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Philosophy 103: Introduction to Logic
Exercises on Successive Immediate Inferences
Abstract: The
following exercises are taken from Irving M. Copi and Carl Cohen, Introduction to Logic,
10th edition (Upper Saddle River, NJ: Prentice Hall, 1998), 238-239, IV: 1-10. |
Please note: The use of
"S" and "P" in these problems represents the terms
"socialists" and "pacificists" respectively. "S" and
"P" do not represent the subject and predicate positions--the
subject and predicate positions cannot, of course, be moved and still make sense as an
English sentence. If you have any difficulty in solving these
exercises, study carefully these strategies. |
|
|
Statement |
|
Reason |
|
Truth
Value |
1 |
1. All S is P. |
given |
true |
|
2. All nonP is nonS. |
contraposition |
true |
3. Some nonP is not
nonS. |
contradiction |
false |
|
2 |
1. All S is P. |
|
given |
|
true |
|
2. No S is nonP. |
obversion |
|
true |
|
3 |
1. All S is P. |
|
given |
|
true |
|
2. All nonP is nonS. |
contraposition |
true |
3. All nonS is nonP. |
conversion |
undetermined |
|
4 |
1. All S is P. |
|
given |
|
true |
|
2. No S is nonP. |
obversion |
true |
3. No nonP is S. |
conversion |
true |
|
5 |
1. All S is P. |
|
given |
|
true |
|
2. All nonP is nonS.*
NOTE |
contraposition |
true |
3. No nonP is nonS. |
contrariety |
false |
4. No nonS is nonP. |
conversion |
false |
|
6 |
1. All S is P. |
|
given |
|
true |
|
2. All nonP is nonS. |
|
contraposition |
|
true |
|
7 |
1. All S is P. |
|
given |
|
true |
|
2. No S is P.*
NOTE |
contrary |
false |
3. No P is S. |
conversion |
false |
4. All P is nonS. |
obversion |
false |
5. No P is nonS. |
contrariety |
undetermined |
|
8 |
1. All S is P. |
|
given |
|
true |
|
2. Some S is not P. |
contradiction |
false |
|
9 |
1. All S is P. |
|
given |
|
true |
|
2. All P is S. |
conversion |
undetermined |
|
10 |
1. All S is P. |
|
given |
|
true |
|
2. No S is nonP |
obversion |
true |
3. No nonP is S. |
conversion |
true |
4. Some nonP is S. |
contradiction |
false |
After studying these inferences, try the quiz on Successive
Immediate Inferences.
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