the plants
EXERCISES FOR PART THREE
I. What is wrong with the following statements?
1. Validity is when an argument is true; i.e., its premises are true and its conclusion is true.
2. An argument is valid when it is both sound and true.
3. Premises can be true or false; conclusions are sound or unsound.
4. An argument’s validity depends on the truth of its premises.
5. An argument’s soundness depends upon its form.
II. Determine whether the following statements are true or false, and why.
1. A valid argument can have false premises.
2. A sound argument can have a false conclusion.
3. If an argument is sound, then it must be valid.
4. All valid arguments are also sound arguments.
5. All sound arguments are also valid arguments.
6. If an argument has all true premises and a true conclusion, then it is sound.
7. A valid argument must have a true conclusion.
8. It is correct to say that an argument is true or false.
9. An invalid argument must have at least one false premise.
10. An invalid argument must have a false conclusion.
EXERCISES FOR PART FOUR
I. Find the valid forms:
1. If a then b
b
a
2. Not b
If a then b
Not a
3. a or b
If a then c
If b then d
If a then d
4. If a then b
If c then d
a or c
b or d
5. Not b
If b then a
Not a
6. If a then b
If c then d
If a then d
II. Symbolize the following arguments, putting them into standard form and determine whether they possess one of our five valid forms or our two formal fallacies. Watch for reversals of the “if-then” statement (e.g. a statement like “I will go if you go” needs to move the “if” part up front: “If you go then I will go” — “If y then i”; not “i if y.”)
1. Either my roommate is in the gym or she is in the cafeteria. But since you have found that she is not in the cafeteria, then she must be in the gym.
2. If everything we do is determined by forces in our environment then we never exercise free will. Thus, we never do exercise free will, because it has been proven that everything we do is determined by forces in our environment.
3. Entering this building is permitted if you have an identification tag. You are not permitted to enter this building, though, because you do not have an identification tag.
4. Either the soil is too acidic for these plants or there is not enough sunlight for them. If the soil is too acidic, then we will have to move the plants. We will also have to move the plants if there is not enough sunlight. So, it seems that we will definitely have to move the plants.
EXERCISES FOR PART THREE
I. What is wrong with the following statements?
1. Validity is when an argument is true; i.e., its premises are true and its conclusion is true.
2. An argument is valid when it is both sound and true.
3. Premises can be true or false; conclusions are sound or unsound.
4. An argument’s validity depends on the truth of its premises.
5. An argument’s soundness depends upon its form.
II. Determine whether the following statements are true or false, and why.
1. A valid argument can have false premises.
2. A sound argument can have a false conclusion.
3. If an argument is sound, then it must be valid.
4. All valid arguments are also sound arguments.
5. All sound arguments are also valid arguments.
6. If an argument has all true premises and a true conclusion, then it is sound.
7. A valid argument must have a true conclusion.
8. It is correct to say that an argument is true or false.
9. An invalid argument must have at least one false premise.
10. An invalid argument must have a false conclusion.
EXERCISES FOR PART FOUR
I. Find the valid forms:
1. If a then b
b
a
2. Not b
If a then b
Not a
3. a or b
If a then c
If b then d
If a then d
4. If a then b
If c then d
a or c
b or d
5. Not b
If b then a
Not a
6. If a then b
If c then d
If a then d
II. Symbolize the following arguments, putting them into standard form and determine whether they possess one of our five valid forms or our two formal fallacies. Watch for reversals of the “if-then” statement (e.g. a statement like “I will go if you go” needs to move the “if” part up front: “If you go then I will go” — “If y then i”; not “i if y.”)
1. Either my roommate is in the gym or she is in the cafeteria. But since you have found that she is not in the cafeteria, then she must be in the gym.
2. If everything we do is determined by forces in our environment then we never exercise free will. Thus, we never do exercise free will, because it has been proven that everything we do is determined by forces in our environment.
3. Entering this building is permitted if you have an identification tag. You are not permitted to enter this building, though, because you do not have an identification tag.
4. Either the soil is too acidic for these plants or there is not enough sunlight for them. If the soil is too acidic, then we will have to move the plants. We will also have to move the plants if there is not enough sunlight. So, it seems that we will definitely have to move the plants.
5. It says in the text that if sulfuric acid is too strong, then it will corrode the steel pipes. It will definitely not corrode our steel pipes, because I have determined that the acid is not too strong.
6. Gadgets flimp in cadence. But gadgets flimp in cadence if widgets will slurp obtrusively. Consequently, widgets will slurp obtrusively.
7. This drug is either a cure for cancer or it is a deadly poison. Consequently, it should be mass-produced or it should be destroyed. My reasoning for this is that it should be destroyed if it is a deadly poison, and that if it is a cure for cancer, then it should be mass-produced.
8. This rain is not caused by volcanic ash in the atmosphere. Thus this rain is caused by smog, because scientists have determined that this rain is caused either by volcanic ash in the atmosphere or by smog.
9. If the mind is the same as the brain, then the mind is material. It follows, then, that the mind is the same as the brain if the mind decomposes at death. This is because the mind will decompose at death if it is material.
5. It says in the text that if sulfuric acid is too strong, then it will corrode the steel pipes. It will definitely not corrode our steel pipes, because I have determined that the acid is not too strong.
6. Gadgets flimp in cadence. But gadgets flimp in cadence if widgets will slurp obtrusively. Consequently, widgets will slurp obtrusively.
7. This drug is either a cure for cancer or it is a deadly poison. Consequently, it should be mass-produced or it should be destroyed. My reasoning for this is that it should be destroyed if it is a deadly poison, and that if it is a cure for cancer, then it should be mass-produced.
8. This rain is not caused by volcanic ash in the atmosphere. Thus this rain is caused by smog, because scientists have determined that this rain is caused either by volcanic ash in the atmosphere or by smog.
9. If the mind is the same as the brain, then the mind is material. It follows, then, that the mind is the same as the brain if the mind decomposes at death. This is because the mind will decompose at death if it is material.
