Chapter 9: CATEGORICAL SYLLOGISMS - Practice on Rules -

Multiple Choice:
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No. of Questions= 21

In this exercise, you will be given a categorical syllogism, and asked to determine whether it is valid or invalid using the rules of validity.

To determine validity, you must use the method of rules.

Rules of Validity

In order to be valid, a categorical syllogism must satisfy all four of the following rules; if it violates one or more, it is invalid.

1) The middle term must be distributed in at least one premise.
2) If a term is distributed in the conclusion, it must be distributed in the premise in which it occurs.
3) The premises cannot both be negative.
4) If one premise is negative, the conclusion must be negative; if the conclusion is negative, one premise must be negative.

 1. All M is PNo S are MTherefore, No S is PThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 2. Some M are not PAll M are STherefore, some S are not PThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 3. All P are MAll M are SAll S are PThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 4. All Q is NSome M is QTherefore, some M is NThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 5. No A are DSome A are BTherefore, some B are not DThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 6. All B are DNo C are BTherefore, No C are DThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 7. All M are NSome P are not MTherefore, some P are not NThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 8. No B are DAll A are DTherefore, no A are BThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 9. All W are YNo X are WTherefore, some X are not YThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 10. All D are BSome D are ATherefore, some A are BThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 11. All B are ASome C are not ATherefore, some C are not BThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 12. All N are PSome P are MTherefore, some M are NThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 13. All N are PSome P are MTherefore, some M are NThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 14. No A are BSome C are ATherefore, some C are BThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 15. Some D are AAll C are ATherefore, some C are DThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 16. No B are DSome D are ATherefore, some A are not BThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 17. Some Q are MNo M are PTherefore, some P is not QThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 18. No B are DSome A are DTherefore, some A are BThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 19. All W are YSome W are XTherefore, all X are YThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 20. All D are CSome D are BTherefore, some B are CThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative. 21. Some A are not BNo A is CTherefore, some C are not BThis syllogism is: a) Valid. b) Invalid: the middle term is not distributed in at least one premise. c) Invalid: a term is distributed in the conclusion, but is not distributed in the premise in which it occurs. d) Invalid: the premises are both negative. e) Invalid: one premise is negative, but the conclusion isn't negative, or the conclusion is negative, but one premise isn't negative.

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