LSAT Logical Reasoning: Weaken Questions

A “weaken” question is one that asks you to identify a statement that, if true, would make a particular argument less believable. (These questions are also called “undermine questions.”) The question stem for a role of a statement question might read:

  • Which of the following, if true, would most weaken the argument?
  • The reasoning in the argument above is most undermined if which of the following is true?
  • Which of the following, if true, would most seriously weakens _____’s argument?

We solve these questions by following three steps:

  1. Identify the argument’s conclusion.
  2. Identify how the conclusion is supported.
  3. Choose the answer choice that makes the conclusion less believable.

Let’s take a look at each step.

Identify the Conclusion

The main conclusion of the argument is supported by everything else in the argument; it’s what the rest of the argument is attempting to convince you is true. If you struggle with identifying conclusions, take a look at the Identify the Conclusion Questions lesson.

Identify How the Conclusion is Supported

Make a note of the premises. What supports the conclusion? Why does the author think we should believe the conclusion? Silently paraphrase the support to yourself, trying to understand why the author finds the premises to be so convincing.

Choose the Answer

The correct answer will make the argument less believable. This usually is done by weakening the connection between the premises and the conclusion. If we cast doubt on our reasons for believing the conclusion, then we cast doubt on the conclusion as well.