Logical Reasoning Chapter 2: The Basics of Logical Reasoning

Within a single-speaker stimulus the test makers can raise alternate viewpoints. One of the most frequently used constructions is to raise a viewpoint and then disagree with it. Are recognizable because they begin with but not limited to the following:

"Some people claim..." "Some people propose..." "Some people believe..." "Some argue that..." or "Some people argue that..." "Some critics claim..." "Some critics maintain..." "Some scientists believe..."

Uncovering Meaning: Context, Simplification, and Rephrasing (of Killer Sentences)

1. Slow down and relax when you find a convoluted sentence. Take your time as details matter and it is not only acceptable but advisable to spend time at critical points to get your facts straight. Be patient! Keep in mind all the information you need to unlock the meaning of the sentence. Maintain composure. 2. Recognize that killer sentences are really a package of connected thoughts, and thus you must break down the sentence into smaller component pieces. Use the punctuation marks (e.g., commas, dashes, semi-colons, and colons) in the sentence as natural separators and thus you can usually divide each sentence into smaller, more manageable sections. 3. Next, simplify the sentence by rephrasing. 4. Given that you know the sentence is a difficult one, make a mark on the stimulus (use the underline feature or a highlight color you reserve for confusing sections)

Argument defined

A set of statements wherein one statement is claimed to follow from or be derived from the others.

What is the difference between an assumption and an inference

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. An assumption occurs before the argument and inference is made after the argument is complete following the argument.

Notice that premises and conclusions can be presented in?

Any order- the conclusion can be first, last or in the middle and the relationship between the premises and conclusion remains the same regardless of the order of presentation. Also both can appear in the same sentence. If a conclusion is present, you must identify the conclusion prior to proceeding to the question stem. Remember, a fact set does not contain a conclusion; an argument must contain a conclusion.

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.

Analyzing the Stimulus

As you read the stimulus, initially focus on making a quick analysis of the topic under discussion and the general view of the author. However, do not assume that everything you know "outside" of the stimulus regarding the topic is true and applies to the stimulus. Make sure to read the entire stimulus very carefully. Analyze the structure of the stimulus: what pieces are present and how do those pieces relate to each other?

Counter-premise Indicators:

But, yet, however, on the other hand, admittedly, in contrast, although, even though, still, whereas, in spite of, despite, and after all. Note that some terms such as "After all" can appear on multiple indicator lists because the phrase can be used in a variety of ways. It is up to you to identify the exact role that the phrase is playing in the argument. Example: The US 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.

Dash [-]:

Dashes are extremely versatile, and are often substituted for other punctuation marks, but the purpose is typically to set apart a particular idea. Examples: The culmination of her career was a show at the Tate Modern-the premier modern art museum in England

Primary Objective #1:

Determine whether the stimulus contains an argument or if it is only a set of factual statements.

Additional Premise Indicators:

Furthermore, moreover, besides, in addition, what's more, and after all Example: 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.

Primary Objective #3:

If the stimulus contains an argument, determine whether the argument is strong or weak In logic, the terms "strong/weak", "good/bad", "valid/invalid" and "sound/unsound" are used to evaluate different aspects of arguments. For our purposes all of them will be interchangeable and all terms refer to the logical structure of the argument. The same holds true for the opposite weak/bad/invalid and unsound. An argument can be valid without being true.

Primary Objective #2:

If the stimulus contains an argument, identify the conclusion of the argument. If the stimulus contains a fact set, examine each fact.

Primary Objective #4:

Read closely and know precisely what the author said. Do not generalize! Words that should be noted regardless of where they appear: quality indicators, probability indicators, and quantity indicators

Approaching the Question- What to read first?

Read them in order: stimulus, question stem and answer choices

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.

What are the three parts to Logical Reasoning Questions:

Stimulus, Question Stem and Answer Choices

Raise and viewpoint and then disagree with it structure

Structure of the 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... There are some exceptions like: "Although some people claim..." (starts with "although") "It has been claimed that..." (drops the number and people) "Cigarette companies claim that..." (drops the number) The author can 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.

Recognizing Conclusions Without Indicators The easiest way to determine the conclusion in an argument is to use the Conclusion Identification Method:

Take the statements under consideration for the conclusion and mentally 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. (see example on page 45).

Semi-colon [;]:

The ideas of either side of this typically are related but also stand on their own as complete sentences. In this sense, this is stronger than a comma. Example: Professional athletes are paid for their time and services; amateur athletes are typically not paid.

Parentheses [()]:

The information in parentheses typically expands upon and adds additional information to the sentence. Example: I arrived just before the library closed at 4 P.M. (a surprisingly early closing time in my opinion)

One Confusing Indicator Form One of their favourite forms places a conclusion indicator and premise indicator back-to-back, separated by a common like: "Therefore, since..." "Thus, because..." "Hence, due to..."

The presence of the common 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), because higher debt has forced consumers to lower their savings, (banks now have less money to loan)"

The scope of an argument is

The range to which the premises and conclusion encompass certain ideas. An argument with a narrow scope is definite in its statements, whereas a wide scope argument is less definite and allows for a greater range of possibility.

Reference Words

These are words that refer back or forward to ideas in the stimulus without explicitly naming the idea, and their use allows a writer to avoid repeating the same idea. These words are used frequently which are: This/that/these/those, It, they/their/them, one/ones, and former/latter Example: "... But this is not true, ..." The key is to make sure that you always know what any isolated reference words are referring to

Colon [:]:

This typically precedes either an explanation of the point prior to the it, or introduces a list of some sort. Example: The tip on the company's violations came from an unlikely source: the company's CEO.

Truth versus Validity

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 word truthfulness of either the premises or the conclusion. In most cases, the LSAT makers will let you work under a framework where the premises are simply accepted as factual accurate 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 relation to the premises, not whether the conclusion in true in an absolute, real world sense.

Decoding Text Summarizing Stimuli

You want to reach a point where you read the stimulus, but then could still summarize it accurately if someone took the text away from you. How to break up a stimuli to shorter coherent parts: Original sentences to the summary "Editorial: The African penguin, which communicates with a loud donkey-like bray, is found only in the southern reaches of the continents, and typically keeps within 20 km of the coastline. Summary: There's penguin in Africa that lives in the south close the coast that is loud. "The species is suffering from declining numbers severe enough to qualify it as endangered, and their numbers have been hurt by tanker oil spills in their breeding grounds, which are near commercial shipping lanes. Summary: Penguin numbers are dropping and it's endangered. Oil spills in their breeding grounds are the issue. "For this reason the proposal to move those shipping lanes farther out to sea should be endorsed" Summary: We should approve the proposal to move the lanes farther out.

A premise

a fact, proposition or statement from which a conclusion is made. A premise gives a reason why something should be believed. To identify premises ask yourself, "What reasons has the author used to persuade me? Why should I believe this argument? What evidence exists?"

A conclusion

a statement or judgment that follows from one or more reasons. 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?"

Quality indicators

all, every, most, many, some, several, few, sole, only, not all, none

Fact sets

are a collection of statements without a conclusion. The lack of a strong reaction ("who cares?") is often an indication that you are not reading an argument but a set of facts.

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, and we know this by

Counter-premises (also called adversatives)

bring up points of opposition or comparison. By raising the counter-premise and then addressing the complaint in a direct fashion, the author can eliminate a possible future line of attack against the argument and minimize the damage that would be done by the objection if it were raised elsewhere. They can also be ideas that compare and contrast with the argument, or work against a previously raised point. In this sense, the general counter-premised concept discusses an idea that is in some way different from another part of the argument. The author usually indicates that the counter-premise is not relevant or is outweighed by other considerations thus, not integral to the author's argument structure.

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 the premises? When evaluating arguments strength, the question you must always ask yourself is: Do the given facts support the conclusion? When flaws are present in the stimuli, the error normally occurs when the author draws a conclusion from the premises. When analyzing arguments, track the strength of the conclusion relative to the premises. A conclusion can, independent of the premises, be strong or weak. 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.

Complex arguments

contain more than one conclusion. In these instances, one of the conclusions is the main conclusion and the other one is a subsidiary conclusion (or sub-conclusion).

"Initial conclusion"

does not mean that it is the first conclusion presented in the argument. Instead, it means it is a base, or starting, conclusion for the argument. As noted previously, the order of the premises and conclusion is not important. Thus, a statement can be both a conclusion for one argument and a premise for another. Example: Because the Vikings have the best running back 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).

A simple argument

does not mean that the argument is easy to understand. Simple in this context means that the argument contains only a single conclusion.

The phrase "for example"

is a very helpful one because it typically expands and clarifies the idea that immediately precedes it. Thus, the main idea of the sentence (or of a stimulus) is not usually in the "for example" section, but instead just before it.

Probability indicators

must, will, always, not always, probably, likely, would, not necessarily, could, rarely and never

Quantity indicators

refer to the amount or quantity in the relationship. Probability indicators refer to the likelihood of occurrence, or the obligation present.

Comma [,]:

they appear in many sentences, and usually are used to separate ideas in some manner. As such, they are natural stopping points, and help divide a sentence into smaller pieces. Two commons in a sentence often bookend a standalone idea that is related to but separate from the main idea being expressed.

LSAT stimuli falls into two distinct categories:

those containing an argument and those that are just a set of facts.

Conclusion indicators:

thus, therefore, hence, consequently, as a result, so, accordingly, clearly, must be that, shows that, conclude that, follows that, and for this reason