Critical Reasoning

critical reasoning implies critical thinking or clear thinking.

We think critical reasoning involves three important components of reasoning. These components are as follows:

• Critical reasoning is thinking for yourself.
• Critical reasoning is informed reasoning.
• Critical reasoning is critical self-reflection.

Critical reasoning is about arguments: their construction, analysis and evaluation. It is therefore important to understand what we mean by the term “argument”. The term “argument” can be used in three different senses:

1. a quarrel or fight between two or more people
2. a group of statements intended to establish the truth or acceptability of a claim
3. an exchange between two or more people who disagree with each other, in which each person gives reasons to support his or her position.

To bring out the different senses of the term “argument”, consider the sentence:

The philosophy lecturer had an argument.

If we use sense (1) above, the sentence might continue as follows:

The philosophy lecturer had an argument with a sociology lecturer in the local bar and was taken to hospital.

If we use sense (2) above, the sentence might continue as follows:

The philosophy lecturer had an argument which, he claimed, established the truth of the proposition “God exists”.

If we use sense (3) above, the sentence might continue as follows:

The philosophy lecturer had an argument with his colleagues after they disputed his claim that God exists.

When we talk about an argument in critical reasoning, we do not use it in sense (1). That is, we do not mean a quarrel between two persons. In critical reasoning, the term “argument” is used in senses (2) and (3) only.

Typical questions that appear in critical reasoning include strengthening an argument, weakening an argument, identifying the assumption of an argument, and evaluating an argument. A Critical Reasoning (CR) argument is usually structured into facts (also sometimes referred to as premises) and a conclusion. It is important that you are able to identify the parts of an argument. Your job is never to question the facts of the argument. You can question the gap between the facts and the conclusion. This gap can be called an assumption the writer makes in his/her argument. In other words, what did the writer have to believe to be true in order to reach the conclusion, as based on the premise(s)? There are many CR questions that require you to identify an assumption. It can get complex, but here are some tips to simplify matters.

1. Simplify language.

You know from your work on SC that the shortest, simplest answer is often the best answer. It is as if the test makers take these rules they have established in SC and throw them out the window when they write CR and RC problems. They write their sentences in the most confusing way possible. If you can simplify the language the test makers use, it can make your job easier.

2. Use your own words.

One way to simplify the language used in a question is to express it using your own words. This involves making very short notes to summarize each of the sentences in a CR passage. The purpose of this is to make the passage easier to understand. Your own words will be easier for you to understand than the difficult words chosen by someone who is trying to confuse you!

3. Understand what is being asked.

For example, let’s imagine a simple example in which the conclusion is that Rome is a pleasant city.

A common question would be: “Which of the following, if true, would most strengthen the above conclusion?”

Option A) There are many great art galleries in Rome.
Option B) Venice has many great restaurants.

Sometimes people are confused as to whether they have to consider if the options are true or not. You don’t have to do this. You can assume all the options are true. You don’t have to ask yourself whether it is actually true that Venice has many great restaurants. It’s clear that Option A would be the right answer, because it’s the only answer that actually applies to Rome. When the questions become more difficult, you can save time by remembering that it is not your job to consider whether the options are true or not when the question is worded this way.

Examples:

1. The program to control the entry of illegal drugs into the country was a failure in 1987. If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987. 

Question: The argument in the passage depends on which of the following assumptions?

Answer Choices:
A. The supply of illegal drugs dropped substantially in 1987.
B. The price paid for most illegal drugs by the average consumer did not drop substantially in 1987.
C. Domestic production of illegal drugs increased at a higher rate than did the entry of such drugs into the country.
D. The wholesale price of a few illegal drugs increased substantially in 1987.
E. A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price.

Answer: E

Answer Explanation: The only choice that must be true in order to conclude legitimately from the drop in wholesale price of illegal drugs that the program was a failure is choice E, the best answer. If the drop in price was caused by a drop in demand, there is no reason to suspect that there has been any increase in supply caused by drugs entering the country.

The other choices can be false without affecting the argument. The supply of illegal drugs need not have dropped (choice A), and the retail price could have dropped (choice B). The entry of illegal drugs could have risen at a higher rate than domestic production (choice C), and no illegal drug need have undergone a substantial price rise (choice D).

2. To persuade consumers to buy its personal computers for home use, SuperComp has enlisted computer dealers in shopping centers to carry its product and launched a major advertising campaign that has already increased public awareness of the SuperComp brand. Despite the fact that these dealers achieved dramatically increased sales of computers last month, however, analysts doubt that SuperComp’s products accounted for much of that increase.

Question: Which of the following, if true, best supports the claim that the analysts’ doubt is well founded?

Answer Choices:
A. In market surveys, few respondents who had been exposed to SuperComp’s advertising campaign said they thought there was no point in owning a home computer.
B. People who own a home computer often buy a second such computer, but only rarely do people buy a third computer.
C. SuperComp’s dealers also sell other brands of computers that are very similar to SuperComp’s but less expensive and that afford the dealers a significantly higher markup.
D. The dealers who were chosen to sell SuperComp’s computers were selected in part because their stores are located in shopping centers that attract relatively wealthy shoppers.
E. Computer-industry analysts believed before the SuperComp campaign began that most consumers who already owned home computers were not yet ready to replace them.

Answer: C

Answer Explanation: The passage states that the stores through which SuperComp is selling its computers are experiencing dramatically increased sales. Analysts doubt, however, that SuperComp’s plan for selling tis computers for home use is really working. The question asks you to identify a fact that justifies the analysts’ doubt.

Choice C is the best answer. If consumers who are drawn to a SuperComp dealer find less expensive alternatives that the dealer has a strong incentive to sell to them, the analysts’ doubt is justified, since it is likely that the increase in the dealer’s sales is due not to sales of SuperComp’s computers, but rather to sales of these other brands.