Valid and Invalid Statement Recognition Mini-Drill

Each of the following problems presents a pair of arrow diagrams which
feature a statement and then an attempted inference. The attempted inference
is either a valid Repeat form or Contrapositive, or an invalid Mistaken
Reversal or Mistaken Negation. Identify the form of the attempted inference in
each problem. Answer on Page 123
1. Original statement: A----> B
Attempted Inference: B----> A
2. Original statement: C----> D
Attempted Inference: D----> C
3. Original statement: E----> F
Attempted Inference: E----> F
4. Original statement: G----> H
Attempted Inference: H----> G
5. Original statement: I----> J
Attempted Inference: I----> J
6. Original statement: K----> L
Attempted Inference: L----> K
7. Original statement: M----> N
Attempted Inference: M----> N
8. Original statement: O----> P
Attempted Inference: P----> O
Valid and Invalid Statement Recognition Mini-Drill Answer Key

1. Mistaken Reversal
Invalid. The A and B terms are reversed, but not negated. This is the
classic Mistaken Reversal form.
2. Contrapositive
Valid. The C and D terms are both reversed and negated, which is the
mark of the contrapositive.
3. Mistaken Negation
Invalid. The E and F terms are negated, but not reversed. This is the
classic Mistaken Negation form.
4. Contrapositive
Valid. The G and H terms are both reversed and negated. Compare this
problem to #2. Although the “slashes” are in different places, each is a
contrapositive because the terms are reversed and negated.
5. Repeat
Valid. The terms are simply repeated.
6. Mistaken Reversal
Invalid. Despite all the slashes, the only thing that occurs in this
problem is that the K and L terms are reversed.
7. Mistaken Negation
Invalid. The M and N terms are negated, but not reversed.
8. Contrapositive
Valid. Although this may look “upside down,” both terms are reversed
and negated. Compare this with the example at the top of page 121.
They are basically the same problem.