Conditional Logic Made Easy – 4: The Communist Party

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! Now try these:

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About J.Y. Ping

J.Y. has been teaching the LSAT since 2006 and has taught thousands of students. He is the founder of 7Sage and PreProBono, two organizations dedicated to making legal education more accessible. He graduated from Columbia University in 2007 where he studied Economics, Political Science, and Philosophy and holds a J.D. from Harvard Law School.

J.Y. highly encourages all LSAT students to review their logic games using 7Sage's Fool Proof Method and to sign up for 7Sage's free trial LSAT course.