#20 - Amphibian populations are declining in numbers

[SeoYoung]

(a). It's a question about. Bible said in the commentary that not 'invariably choose' do not weaken the statement because the stimulus says 'consistently choose', so don’t you see 'consistently' as synonymous with 'always'? I use these two meanings interchangeably, so should we distinguish them in LSAT?

I’m sorry. Just distract this question.

[SeoYoung]

(D). It is a question about. I first think this answer choice as right answer since if the natural habitat of amphibians has not become smaller over the past century, the number of amphibians may not been declining so that the conclusion can be weakened. I wonder why this reasoning of mine is wrong. I have learned that we can weaken the stimulus by neglecting the premised used in the stimulus.

[Jeff Wren]

Hi Seo,

The stimulus states that "amphibian populations are declining in numbers worldwide." This is a premise and is not really in dispute. While it is possible to attack the premises, that isn't what happens in this question. Instead, you really want to focus on the conclusion.

The conclusion of the argument is that this population decline is caused by depletion of the ozone layer.

Answer D does not imply that "amphibian populations are not declining in numbers worldwide." You should read Answer D as stating that their habitats have not become smaller even though "amphibian populations are declining in numbers worldwide." In other words, Answer D is eliminating another alternate cause for why the amphibian populations are declining, which is one of the main ways of strengthening a causal argument.

It may be helpful to imagine that we wanted to Weaken this argument rather than Strengthen it. A great way to weaken the argument would be to show another reason/cause for why the amphibian populations are declining, such as showing that their habitat is being destroyed. If that were true, then the decline in the population may have nothing to do with the ozone layer. Of course, since this is a Strengthen question, you want to the opposite, such as ruling out other possible causes for the decline in population. This strengthens that the effect is in fact caused by the depletion of the ozone layer and not some other reason.