eXERCISES STUDY 3: Syllogisms
Exercise 3.1 Definition Syllogisms
Fill in the blanks in each statement with the letter of the correct answer.
1. A _____ is an inference with two premises and three terms, each appearing twice but never twice in the same proposition.
2. The _____ is the predicate of the conclusion of a standard syllogism.
3. The _____ is the subject of the conclusion of a standard syllogism.
4. The term that occurs in both premises, but not in the conclusion is the _____ .
5. The _____ is the one that contains the major term.
6. The _____ is the one that contains the minor term.
7. The lower case letter "s" in the names of valid syllogism means _____ of the preceding form.
8. The lower case "p" in some of the names of valid syllogisms means _____ .
9. The _____ is the subject term of the major premise and the predicate term of the minor premise of a standard syllogism.
10. The _____ is the predicate of both premises of a standard syllogism.
11. The _____ is the subject of both premises of a standard syllogism.
12. The _____ is the predicate of the major premise and the subject term of the minor premise of a standard syllogism.
Fill in the blanks in each statement with the letter of the correct answer.
- a. conversion per accidens
- b. first figure
- c. major premise
- d. major term
- e. middle term
- f. minor premise
- g. minor term
- h. fourth figure
- i. second figure
- j. simple conversion
- k. standard syllogism
1. A _____ is an inference with two premises and three terms, each appearing twice but never twice in the same proposition.
2. The _____ is the predicate of the conclusion of a standard syllogism.
3. The _____ is the subject of the conclusion of a standard syllogism.
4. The term that occurs in both premises, but not in the conclusion is the _____ .
5. The _____ is the one that contains the major term.
6. The _____ is the one that contains the minor term.
7. The lower case letter "s" in the names of valid syllogism means _____ of the preceding form.
8. The lower case "p" in some of the names of valid syllogisms means _____ .
9. The _____ is the subject term of the major premise and the predicate term of the minor premise of a standard syllogism.
10. The _____ is the predicate of both premises of a standard syllogism.
11. The _____ is the subject of both premises of a standard syllogism.
12. The _____ is the predicate of the major premise and the subject term of the minor premise of a standard syllogism.
Exercise 3.2: Syllogisms
Determine the validity of each by comparison with the frame names of valid syllogisms or by means of the Five Rules. Use "V" for valid; "I" for invalid.
____1.
Some good Christians are communists because Some good Christians practice what they preach; and All communists practice what they preach.
____3.
Suppose someone argues: No logic students swallow propaganda.
The premises are:
____4.
All whom the Son makes free are free indeed, because all who know the truth are free indeed; and all whom the Son makes free know the truth.
____5.
____6.
____7.
____8.
____9.
Determine the validity of each by comparison with the frame names of valid syllogisms or by means of the Five Rules. Use "V" for valid; "I" for invalid.
____1.
- 1a. All thinking beings are existing beings.
- 1b. I am a thinking being
- 1c, .:. I am an existing being.
Some good Christians are communists because Some good Christians practice what they preach; and All communists practice what they preach.
____3.
Suppose someone argues: No logic students swallow propaganda.
The premises are:
- (1) No logic students are stupid; and
- (2) All stupid people swallow propaganda.
____4.
All whom the Son makes free are free indeed, because all who know the truth are free indeed; and all whom the Son makes free know the truth.
____5.
- 5a. Descriptive sciences have no place for evaluations.
- 5b. Psychology is a descriptive science, among others.
- 5c. Therefore, psychology has no place for evaluations.
____6.
- All that God does is good.
- God clearly predestinates evil.
- Therefore, God does good in predestinating evil.
____7.
- No person who knows the Truth is a slave of sin.
- All whom the Son makes free are persons who know the Truth.
- Therefore, no person whom the Son makes free is a slave of sin.
____8.
- Does it make sense to argue that some poor scholars are theologians
- because all theologians are former seminary students, and
- some seminary students were poor scholars?
____9.
- Our sense organs change either by reason of aging or by reason of disease leading to deception.
- These changes usually occur without our knowing it.
- Therefore, we are often or almost always deceived.
- Every system of philosophy must have a starting point, an axiom or set of axioms, for otherwise it could not start.
- Starting points cannot be demonstrated.
- Therefore, every system of thought must be based on an indemonstrable axiom.
Exercise 3.3: Deduction
Fill in the blanks in each statement with the letter of the correct answer.
1. _____ are never deduced because they are the starting points of all deduction.
2. _____ states: if in any valid mood its premise and conclusion be interchanged and contradicted, the result is a valid implication.
3. _____ states that if any valid implication, if its premise be strengthened or its conclusion weakened, a valid implication will result.
4. The premise of a valid implication is a _____ of its consequent and the conclusion is a _____ of its premise.
5. There are _____ by which any standard syllogism may be tested for validity.
6. One proves a _____ by applying rules to the axioms.
7. The five rules are _____ , if you can't do without them and there is at least one invalid syllogism to which the given rule alone applies.
Fill in the blanks in each statement with the letter of the correct answer.
- a. axioms
- b. theorem
- c. Rule I (Deduction)
- d. Rule II (Deduction)
- e. strengthened form
- f. weakened form
- g. Five Rules (validity of syllogisms)
- h. necessary & sufficient
1. _____ are never deduced because they are the starting points of all deduction.
2. _____ states: if in any valid mood its premise and conclusion be interchanged and contradicted, the result is a valid implication.
3. _____ states that if any valid implication, if its premise be strengthened or its conclusion weakened, a valid implication will result.
4. The premise of a valid implication is a _____ of its consequent and the conclusion is a _____ of its premise.
5. There are _____ by which any standard syllogism may be tested for validity.
6. One proves a _____ by applying rules to the axioms.
7. The five rules are _____ , if you can't do without them and there is at least one invalid syllogism to which the given rule alone applies.
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