# Mary has a firm command of the subject matter because she has studied it seriously

Exercise A. Identify Reasoning

In this exercise you will be given a list of items and asked to determine which one is reasoning and which one is not. Please indicate your answer in the space to the right of the word “Answer”.

Example:

Which of the following is reasoning and which is not?

1. Mary has a firm command of the subject matter because she has studied it seriously.

1. Mary has studied math for many years. She has a firm command of math and has won several prizes from math competitions.

Answer: No, this is not reasoning.

Which of the following is reasoning and which is not?

1. People want their appliances to be quiet. Yet, at the same time, they think that more noise means more power.

1. There is more and more concern about the noise in our environment. One reason is that our environment keeps getting noisier and noisier.

1. The people of Northern Ireland are fed up with the violence that has wrecked their country. Support for the IRA and for militant Protestant groups is the lowest it has ever been.

1. Anyone who works hard will be successful. Nancy works hard. Therefore, she will be successful.

1. Engineers can perform sound audits on machines to determine the noise produced by each moving part. First, they measure the noise level of the complete machine. Then, they disable different parts to measure the noise of each individual part of the machine.

1. Fortunately, the ordeal ended happily. The right people appeared at the appropriate time, and even their wrong turns led them to safety. It was a miracle.

1. Beethoven was musically gifted because Beethoven was deaf and all deaf persons are musically gifted.

1. Our galaxy is a huge, flat spiral system that rotates like a wheel, and the myriads of stars move around its center somewhat as the planets revolve around our sun.

1. Julie must be very patriotic. She has a huge American flag covering one wall of her dorm room.

1. Some animals that live in Kenya are endangered because lions are endangered animals and lions live in Kenya.

Exercise B. Identify Premise and Conclusion

In this exercise you will be given a list of reasoning examples and for each of these examples you are asked to determine its conclusion by copying the statement of conclusion in the space to the right of the word “Answer”.

Example:

What is the conclusion in the following reasoning?

“Mary has a firm command of the subject matter because she has studied it seriously.”

Answer: Mary has a firm command of the subject matter.

1. What is the conclusion in the following reasoning?

Government aid to poor countries often does more harm than good. The money is often siphoned off by corrupt officials, used to benefit urban dwellers at the expense of farmers, or invested in prestigious but economically nonviable projects.

1. What is the conclusion in the following reasoning?

Taxes on consumption, such as a sales tax, are not as intrusive as the income tax. And because they are paid only if one chooses to buy the product, they are more nearly voluntary than the income tax. For both reasons, taxes on consumption are preferable.

1. What is the conclusion in the following reasoning?

Random testing of workers for drug use is a bad idea. For one thing, the tests (urine samples, breathalyzers, etc.) are extremely intrusive. For another thing, such testing is unnecessary. If drugs are affecting an employee’s performance, the employer can discipline or fire him for poor performance. If drug use is not affecting his performance, then it is none of the employer’s business.

1. What is the conclusion in the following reasoning?

A course taught with grades provides the best learning environment. Students need to know what is expected of them, and most students will learn the material only if they have an external incentive.

1. What is the conclusion in the following reasoning?

College basketball is more exciting to watch than pro basketball. The level of skill is nearly the same. And because the college season has less than half as many games, and a much smaller percentage of college teams qualify for the post-season playoffs, college players put more energy and emotion into every game.

1. What is the conclusion in the following reasoning?

Since refrigerators consume about seven percent of all electricity in the country, we could achieve a significant reduction in electricity consumption if we all stopped eating.

1. What is the conclusion in the following reasoning?

The embryo inside a hen’s egg must receive oxygen to survive and develop. So despite the apparent solidity of the eggshell, it must have holes large enough to allow the passage of oxygen molecules.

1. What is the conclusion in the following reasoning?

Since there are probably at least ten million stars in our galaxy that have planets capable of supporting life, it is likely that life has evolved on at least some of them.

1. What is the conclusion in the following reasoning?

If you want to see deer in the woods, you have to be quite. Deer are intimidated animals and they tend to run when they hear noise.

1. What is the conclusion in the following reasoning?

A fall in interest rates will stimulate the stock market. Because, either investors bid up share prices when interest rates fall, or, lower interest rates mean lower yields on investments other than stocks.

Exercise C. Identify Deductively Valid and Invalid Reasoning

In this exercise you will be given a list of reasoning examples and for each of these examples you are asked to determine whether it is deductively valid or invalid. Please indicate your answer by putting “deductively valid” or “deductively invalid” in the space to the right of the word “Answer”.

Example: Which of the following is deductively valid and which is not?

1. Mary has a firm command of math because she has studied it seriously.

1. Mary has a firm command of math because everyone who studies math seriously has a firm command of math and Mary studies math seriously.

Which of the following is deductively valid and which is not?

1. My husband, like all the members of his family, is a compulsive talker, because he drinks too much coffee and, thus, has too much caffeine in his system.

1. Ottawa is the capital of Canada. The capital of Canada is in the eastern part of Canada. Therefore, Ottawa is in the eastern part of Canada.

1. All Indians are Buddhists. All Buddhists have two heads. Beethoven was an Indian. Hence, Beethoven had two heads.

1. Ninety-nine percent of deaf persons have musical talent. Beethoven was deaf. Therefore, Beethoven had musical talent.

1. The mass extinction of dinosaurs at the end of the Jurassic occurred not all at once, but in steps over millions of years. This was due to the fact that there was either a change in climate or epidemics made possible by the emergence of land bridges

1. Either the next Olympics will be held in Atlanta, Georgia or in Athens, Greece. It won’t be held in Athens, Greece. Therefore, it will be held in Atlanta, Georgia.

1. The mass extinction of dinosaurs at the end of the Jurassic occurred not all at once, but in steps over millions of years. This was due to a sudden disaster that occurred at this time.

1. I will be able to travel to Europe only if the exchange rate is favorable. The exchange rate does not remain favorable. So, I will not be able to go to Europe.

1. Only if a candidate has lots of money can he run for President. Donald Trump is running for President. So, Donald Trump has lots of money.

1. All mammals are animals that breathe by means of lungs. All whales are mammals. All whales are animals that breathe by means of lungs.

Exercise D. Identify Popular Deductive Fallacies

In this exercise you will be given a list of fallacious reasoning examples and for each of these examples you are asked to determine specifically what fallacy it commits. Please type the name of the fallacy in the space to the right of the word “Answer”.

Example: To what fallacy each of the follow reasoning commits?

1. This airplane is made in Seattle. Therefore, all of its parts are made in Seattle.

Answer: Distorted Analysis (Invalid Whole-To-Part Inference)

1. Yoda must exist. No one has proved that he doesn’t.

Answer: Argument from the Absence of Proof (A proposition hasn’t been proven false; therefore, it is true).

To what fallacy each of the follow reasoning commits?

1. Women can’t be effective soldiers. I was just brought up to believe so.

1. The theory that light waves travel in a medium need not be considered; it is no longer accepted by most physicists.

1. You’re either for us or against us. If you don’t sign this petition, we’ll know where you stand.

1. Alger Hiss couldn’t have been a spy for the Russians. I just can’t imagine him betraying his country.

1. America needs a space program. After our flights to the moon ended in the 1970s, the country slipped into recession and economic malaise.

1. Conventional bombs did more damage in Second World War than nuclear bombs. Thus, a conventional bomb is more dangerous than a nuclear bomb.

1. Scientists have not been able to show that there is no planet beyond Pluto. This means that it’s likely that there is a planet beyond Pluto.

1. After the new power line went in, one of Farmer Brown’s cows died of leukemia. Microwave radiation from the lines must have been the cause.

1. An estimated 25% of Americans over the age of 18 believe in astrology. That is roughly 75,000,000 people. Therefore, there must be some truth to astrology!

1. Good students will study and learn without the threat of an exam, and bad students won’t study and learn even with the threat of an exam. So, exams serve no purpose.

1. I don’t thinking that Hilary cheated on the exam. I can’t imagine that she would be dishonest.

1. You play for the Chicago Philharmonic Orchestra? That’s the best orchestra in the world, so you must be the best violinist in the world.

1. The Strategic Defense Initiative can’t possibly work. There’s no way the computer programmers can prove there are no bugs in their programs.

1. Almost all peoples in the world believe in the existence of some kind of deity. Therefore, God must exist.

1. You are going to have to make up your mind. Either you decide that you can afford this car, or you decide you are going to walk to work for a while.

1. I am going to wear a purple sweater to the game tomorrow because each time I wore a purple sweater to a game and my team won the game.

1. You play violin for the Chicago Philharmonic Orchestra? That is the best orchestra in the world. You must be the best violinist in the world.