This question type demands that you find a new piece of information that, if true and/or added to the existing argument, will make the conclusion less likely to be true.
Most Weaken question stems contain either the word “weaken” or a synonym of it. You will also typically see phrases like “if true”, “calls into question”, “seriously undermines” and “casts the most serious doubt on” in the Weaken question stems.
Let’s have a look at an example:
Archaeologist: Researchers excavating a burial site in Cyprus found a feline skeleton lying near a human skeleton. Both skeletons were in the same sediment at the same depth and equally well-preserved, suggesting that the feline and human were buried together about 9,500 years ago. This shows that felines were domesticated around the time farming began, when they would have been useful in protecting stores of grain from mice.
Which of the following, if true, would most seriously weaken the archaeologist’s argument?
(A) Archaeologists have not found any remains of stores of grain in the immediate vicinity of the burial site.
(B) The burial site in Cyprus is substantially older than any other known burial site in which a feline skeleton and a human skeleton appear to have been buried together.
(C) Paintings found near the burial site seem to show people keeping felines as domestic companions, but do not show felines hunting mice.
(D) In Cyprus, there are many burial sites dating from around 9,500 years ago in which the remains of wild animals appear to have been buried alongside human remains.
(E) Before felines were domesticated, early farmers had no effective way to protect stores of grain from mice.
Breaking it down:
Conclusion: “This shows that felines were domesticated around the time farming began, when they would have been useful in protecting stores of grain from mice.”
Supporting Evidence: “Researchers excavating a burial site in Cyprus found a feline skeleton lying near a human skeleton. Both skeletons were in the same sediment at the same depth and equally well-preserved, suggesting that the feline and human were buried together about 9,500 years ago.”
Any evidence that goes against the assumption (that farming began in Cyprus 9,500 years ago) should weaken the argument. Bear in mind though, that there are other ways of weakening the argument. Because the argument lays some emphasis on the domestication of felines, any evidence that shows us that the domestication happened much earlier than 9,500 years ago, or that the two skeletons were not actually buried together back then, would also weaken the argument.
Option A attempts to attack the assumption directly, but the absence of a grain store near the burial site cannot decisively point towards the fact that farming did not exist 9,500 years ago. Option B comes close to making a weakening point when it touches upon the fact that the argument does not give us much information about other burial sites; something that could’ve helped mark just how old the burial really was. Option C does raise a question on the purpose behind the domestication as being related to farming, but fails to attack the author’s conclusion that the domestication still happened, and that it started around the same time as the farming. If, according to option D, there do exist other burial sites carrying the remains of other wild animals alongside human remains, then the argument revolving around the domestication of cats for hunting purposes falls apart. Option E strengthens the argument, rather than weakening it, because it gives more reason to early farmers to domesticate local cats.
Answer is option D.