PHI-130: Critical Reasoning/Module 4/Activities
Learning Pathway 4 has five activities. The Journal activity and the quizzes have an answer key. Once you have completed the journal entry, you can use the key to evaluate how successful you were in meeting the learning objectives. While the assessments are optional, and the grades will not be directly related to whether or not you receive credit for this course, completing them will help you gauge your progress and prepare for the TECEP© exam.
Journal Assignment 7
Using the readings and your online resources, answer the following questions:
- In your own words, explain the difference between deductive and inductive arguments. Write down two examples of each.
- Explain the difference between valid deductive arguments and invalid deductive arguments and then write down two examples of each.
- In your online references, identify the differences between three major types of inductive arguments. Name each type and write down examples of each.
- What is the difference between a valid argument and a sound argument? Write down two examples of each.
Answer Key - Journal Assignment 7
Quiz 7
1. You can have a sound argument even if your premises are false.
_____ TRUE _____ FALSE2. A statement is any claim that either asserts or denies a state of affairs in the world.
_____ TRUE _____ FALSE3. Inductive arguments are arguments that go from the general to the particular.
_____ TRUE _____ FALSE4. An argument is any group of sentences that describes a situation.
_____ TRUE _____ FALSE5. An argument is a series of statements where one or more of these statements is/are intended to establish the truth or acceptability of the conclusion.
_____ TRUE _____ FALSE6. An argument must have at least three premises.
_____ TRUE _____ FALSE7. A conclusion is the main claim or point in an argument that the premises are intended to prove.
_____ TRUE _____ FALSE8. A good convincing argument is a valid argument. That is, since you accept that the premises are true, the conclusion must also be true.
_____ TRUE _____ FALSE9. A premise is a reason offered in support of an argument’s conclusion.
_____ TRUE _____ FALSE10. A good, convincing argument is a sound argument. That is, since you accept all the premises are true, you must accept the conclusion is true.
_____ TRUE _____ FALSE
Quiz 8
Identify the following arguments:
E = Empirical; V = Value
1. ___ If it rains today, the cricket match will be cancelled. It is raining today. Therefore, the cricket match is cancelled.
2. ___ My car is out of petrol. Therefore, it won’t start.
3. ___ Animals feel pain just as we do. It is only because we feel pain that it matters how others treat us. The capacity to feel pain is the origin of morality. Thus, the way we treat animals must be a matter of moral concern for us.
4. ___ Abortion is fully justified because a fetus is not a moral agent. Moreover, a fetus cannot make rational decisions.
5. ___ Affirmative action cannot be justified. First, it amounts to reverse discrimination. Second, it begets racial conflicts. Finally, it is a short-sighted solution to redress the wrongs of the past.
6. ___ The price of petrol will go up, if there is conflict in the Middle East. There is conflict in the Middle East. Therefore, the price of petrol will increase.
Identify the following in terms of soundness and validity:
1. Are all valid arguments sound?
______ yes ______ no2. Can a valid argument result in a false conclusion?
______ yes ______ no3. Are all true statements valid?
______ yes ______ no4. If you can knit, you can crochet. Sally can knit, therefore Sally can crochet.
______ sound _______ valid _____ neither5. In order for an argument to be sound, it requires that its premises be true and its form valid.
______ yes ______ no
Quiz 9
What kind of statement is the following:
D = Deductive; I = Inductive
1. ___ More doctors smoke Marlboros than any other cigarette. They must be good for your health.
2. ___ All plants need water to grow. If my philodendron does not get water, it will die.
3. ___ Desert plants require little water. If the drought does not last, the cactus will survive.
4. ___ Meteorologists predicted rain for today; it must be raining.
5. ___ The man I saw break into the apartment was wearing a hoodie. Philip is wearing a hoodie. He must be the man I saw.
6. ___ Only hippies wear Birkenstocks. Jake is wearing Birkenstocks. Jake must be a hippie.
7. ___ Blondes have more fun. I should dye my hair blonde.
8. ___ The last three dresses Jane wore were red, she will likely be wearing red again today.
9. ___ The logical method of science is inductive. Induction is fallibilistic and never reaches absolute certainty. Therefore I can’t trust everything science tells me.
10. ___ Melissa is a fashion model. Most models are tall and slim. Melissa must be tall and slim.
11. ___ Artists tend to be left handed. Joel is left-handed. Joel must be an artist.
Quiz 10
What kind of statement is the following:
D = Deductive; I = Inductive
1. ___ Jane and Joe left their crayons out in the sun yesterday and they melted. If they leave them out again today, they will melt again.
2. ___ All men are mortal, Socrates is a man, therefore Socrates is mortal.
3. ___ The stock market has risen every day for the last two months. I should invest in the stock market because it will probably continue to rise.
4. ___ Aches and fever are symptoms of the flu. Billy has aches and a fever. He must have the flu.
5. ___ All fruits grow on trees, therefore all apples grow on trees.
6. ___ All numbers ending in 5 or 0 are divisible by 5. The number 45 ends in 5 therefore it is divisible by 5.
7. ___ Most puppies bark at night. I need my sleep so I shouldn’t get a puppy because he will keep me up all night.
8. ___ Since all squares are rectangles and all rectangles have four sides, then all squares have four sides.
9. ___ Complicated things in the world are evidence that they were created by an intelligent designer. The world evidences great complexity and design. It must have been made by an intelligent being.
10. ___ Since all mammals nurse their young, then all whales nurse their young.
11. ___ The mailman has come at 1 pm every day this summer. The mailman will come at 1 pm today.
