Please don't forget the explanation to. Thanks
“If the forest continues to disappear at its present pace, the koala will approach extinction,” said the biologist.
“So all that is needed to save the koala is to stop deforestation,” said the politician.
Which one of the following statements is consistent with the biologist’s claim but not with the politician’s claim?
(A) Deforestation continues and the koala becomes extinct.
(B) Deforestation is stopped and the koala becomes extinct.
(C) Reforestation begins and the koala survives.
(D) Deforestation is slowed and the koala survives.
(E) Deforestation is slowed and the koala approaches extinction.
Notice that the politician’s statement is much stronger than the biologist’s. The biologist says merely
that if deforestation continues then the koala will approach extinction. This can be diagrammed as
where D stands for “deforestation continues” and E stands for “extinction.” In other words, ending
deforestation is a necessary condition for the koala’s survival. Now the politician says that if deforestation
stops then the koala will not approach extinction. This can be diagrammed as
This is stronger because it declares that ending deforestation is sufficient for the koala to survive. You
should notice this as the fallacy of denying the premise. Look at choice (B). It stops deforestation yet the
koala still becomes extinct. This is not consistent with the politician’s statement since he claimed stopping
deforestation would prevent the koala’s extinction. But (B) is consistent with the biologist’s claim since he
said only that if deforestation continued then the koala would become extinct. He said nothing about the
case in which deforestation stops—the koala could still become extinct for other reasons. Remember, if the
premise of an if-then statement is false, then we know nothing about the conclusion. The answer is (B).
"Appreciation is a wonderful thing. It makes what is excellent in others belong to us as well."
Press Kudos, if I have helped.