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Topic: Logical
Reasoning
Strategy
Used: Denial Test
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One of the types of logical reasoning questions you'll see on
the LSAT is the assumption. An assumption bridges the gap between
an argument's evidence and conclusion. It's a piece of support
that isn't explicitly stated but that is required for the
conclusion to remain valid. When a question asks you to find an
author's assumption, it's asking you to find the statement
without which the argument falls apart.
In order to test whether a statement is necessarily assumed by
an author, we can employ the Denial Test. Simply deny or negate
the statement and see if the argument falls apart. If it does,
that choice is a necessary assumption. If, on the other hand, the
argument is unaffected, the choice is wrong.
Consider the following
example:
- Allyson plays volleyball for Central High School.
Therefore, Allyson must be over six feet tall.
You should recognize the second sentence as the conclusion and
the first sentence as the evidence for it. But is the argument
complete? Obviously not. The piece that's missing is the
assumption, and you could probably prephrase this one pretty
easily:
- All volleyball players for Central High School are over six
feet tall.
Now, let's use the Denial Test. What if it's not true that all
volleyball players for Central High School are over six feet
tall? Can we still logically conclude that Allyson must be taller
than six feet? No, we can't. Sure, it's possible that she is, but
it's also possible that she's not. By denying the statement, the
argument falls to pieces; it's simply no longer valid. And that's
our conclusive proof that the statement above is a necessary
assumption of this argument.
Other Strategy
Sessions: