#11 - If the forest continues to disappear at its present

[David Boyle]

Hi Powerscore!
Just wondering how does (B) fit into the description that "consistent with the biologist's claim but not with the politician's claim".
Thanks!

Hello GLMDYP,

There could be other things, for the biologist, that could hurt the koala. The biologist just says that deforestation will hurt, but other things could hurt too, for all we know. But for the politician, **all that's needed** to save the koala is stopping deforestation. So (B) is consistent with both claims.

David

[GLMDYP]

Crispy and clear! Thanks!

[David Boyle]

Hi Powerscore!
Just wondering how does (B) fit into the description that "consistent with the biologist's claim but not with the politician's claim".
Thanks!

Hello GLMDYP,

There could be other things, for the biologist, that could hurt the koala. The biologist just says that deforestation will hurt, but other things could hurt too, for all we know. But for the politician, **all that's needed** to save the koala is stopping deforestation. So (B) is consistent with both claims.

David

Looking back, I actually should have concluded, "So (B) is consistent with only one claim, not both claims." Not sure how I flipped things around there, when all my reasoning above pointed in the correct direction. :P Thanks!

[GLMDYP]

Thank you Dave and David! You guys are awesome!!

[Johnclem]

Hi powerscore,

I did this question over and over again. And read the explanations. I really can't figure out what I'm doing wrong. Here is my thought process . Also I had trouble getting rid of A and D.


BIOLOGIST: if the forest disappears ---> Koalas approach extinction .

POLITICIAN : if the forest doesn't disappear ---> koalas don't get extinct
Contrapositive: koalas get extinct ----> forest disappears

Analysis :
So I see the flaw is that the biologist makes the disappearing of the forest a sufficient condition , whereas the politician makes it a necessary condition. And our task is to find an answer that contradicts the politicians statement.


A) why is this wrong ? This statement is in agreement with the biologist and in a disagreement with the politician. forest disappears --> kola becomes extinct

B) correct : this answer choice could be true for the biologists and cannot be for the politician .

C) wrong: this could be true for both

D) why is this wrong ? Isn't this choice contradicting the politicians statement whom believes that it's necessary to stop deforestation ? Doesn't This choice imply an alternate sufficient? (slowed ---> koala survives. )

E)wrong : because it contradicts the biologist.


Thanks
-John

[Nikki Siclunov]

Hi John,

Thanks for your question. We have two points of view on the issue of deforestation and its effect on the well-being of the koala. Your understanding of both viewpoints is correct:

• Biologist: Forest disappears Koala approaches extinction
  Politician: Forest does NOT disappear Koala does NOT become extinct

It is imperative to understand the nature of the task at hand. The correct answer choice must contradict the politician's claim, but not the biologist's. This is precisely what (B) does: deforestation is stopped, and the koala still becomes extinct. This goes against the politician's claim, according to which stopping deforestation should be sufficient to save the koala. This claim is also consistent with the biologist's claim, who never promised that stopping deforestation would be enough to save the koala. Thus, answer choice (B) is correct.

Answer choice (A) is consistent with both claims. The politician argues that stopping deforestation would be enough to save the koala. So, is it possible that deforestation continues and the koala becomes extinct? Of course! This claim does not contradict either speaker.

Answer choice (C) is also consistent with the politician's claim, because it would be reasonable to assume that if "reforestation" occurs, then deforestation has indeed stopped.

Answer choices (D) and (E) propose outcomes when deforestation is "slowed." According to the politician, survival is guaranteed if deforestation is stopped, but if it's slowed down - who knows? Neither answer choice contradicts his position. Once again, the politician does not believe that stopping deforestation is necessary to save the koala. Rather, it is sufficient for saving it (stopping deforestation is all we need to do to save the koala).

Hope this clears it up!

[biskam]

Hi John,

Thanks for your question. We have two points of view on the issue of deforestation and its effect on the well-being of the koala. Your understanding of both viewpoints is correct:

• Biologist: Forest disappears Koala approaches extinction
  Politician: Forest does NOT disappear Koala does NOT become extinct

It is imperative to understand the nature of the task at hand. The correct answer choice must contradict the politician's claim, but not the biologist's. This is precisely what (B) does: deforestation is stopped, and the koala still becomes extinct. This goes against the politician's claim, according to which stopping deforestation should be sufficient to save the koala. This claim is also consistent with the biologist's claim, who never promised that stopping deforestation would be enough to save the koala. Thus, answer choice (B) is correct.

Answer choice (A) is consistent with both claims. The politician argues that stopping deforestation would be enough to save the koala. So, is it possible that deforestation continues and the koala becomes extinct? Of course! This claim does not contradict either speaker.

Answer choice (C) is also consistent with the politician's claim, because it would be reasonable to assume that if "reforestation" occurs, then deforestation has indeed stopped.

Answer choices (D) and (E) propose outcomes when deforestation is "slowed." According to the politician, survival is guaranteed if deforestation is stopped, but if it's slowed down - who knows? Neither answer choice contradicts his position. Once again, the politician does not believe that stopping deforestation is necessary to save the koala. Rather, it is sufficient for saving it (stopping deforestation is all we need to do to save the koala).

Hope this clears it up!

When I wrote out the conditional statement for the politician I did a mistaken reversal...
In my head when i read "So all that is needed to save the koala is to stop deforestation"...
I said... "to save the koala" (suff), what we need to do is "stop deforestation" (necessary)
so: if the koala does not approach extinction ---> then deforestation does not continue at the present rate

Now that I know I did a mistaken reversal, I know the correct answer is:
If the deforestation does not continue at the present rate --> then the koala does not approach extinction

The issue is my mind doesn't naturally think of the original statement in such terms so I'm hoping someone could explain why my mistaken reversal is wrong and how I was correctly supposed to read the statement.

Thank you!

[Eric Ockert]

The phrase "all that is needed" is a tricky one. It includes a sufficient term, "all", as well as a necessary term, "needed." But if you take a step back and think about what that phrase really means, it really equates to "enough" or "sufficient. The other trick is that phrase is modifying "stop deforestation" NOT "save the koala." So here:

"All that is needed to save the koala is to stop deforestation"

is like saying:

"Stopping deforestation is sufficient to save the koala."

So that rule would be diagrammed:

Stop deforestation Save Koala

Your final diagram would be another correct way to diagram the rule.

What probably happened here is that you locked in on the "needed" language and used it alone to modify "stop deforestation." That would create the Mistaken Reversal you ultimately ended up with.

Hope that helps!

[bella243]

What is this question called? Must be true?

[Adam Tyson]

We classified it as a Must Be True, Bella, but it's also kind of a hybrid question in that we are looking for something that is consistent with one statement (that's a Must Be True idea) and is, at the same time, inconsistent with another statement (that is a Cannot Be True idea). So it's actually both a Must Be True and a Cannot Be True at the same time! This question was from October 1991, and we haven't seen too many like it since. Weird and fun!

When I first read the stimulus I expected a Flaw in the Reasoning question, because the politician definitely misunderstood the claim made by the biologist and turned an ordinary conditional claim into a biconditional. I was a little surprised at the stem, but once you know what the politician did wrong it's not a big step to finding something that shows that error.