If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

# Weaken | Video lesson

Watch one way to approach a question that asks you to identify a choice that weakens an argument on the logical reasoning section of the LSAT.

## Want to join the conversation?

• This question was just way too time consuming...
• why cant we go with choice A' why cant we say its not the road closure that caused the increase - its the migration ( By introducing a new sufficient element - we weakening the support - road closure as the cause) (if the migration came from inside the valley the conclusion of doubling the population is weakened as mentioned. Now even if the migration came from outside the valley it still wont strengthen the argument because the argument supposes that the increase clearly came from road closures and we are showing that its just a correlation not a causation)
• Although I initially though the same, re-watch the video and make note of the argument. Yes it would weaken the argument, but its not the strongest answer to weaken the argument - as the main answer we were looking for concerns weakening the correlation between the increase in the preserve population to the increase in the valley. If the valley population has stayed the same for the past 8 years, then it would weaken the author's argument (that due to the increase in the preserve population, the valley population will follow as such) as it shows that the bear population increase doesn't follow the same way.

Hope I could help, and if I explained it incorrectly, I hope someone can explain it correctly!
• When I read E, it says "has" and it seems like it is undermining the stimulus premise. Does anybody know how to not look at it this way on test day?
• A bit late, but the answer isn't A because we can't assume that the migration had nothing to do with the roads being closed. If the migration was due to the road being closed, that would strengthen the argument. All the migration choices require this sort of assumption. By contrast, E directly contradicts the conclusion, thereby weakening the argument. Be careful not to make any assumptions when reading these choices!
• Any help from the experts would be very helpful here.

At 9.18, Ma'am says that "even though bear population in the preserve doubled, the bear population in the valley remained the same. Therefore, this scenario shows that what worked for the preserve may not work for the valley."

I have a doubt because what information given in the option E is about the last 8 years whereas the conclusion talks about future. Why the idea of closing did not work for the whole valley in the past? Its because roads were not closed in the whole valley and were closed only in the preserve.

Therefore, in my opinion E can not be the correct answer.

Rather I believe that option A is the correct answer. Why do I believe so? Let's see here.

Author presents analogy in his or her argument. Roads were closed in the preserve for last 8 years and population of the bear got doubled. What is the analogy? If we close the road in the whole valley, the bear population in the whole valley will get doubled. So the author uses incidence of preserve as an evidence to make her claim.

Now let's evaluate option A.

Option A says that, in last 8 years, bear population in the preserve doubled because of migration. Do we know from where did those extra bear come? They may have come from the other parts of the valley or outside of the valley or the moon. Who knows? But question that from where these extra bear came doesn't matter because this option clear shows that the increase (doubled) in the bear population was not due to roads and was due to migration. Thereby, option A makes a big hole in the evidence presented by the argument.

So, why option A is not the correct choice?

Thank you.
(1 vote)
• Migration is not the cause of the population increase, but the way the change in population occurred. It could be the absence of the road that encouraged migration into the preserve. So A doesn't weaken the argument.