LSAT Logical Reasoning - Medium Concepts

Front

What is the difference between a necessary assumption and a sufficient assumption?

Back

A **Sufficient Assumption** guarantees the conclusion is true (if true, conclusion must follow). A **Necessary Assumption** is required for the argument to hold (if negated, the argument fails). Sufficient assumptions are often 'stronger' or more absolute than necessary ones.

Front

Contrapositive

Back

A logically equivalent statement formed by negating and reversing a conditional statement. If the original is 'If A, then B' (A -> B), the contrapositive is 'If not B, then not A' (/B -> /A). The contrapositive has the same truth value as the original statement.

Front

Identify the flaw: 'Mistaking Necessary for Sufficient'

Back

To recognize or establish the identity of someone or something. From Latin idem meaning “the same,” via Late Latin identificare (“to make identical”), related to identitas (“identity”).

Front

What is the 'Main Point' or 'Main Conclusion' of an argument?

Back

The primary claim the author is trying to establish. It is often signaled by words like 'therefore,' 'thus,' 'hence,' or 'consequently.' Everything else in the passage serves as premises or background information to support this main point.

Front

Identify the flaw: 'Circular Reasoning'

Back

To recognize or establish the identity of someone or something. From Latin idem meaning “the same,” via Late Latin identificare (“to make identical”), related to identitas (“identity”).