Q11 - If the forest continues...

[noah]

The key to this question is to see the difference between what the biologist and politician are stating.

The biologist states that if we continue to lose the forest, we'll lose the koalas. So, ~ F --> ~ K

The politician, who apparently wants to help, then states that "all that is needed" to save the koalas is to save the forest (to paraphrase). This is not the same thing that the biologist stated. The biologist would probably respond: "Well, you're right that we do need to save the forest to save the Koalas, but there are other factors -- we need folks to stop trapping them to use as guard koalas." The difference is that the politician has made saving the forest sufficient to save the koalas (meaning it's enough to do the job), while the biologist made it necessary (meaning, it's required, but is not definitely enough). So, the politician's statement could be translated to F --> K. This is not a proper inference from what the biologist stated. However, we're not asked to name the error, we're asked to find a situation that does not violate the biologist's claim, but does violate the politician's.

(B) does just that. If the forest survives, according to the politician, the koalas should as well. However, the biologist didn't rule out that possibility. He or she simply stated that saving the forest is a necessary component in saving the fuzzy beast, but not something that will ensure the koala's survival.

(A) is tempting, as it has the right pieces and seems to "fit" what folks are saying. However it doesn't violate either the politician's or the biologist's statement. Both would agree that if we lose the forest, we lose the koala.
(C) is incorrect because both people would agree that this is possible (though the politician, unlike the biologist, would think that the koala must survive in this scenario).
(D) may seem out of scope since it involves slowing the pace, but that does match up with the statements since they focus on whether deforestation will continue "at its present pace." The problem with (D) is that, like (C), both people would agree that this is possible, again with the politician thinking it's required.
(E) would be a better answer if it did not include "approach extinction." Approaching extinction is not the same as becoming extinct. We could interpret that phrase to mean that the koala does not become extinct, making it similar to (D).

#officialexplanation

[lisahollchang]

This is a tough one! Thanks for the explanation.

[Greatsk8erman]

I have a question Noah. Is this conditional reasoning or cause and effect reasoning? It appears to be cause and effect reasoning, which may be where I went wrong. I tried to take the contra positive of the biologist’s argument to attempt to infer something to help find the answer, but it seems to have taken me completely off track . Thanks

[noah]

As for taking the contrapositive of the biologist's statement, that's fine for finding an inference, but we're looking for something that does not violate the statement. So, for example, if a statement is A --> ~ B, and you're looking to write something that doesn't violate that, there are various possibilities:

A & ~ B,
~ A & B,

those are actually indicated by the statement in that A and B are sufficient to require ~ B and ~ A respectively.

However, this is also OK (in that it doesn't violate A --> ~ B):

~ A & ~ B.

It's OK because there's nothing saying what must occur if you have either of those terms.

So, the point is, there's a difference between finding an inference and finding something that doesn't violate a rule. Make sense?

[Greatsk8erman]

I think I concentrated on the "present pace" too much and tried to find an answer that agreed, and the more that I look at it, B does agree with it. I just really think this was a tough one for me; I had to diagram it out real quick and see the difference in statements in diagram form to really conceptualize it (I’m an engineering student lol). Thanks for your explanation!

[zee.brad]

I think I concentrated on the "present pace" too much and tried to find an answer that agreed, and the more that I look at it, B does agree with it. I just really think this was a tough one for me; I had to diagram it out real quick and see the difference in statements in diagram form to really conceptualize it (I’m an engineering student lol). Thanks for your explanation!

Me too! I was totally fall for "present pace", so for me, the difference between bio and politician is "present pace" and "totally stop", so I chose D since it agreed with bio, but not exactly agree with politician.....

[randitect]

Two questions:

First, what is the answer to Noah's challenge, beginning with : "The koalas survives..." ? Tried, but am at a loss...

Second, every time I try writing the politician's claim, I wind up with: koala ---> forest (or stop deforestation). The "needed" is throwing me off, for I keep recording stop deforestation (all that is needed) as the required condition for saving the koala. How can I think about this the correct way?

Thank you.

I like any question that involves koalas -- they're apparently so high from eucalyptus that they sometimes fall out of trees and continue to sleep after hitting the ground.

Anyway, the key to this question is to see the difference between what the biologist and politician are stating.

The biologist states that if we continue to lose the forest, we'll lose the koalas. So, ~ F --> ~ K

The politicians, who apparently wants to help, then states that "all that is needed" to save the koalas is to save the forest (to paraphrase). This is not the same thing that the biologist stated. The biologist would probably respond: "Well, you're right that we do need to save the forest to save the Koalas, but there are other factors -- we need folks to stop trapping them to use as guard koalas." The difference is that the politician has made saving the forest sufficient to save the koalas (meaning it's enough to do the job), while the biologist made it necessary (meaning, it's required, but is not definitely enough). So, the politician's statement could be translated to F --> K. This is not a proper inference from what the biologist stated. However, we're not asked to name the error, we're asked to find a situation that does not violate the biologist's claim, but does violate the politician's.

(B) does just that. If the forest survives, according to the politician, the koalas should as well. However, the biologist didn't rule out that possibility. He or she simply stated that saving the forest is a necessary component in saving the fuzzy beast, but not something that will ensure the koala's survival.

(A) is tempting, as it has the right pieces and seems to "fit" what folks are saying. However it doesn't violate either the politician's or the biologist's statement. Both would agree that if we lose the forest, we lose the koala.
(C) is incorrect because both people would agree that this is possible (though the politician, unlike the biologist, would think that the koala must survive in this scenario).
(D) may seem out of scope since it involves slowing the pace, but that does match up with the statements since they focus on whether deforestation will continue "at it's present pace." The problem with (D) is that, like (C), both people would agree that this is possible, again with the politician thinking it's required.
(E) would be a better answer if it did not include "approach extinction." Approaching extinction is not the same as becoming extinct. We could interpret that phrase to mean that the koala does not become extinct, making it similar to (D).

If you want a challenge, try writing another correct answer choice that starts with "The koalas survives..." Post it here if you figure it out.

[noah]

Two questions:

First, what is the answer to Noah's challenge, beginning with : "The koalas survives..." ? Tried, but am at a loss...

Second, every time I try writing the politician's claim, I wind up with: koala ---> forest (or stop deforestation). The "needed" is throwing me off, for I keep recording stop deforestation (all that is needed) as the required condition for saving the koala. How can I think about this the correct way?

Thank you.

For the first one, cough-cough, I don't think there is an answer to my "challenge." It was, ahem, an ancient challenge meant to hone your powers. Well done, Grasshopper.

As for the second, you're bumping up against the value of just using key words for decoding. Think of it this way: does the politician that stopping deforestation is the only way? Does it have to be that way? No, it's all that is needed. The politician's statement doesn't contradict the idea that maybe there's some zoo breeding program that would also work.

Try translating this one: All you have to do to make a good pie is buy one at the store, peel off the label, heat, and serve!

highlight for answer: buy pie... --> good pie

Even though there's a "have to" it doesn't indicate the necessary condition.

[kumsayuya]

115.
• Forest continues to disappear at this rate -- koala approaches extinction
• Stop forestation - koala is saved

First of all – the issue with the politicians argument is that it takes the stopping of forestation to be SUFFICIENT for stopping koala extinction – but this is not what the biologist is saying. The biologist is stating ONE sufficient condition for the koala to approach extinction.

A. I think that this is actually consistent with the biologist’s view point, and we are looking for something that is NOT. For example, he said that stopping forestation is sufficient to save them – but if it continues and they become extinct, it seems to be consistent with the idea that if they would have stopped, presumably the koalas could have been saved

B. This is the direct counter to the politician – its stopped, (his sufficient condition) and the effect still occurs, meaning that he is wrong in thinking that stopping deforestation is sufficient to save koalas. Its also consistent with the biologist because this doesn’t contradict what was stated – if deforestation continues, they will approach extinction – this can still very much be true, even if deforestation is stopped, and the koala is still becoming extinct

C. Seems consistent with the biologists point !

D.I think that this is, in the end, still consistent with the biologists point. He says if it stopped, it will save them. This isn’t contradicted by the idea that deforestation is slowed (not necessarily stopped), and the koalas survived. The politician thinks it sufficient to stop it, but that doesn’t mean that other things couldn’t stop it too – such as deforestation being slowed.

E. Similarly to (D) – its not contradicting the politicians claim – he says, we stop deforestation, koalas will be safe – but what if deforestation is SLOWED and they approach extinction? All this does is allow the politician to say “I told you so” because he would have said, if you STOPPED it, instead of slowed it, then we wouldn't have a bunch of dead koalas right now

[logicfiend]

Having read these responses (thanks for the great explanations, guys!), what I realize this question is really asking is for us to essentially negate the politician's statement, and we see that it is still consistent with the biologists' statement.

I too had trouble translating the politician's statement into logic, but it comes to Deforestation stopped --> Koala survives.

Therefore, to negate it, we would have to negate the necessary condition.

Deforestation stopped --> Koala DOES NOT survive, which is B.

It's all in the logic!

[sarah_sarah99]

Two questions:

First, what is the answer to Noah's challenge, beginning with : "The koalas survives..." ? Tried, but am at a loss...

Second, every time I try writing the politician's claim, I wind up with: koala ---> forest (or stop deforestation). The "needed" is throwing me off, for I keep recording stop deforestation (all that is needed) as the required condition for saving the koala. How can I think about this the correct way?

Thank you.

For the first one, cough-cough, I don't think there is an answer to my "challenge." It was, ahem, an ancient challenge meant to hone your powers. Well done, Grasshopper.

As for the second, you're bumping up against the value of just using key words for decoding. Think of it this way: does the politician that stopping deforestation is the only way? Does it have to be that way? No, it's all that is needed. The politician's statement doesn't contradict the idea that maybe there's some zoo breeding program that would also work.

Try translating this one: All you have to do to make a good pie is buy one at the store, peel off the label, heat, and serve!

highlight for answer: buy pie... --> good pie

Even though there's a "have to" it doesn't indicate the necessary condition.

Exactly what I was looking for, thanks!

[DavidP715]

Biologist: If the forest continues to disappear at its current pace, the koala will approach extinction.

Similar if-then statement: If the lawnmower starts, then the key must be in the ignition.

The key MUST be in the ignition for the lawnmower to start. The lawnmower CANT start without that although it may need more things like gas, etc. essentially what a necessary statement is.

For the biologist statement, Koalas MUST approach extinction for deforestation to continue at its current pace. Does that follow logically? I feel as if that doesn't make any sense whatsoever but im trying to follow logically.

I understand that the Biologist statement, taking from the contrapositive, basically means

The forest NOT disappearing at its current pace is necessary for koalas NOT becoming extinct. Which allows deforestation to STOP and koalas to still become extinct because the necessary condition can be met and still not result koalas not becoming extinct, just like a lawnmower not starting even tho the key is in the ignition.

Please someone correct what i have underlined i simply can't wrap my head around it and its ESSENTIAL to understand for this test! Thanks!

[ohthatpatrick]

Conditional logic represents certainty, usually certainty that comes from one of these four sources:
1. a rule / condition / stipulation
2. a universal
3. a guarantee
4. a requirement

If we write a conditional
A --> B

we can choose to read that as
1. When A occurs, we're instructed to do/believe B.
2. All A's are B.
3. Whenever A happens, it guarantees that B also happens.
4. In order for A to happen, it must be that B happens / has happened. (A requires B to happen)

I think you're just confusing yourself by taking ONE POTENTIAL way of talking about conditional logic (B is necessary to A) and forcing it on contexts that make it sound lame.

RULE: If you pass GO, collect $200
sounds weird to formulate that as a necessary condition "Collecting $200 is required of passing GO"

UNIVERSAL: All the basketball players are wearing tank tops.
sounds weird to say "Wearing a tank top is required of being one of the basketball players".

GUARANTEE: Jumping off this building will kill you.
sounds weird to say "Being killed is required of jumping off this building"

You should choose whichever language from that 1 / 2 / 3 / 4 seems to most comfortably fit the given context.

For the koala thing, I would never see that original claim as a statement of a requirement. It sounds more like a guarantee to me. So I'd phrase it as "if the forest keeps disappearing, that guarantees that koalas will be pushed to the brink of extinction".

Since your other example said " .... the keys MUST be in the ignition", it reads more like a requirement. So it's natural to phrase it as "having keys in the ignition is required in order to start the car".

Hope this helps

[DavidP715]

Yep, makes a lot more sense. I feel as if i wanted to believe it was a necessary requirement when in reality it's more like a necessary RESULT.