[This is a lesson excerpt from our online course, for which we invite you to enroll.]
Group 4 is made up of the following terms:
- No
- None
- Not both
- Never
- Cannot
All the words in this group follow this translation rule:
You pick either idea, then negate that idea, then make the idea you negated the necessary condition.
Let’s try it, in six simple steps:
None of the Americans attended the dictators’ party.
Step 1 - Identify the logical operator
Here, it’s “none.”
Step 2 - Identify the two main concepts (or groups, categories, events or ideas)
Here, it’s the two events “being an American” and “attending the dictator’s party.”
Step 3 - Assign symbols to the two main concepts
Here, “A” for “being an American” and “ADP” for “attending the dictator’s party.”
Step 4 - Apply the translation rule
Here, pick an idea “A”, negate it to “/A”, and make "/A" the necessary condition.
ADP –> /A
Step 5 - Find the contrapositive
A –> /ADP
Step 6 - Translate back to English
If you’re an American, then you did not attend the dictator’s party.
Just like that!
(Photo credit: purpleslog - http://www.flickr.com/photos/purpleslog/)