial conversation, even the basic example above:

Author: “Humans cannot live on Venus.”

Respondent: “Really? Why is that?”

Author: “The surface temperature of Venus is too high.”

If at first you struggle to identify the pieces of an argument, you can always resort to thinking about the argument as an artificial conversation and that may assist you in locating the conclusion.

Here are more examples of premise and conclusion indicators in use:

“The economy is in tatters. Therefore, we must end this war.”

“Therefore” introduces a conclusion; the first sentence is a premise.

“We must reduce our budget due to the significant cost overruns we experienced during production.”

“due to” introduces a premise; “We must reduce our budget” is the conclusion.

“Fraud has cost the insurance industry millions of dollars in lost revenue. Thus, congress will pass a stricter fraud control bill since the insurance industry has one of the most powerful lobbies.”

This argument contains two premises: the first premise is the first sentence and the second premise follows the word “since” in the second sentence; the conclusion is “congress will pass a

stricter fraud control bill.”

Notice that premises and conclusions can be presented in any order—the conclusion can be first or last, and the relationship between the premises and the conclusion remains the same regardless of the order of presentation. For example, if the order of the premise(s) and conclusion was switched in any of the examples above, the logical structure of the argument would not change.

Also notable is that the premises and the conclusion can appear in the same sentence, or be separated out into multiple sentences. Whether the ideas are together or separated has no effect on the logical structure of the argument.

If a conclusion is present, you must identify the conclusion prior to proceeding on to the question stem. Often, the reason students miss questions is because they have failed to fully and accurately identify the conclusion of the argument.

One Confusing Form

Because the job of the test makers is to determine how well you can interpret information, they will sometimes arrange premise and conclusion indicators in a way that is designed to be confusing. One of their favorite forms places a conclusion indicator and premise indicator back-to-back, separated by a comma, as in the following examples:

“Therefore, since...” “Thus, because...” “Hence, due to...”

A quick glance would seemingly indicate that what will follow is both a premise and a conclusion. In this instance, however, the presence of the comma creates a clause that, due to the premise indicator, contains a premise. The end of that premise clause will be closed with a second comma, and then what follows will be the conclusion, as in the following:

“Therefore, since higher debt has forced consumers to lower their savings, banks now have less money to loan.”

“Higher debt has forced consumers to lower their savings” is the premise; “banks now have less money to loan” is the conclusion. So, in this instance “therefore” still introduces a conclusion, but the appearance of the conclusion is interrupted by a clause that contains a premise.

Order of presentation has no effect on the logical structure of the argument. The conclusion can appear at the beginning, the middle, or the end of the argument.

Remember, a fact set does not contain a conclusion; an argument must contain a conclusion.

Premise and Conclusion Recognition Mini-Drill

Each of the following problems contains a short argument. For each argument, identify the conclusion and the premise(s). Answers on the next page.

“Given that the price of steel is rising, we will no longer be able to offer discounts on our car parts.”

“The political situation in Somalia is unstable owing to the ability of individual warlords to maintain powerful armed forces.”

“Since we need to have many different interests to sustain us, the scientists’ belief must be incorrect.”

“So, as indicated by the newly released data, we should push forward with our efforts to recolonize the forest with snowy tree crickets.”

“Television has a harmful effect on society. This can be seen from the poor school performance of children who watch significant amounts of television and from the fact that children who watch more than six hours of television a day tend to read less than non-television watching children.”

“The rapid diminishment of the ecosystem of the Amazon threatens the entire planet. Consequently, we must take immediate steps to convince the Brazilian government that planned development projects need to be curtailed for the simple reason that these development projects will greatly accelerate the loss of currently protected land.”

Premise and Conclusion Recognition Mini-Drill Answer Key

1. Features the premise indicator “given that.”

Premise: “Given that the price of steel is rising,”

Conclusion: “we will no longer be able to offer discounts on our car

parts.”

2. Features the premise indicator “owing to.”

Premise: “owing to the ability of individual warlords to maintain

powerful armed forces.”

Conclusion: “The political situation in Somalia is unstable”

3. Features the premise indicator “since.”

Premise: “Since we need to have many different interests to sustain

us,”

Conclusion: “the scientists’ belief must be incorrect.”

4. Features the conclusion/premise form indicator “So, as indicated by.” Premise: “as indicated by the newly released data”

Conclusion: “we should push forward with our efforts to recolonize the

forest with snowy tree crickets.”

5. Features the premise indicator “this can be seen from.” The second sentence contains two premises.

Premise 1: “This can be seen from the poor school performance of children who watch significant amounts of television”

Premise 2: “and from fact that children who watch more than six hours of television a day tend to read less than non-television watching children.”

Conclusion: “Television has a harmful effect on society.” Note how this sentence does not contain a conclusion indicator. Yet, we can determine that this is the conclusion because the other sentence contains two premises.

6. Features the conclusion indicator “consequently” and the premise indicator “for the simple reason that.” There are also two premises present.

Premise 1: “The rapid diminishment of the ecosystem of the Amazon threatens the entire planet.”

Premise 2: “for the simple reason that these development projects will greatly accelerate the loss of currently protected land.” Conclusion: “we must take immediate steps to convince the Brazilian

government that planned development projects need to be curtailed”

Additional Premise Indicators

Furthermore Moreover Besides

In addition What’s more

Following are two examples of additional premise indicators in use:

1. “Every professor at Fillmore University teaches exactly one class per semester. Fillmore’s Professor Jackson, therefore, is teaching exactly one class this semester. Moreover, I heard Professor Jackson say she was teaching only a single class.”

The first sentence is a premise. The second sentence contains the conclusion indicator “therefore” and is the conclusion of the argument. The first sentence is the main proof offered by the author for the conclusion. The third sentence begins with the additional premise indicator “moreover.” The premise in this sentence is non-essential to the argument, but provides additional proof for the conclusion and could be, if needed, used to help prove the conclusion separately (this would occur if an objection was raised to the first premise).

2. “The city council ought to ease restrictions on outdoor advertising because the city’s economy is currently in a slump. Furthermore, the city should not place restrictions on forms of speech such as advertising.”

The first sentence contains both the conclusion of the argument and the main premise of the argument (introduced by the premise indicator “because”). The last sentence contains the additional premise indicator “furthermore.” As with the previous example, the additional premise in this sentence is non-essential to the argument but provides additional proof for the conclusion.

Counter-premise Indicators\

But

Yet

However

On the other hand Admittedly

In contrast Although

Even though

Still

Whereas

In spite of Despite

After all

Following is an example of a counter-premise indicator in use:

1. “The United States prison population is the world’s largest and consequently we must take steps to reduce crime in this country. Although other countries have higher rates of incarceration, their statistics have no bearing on the dilemma we currently face.”

The first sentence contains a premise and the conclusion (which is introduced by the conclusion indicator “consequently”). The third sentence offers up a counter-premise as indicated by the word “although.”

Each of the following problems contains a short argument. For each argument, identify the conclusion, the premise(s), and any additional premises or counter-premises. Answers on the next page.

Wine is made by crushing grapes and eventually separating the juice from the grape skins. However, the separated juice contains impurities and many wineries do not filter the juice. These wineries claim the unfiltered juice ultimately produces a more flavorful and intense wine. Since these wine makers are experts, we should trust their judgment and not shy away from unfiltered wine.

Phenylketonurics are people who cannot metabolize the amino acid phenylalanine. There are dangers associated with phenylketonuria, and products containing phenylalanine must carry a warning label that states, “Phenylketonurics: contains phenylalanine.” In addition, all children in developed societies receive a phenylketonuria test at birth. Hence, at the moment, we are doing as much as possible to protect against this condition.

During last night’s robbery, the thief was unable to open the safe. Thus, last night’s robbery was unsuccessful despite the fact that the thief stole several documents. After all, nothing in those documents was as valuable as the money in the safe.

Additional Premise and Counter-Premise Recognition Mini-Drill Answer Key

1. Features the counter-premise indicator “however” and the premise indicator “since.”

Premise: “Wine is made by crushing grapes and eventually separating the juice from the grape skins.”

Counter-premise: “However, the separated juice contains impurities and many wineries do not filter the juice.”

Premise: “These wineries claim the unfiltered juice ultimately produces a more flavorful and intense wine.”

Premise: “Since these wine makers are experts,”

Conclusion: “we should trust their judgment and not shy away from

unfiltered wine.”

2. Features the additional premise indicator “in addition” and the conclusion indicator “hence.” In this problem the additional premise is central to supporting the conclusion.

Premise: “Phenylketonurics are people who cannot metabolize the amino acid phenylalanine.”

Premise: “There are dangers associated with phenylketonuria, and products containing phenylalanine must carry a warning label that states, ‘Phenylketonurics: contains phenylalanine.’ ”

Additional Premise: “In addition, all children in developed societies received a phenylketonuria test at birth.”

Conclusion: “Hence, at the moment, we are doing as much as possible to protect against this condition.”

3. Features the counter-premise indicator “despite”; the additional premise indicator “after all”; and the conclusion indicator “thus.” The additional premise serves to downplay the counter-premise.

Premise: “During last night’s robbery, the thief was unable to open the safe.”

Counter-premise: “despite the fact that the thief stole several documents.”

Additional Premise: “After all, nothing in those documents was as valuable as the money in the safe.”

Conclusion: “Thus, last night’s robbery was unsuccessful ”

Chapter Two: The Basics of Logical Reasonin

Many of the arguments we have encountered up until this point have had conclusion indicators to help you recognize the conclusion. And, many of the arguments you will see on the LSAT will also have conclusion indicators. But you will encounter arguments that do not contain conclusion indicators. Following is an example:

The best way of eliminating traffic congestion will not be easily found. There are so many competing possibilities that it will take millions of dollars to study every option, and implementation of most options carries an exorbitant price tag.

An argument such as the above can be difficult to analyze because no indicator words are present. How then, would you go about determining if a conclusion is present, and if so, how would you identify that conclusion? Fortunately, there is a fairly simple trick that can be used to handle this situation, and any situation where you are uncertain of the conclusion (even those with multiple conclusions, as will be discussed next).

Aside from the questions you can use to identify premises and conclusions (described earlier in this chapter), the easiest way to determine the conclusion in an argument is to use the Conclusion Identification MethodTM:

Take the statements under consideration for the conclusion and place them in an arrangement that forces one to be the conclusion and the other(s) to be the premise(s). Use premise and conclusion indicators to achieve this end. Once the pieces are arranged, determine if the arrangement makes logical sense. If so, you have made the correct identification. If not, reverse the arrangement and examine the relationship again. Continue until you find an arrangement that is logical.

Let us apply this method to the argument at the top of this page. For our first arrangement we will make the first sentence the premise and the second sentence the conclusion, and supply indicators (in italics):

Because the best way of eliminating traffic congestion will not be easily found, we can conclude that there are so many competing possibilities that it will take millions of dollars to study every option, and implementation of most options carries an exorbitant price tag.

Does that sound right? No. Let us try again, this time making the first sentence the conclusion and the second sentence the premise:

Because there are so many competing possibilities that it will take millions of dollars to study every option, and implementation of most options carries an exorbitant price tag, we can conclude that the best way of eliminating traffic congestion will not be easily found.

Clearly, the second arrangement is far superior because it makes sense. In most cases when you have the conclusion and premise backward, the arrangement will be confusing. The correct arrangement always sounds more logical.

Because the Vikings have the best wide receiver in football, they therefore have the best offense in football. Because they have the best offense in football, they will win the Super Bowl next year.

In this argument, the first sentence contains a premise followed by a conclusion. This initial conclusion is then used in the second sentence as a premise to make a larger conclusion:

Premise: “Because the Vikings have the best wide receiver in football,” Sub-Conclusion (conclusion of the previous premise/Premise for the

following conclusion): “they therefore have the best offense in

football.”

Main Conclusion: “they will win the Super Bowl next year.”

As we will see in Chapter Twelve while discussing Method of Reasoning questions, one of the most commonly used complex argument forms is to place the main conclusion in the first sentence of the argument, and then to place the sub-conclusion in the last sentence of the argument, preceded by a conclusion indicator. This form is quite useful since it tends to trick students into thinking the last sentence is the main conclusion.

Another form of complex argumentation occurs with two-speaker stimuli. In these questions, two separate speakers are identified, and each presents his or her own argument or comment. Here is an example from the June 2003 LSAT:

Anne: Halley’s Comet, now in a part of its orbit relatively far from the Sun, recently flared brightly enough to be seen by telescope. No comet has ever been observed to flare so far from the Sun before, so such a flare must be highly unusual.

Sue: Nonsense. Usually no one bothers to try to observe comets when they are so far from the Sun. This flare was observed only because an observatory was tracking Halley’s Comet very carefully.

In the argument above, each speaker presents premises and a conclusion. As often occurs with this form of question, the two speakers disagree.

One of the benefits of a two-speaker stimulus is that the test makers can introduce multiple viewpoints on the same subject. As you might imagine, the presence of multiple viewpoints tends to be confusing, and the extra viewpoints offer the test makers the opportunity to ask a wider variety of questions

A Commonly Used Construction

Even within a single-speaker stimulus the test makers can raise alternate viewpoints. One of the most frequently used constructions is to raise a viewpoint at the beginning of the stimulus and then disagree with it immediately thereafter. This efficiently raises two opposing views in a very short paragraph. These stimuli are recognizable because they often begin with the phrase, “Some people claim...” or one of the many variations on this theme, including but not limited to the following:

“Some people propose...”

“Many people believe...”

“Some argue that...” or “Some people argue that...” “Some critics claim...”

“Some critics maintain...”

“Some scientists believe...

The structure of this opening sentence is remarkably consistent in form, and adheres to the following formula:

A number (some, many, etc.) of people (critics, students, teachers, legislators, vegetarians, psychologists etc.) believe (claim, propose, argue, etc.) that...

Of course, there are exceptions, as with these opening sentences from previous LSATs:

“Although some people claim...” “It has been claimed that...” “Cigarette companies claim that...”(starts with “although”)

(drops the number and people) (drops the number)

The author can also break up the idea, by inserting contextual information, as in the following example:

“Some critics of space exploration programs claim that...”

The use of this device to begin a stimulus almost always leads to the introduction of the opposing view, as in the following partial stimulus from the October 2003 LSAT:

Editorialist: Some people propose that, to raise revenues and encourage conservation, our country’s taxes on oil, gasoline, and coal should be increased. Such a tax, however, would do more harm than good.

The editorialist uses the “Some people propose” device to introduce one opinion of taxes and then in the following sentence counters the idea with the view that turns out to be the editorialist’s main point (“Such a tax, however...”). The remainder of the problem went on to explain the reasoning behind the editorialist’s view.

Given the frequency with which this construction appears at the beginning of stimuli, you should learn to begin recognizing it now. We will again discuss this device in the Main Point section.

Truth versus Validity

So far, we have only identified the parts that are used to construct arguments. We have not made an analysis of the reasonableness or soundness of an argument. But, before moving on to argument analysis, you must be able to distinguish between two commonly confused concepts: validity and truth.

When we evaluate LSAT arguments, we are primarily concerned with validity. That is, what is the logical relationship of the pieces of the argument and how well do the premises, if accepted, prove the conclusion? We are less concerned with the absolute, real world truthfulness of either the premises or the conclusion. Some students will at first try to analyze every single LSAT statement on the basis of whether it is an absolutely true statement (does it happen as stated in the real world). For the most part, that is wasted effort. LSAT Logical Reasoning is primarily focused on whether the conclusion follows logically from a set of given premises. In many cases, the LSAT makers will let you work under a framework where the premises are simply accepted as factually accurate, and then you must focus solely on the method used to reach the conclusion. In a sense this could be called relative truthfulness—you are only concerned about whether the conclusion is true relative to the premises, not whether the conclusion is true in an absolute, real world sense. This is obviously a critical point, and one we will analyze later as we discuss different question types.

Argument Analysis

Once you have determined that an argument is present and you have identified the conclusion, you must determine if the argument is a good one or a bad one. This leads to the third Primary Objective:

To determine the strength of the argument, consider the relationship between the premises and the conclusion—do the premises strongly suggest that the conclusion would be true? Does the conclusion feel like an inevitable result of

In l

“The Jacksonville area has just over one million residents. Cincinnati has almost two million residents. The New York area has almost twenty million residents. Therefore, we should move to Jacksonville.”

The last sentence contains the conclusion, and makes this an argument. Notice how the presence of the conclusion causes you to react more strongly to the stimulus. Now, instead of just reading a set of cold facts, you are forced to consider whether the premises have proven the given conclusion. In this case the author asks you to accept that a move to Jacksonville is in order based on the population of the city. Do you think the author has proven this point?

When considering the above argument, most people simply accept the premises as factually accurate. There is nothing wrong with this (and indeed in the real world they are true). As mentioned moments ago, in LSAT argumentation the makers of the test largely allow authors to put forth their premises unchallenged. The test makers are far more concerned about whether those premises lead to the conclusion presented. In the argument above, there is no reason to doubt the accuracy of the premises, but even if we accept the premises as accurate, we still do not have to accept the conclusion.

Most people reading the argument above would agree that the conclusion is weak. Even though the premises are perfectly acceptable, by themselves they do not prove that “we should move to Jacksonville.” The typical reader will experience a host of reactions to the conclusion: Why Jacksonville—why not a city that is even smaller? What is so important about population? What about considerations other than population size? Because questions of this nature point to flaws in the argument, we would classify the argument as a poor one. That is, the premises do not prove the conclusion. As shown by this example, the acceptability of the premises does not automatically make the conclusion acceptable. The reverse is also true—the acceptability of the conclusion does not automatically make the premises acceptable.

The following is an example of a strong argument:

“Trees that shed their foliage annually are deciduous trees. Black Oak trees shed their leaves every year. Therefore, Black Oak trees are deciduous. ”

In this argument, the two premises lead directly to the conclusion. Unlike the previous argument, the author’s conclusion seems reasonable and inevitable based on the two premises. Note that the strength of this argument is based solely on the degree to which the premises prove the conclusion. The truth of the premises themselves is not an issue in determining whether the argument is valid or invalid.

Most people have come to believe that the word inference means probably true or likely to be true. Indeed, in common usage infer is often used in the same manner as imply. On the LSAT these uses are incorrect. In logic, an inference can be defined as something that must be true. Thus, if you are asked to identify an inference of the argument, you must find an item that must be true based on the information presented in the argument.

Earlier we discussed assumptions in the context of commonsense assumptions that you can bring into each problem. In argumentation, an assumption is simply the same as an unstated premise—what must be true in order for the argument to be true. Assumptions can often have a great effect on the validity of the argument.

Separating an inference from an assumption can be difficult because the definition of each refers to what “must be true.” The difference is simple: an inference is what follows from an argument (in other words, a conclusion) whereas an assumption is what is taken for granted while making an argument. In one sense, an assumption occurs “before” the argument, that is, while the argument is being made. An inference is made “after” the argument is complete, and follows from the argument. Both concepts will be discussed in more detail in later chapters, but for the time being you should note that all authors make assumptions when creating their arguments, and all arguments have inferences that can be derived from the argument.

because the stimulus is prefaced by a short identifier, such as Politician or Professor, or even a proper name such as Fran or Inez. The source of a stimulus can also be made clear by similar identifiers, such as Advertisement or Editorial.

LSAT students sometimes confuse the aim of the test makers with the way those aims are executed. We know that Law Services has an active interest in testing your ability to discern reasoning, both good and bad. The makers of the exam intentionally present flawed arguments because they want to test if you are easily confused or prone to be swayed illogical arguments. This often raises situations where you are presented with arguments that are false or seemingly deceptive in nature. This does not mean that the author of the piece is part of the deception. The role of an LSAT author is simply to present an argument or fact set. LSAT authors (as separated from the test makers) do not try to deceive you with lies. Although LSAT authors may end up making claims that are incorrect, this is not done out of a willful intention to deceive. Deception on the author’s part is too sophisticated for the LSAT—it is beyond the scope of LSAT stimuli, which are too short to have the level of complexity necessary for you to detect deception if it was intended. So, you need not feel as if the author is attempting to trick you in the making of the argument. This is especially true when premises are created. For example, when an LSAT author makes a premise statement such as, “19 percent of all research projects are privately funded,” this statement is likely to be accurate. An LSAT author would not knowingly create a false premise, and so, when examining arguments the likelihood is that the premises are not going to be in error and you should not look at them as a likely source of weakness in the argument. This does not mean that authors are infallible. LSAT authors make plenty of errors, but most of those errors are errors of reasoning that occur in the process of making the conclusion. In later chapters we will examine these flawed reasoning methods in detail.

Consider the following argument: “My mail was delivered yesterday, so it will also be delivered today.”

Although this argument is flawed (it could be Sunday and the mail will not be delivered), the author has not intentionally made this error. Rather, the author has made the conclusion without realizing that an error has occurred.

These word lists do not require memorization. They are presented to give you a broad idea of the type of words that can take on an added importance in LSAT questions.

Quantity Indicators all

every

most

many some several few sole only not all none

Probability Indicators must

will

always

not always probably likely should would

not necessarily could

rarely

never

Quantity indicators refer to the amount or quantity in the relationship, such as “some people” or “many of the laws.” Probability indicators refer to the likelihood of occurrence, or the obligation present, as in “The Mayor should resign” or “The law will never pass.” Many of the terms fit with negatives to form an opposing idea, for example, “some are not” or “would not.”

Words such as the Quantity and Probability Indicators are critical because they are a ripe area for the LSAT makers to exploit. There are numerous examples of incorrect answer choices that attempted to capitalize on the meaning of a single word in the stimulus and thus you must commit yourself to carefully examining every word on the test.