Logical Reasoning

PT2 · S2 · Q11 “If the forest continues to disappear

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“If the forest continues to disappear at its present pace, the koala will approach extinction,” said the biologist.

Biologist's Claim

If deforestation continues at its present pace, the koala will approach extinction. (If forest disappears, then koala extinct.)

Politician's Claim

So all that is needed to save the koala is to stop deforestation. (If deforestation stops, koala saved.)

Evaluate

The biologist gave a sufficient condition for extinction (continued deforestation). The politician treats stopping deforestation as sufficient to save the koala — but that flips the logic. Even if deforestation is the only thing now threatening the koala, stopping it does not guarantee survival; other forces (disease, predators, an existing low population) could still drive the koala extinct.

Goal

Find a scenario consistent with the biologist (deforestation stopped means the biologist's "if deforestation continues, koala extinct" trigger never fires — so the biologist's claim is not violated) but inconsistent with the politician (the koala dies anyway, despite deforestation stopping).

11.

Which one of the following statements is consistent with the biologist’s claim but not with the politician’s claim?

  1. Deforestation continues and the koala

    Both Agree

    If deforestation continues and the koala goes extinct, that is exactly what the biologist predicted — fully consistent with the biologist's claim. It is also consistent with the politician, because the politician's claim is conditional on stopping deforestation, and that did not happen here. We need a scenario that splits the two speakers.

    13% picked this

  2. Correct

    Deforestation is stopped and the

    Why this is right

    This splits them perfectly. Deforestation is stopped — meaning the biologist's "if deforestation continues" trigger never fires, so the biologist's claim is not violated. But the koala goes extinct anyway. That directly contradicts the politician, who said stopping deforestation is all that is needed to save the koala. The koala's extinction here proves there is some other threat the politician failed to consider — exactly the scope-shift gap the politician walked into.

    Skill tested: Must be False · how this choice captures the argument's function is the move to repeat next time.

    40% picked this

  3. Reforestation begins and the koala

    Both Agree

    Reforestation begins (which is more than just stopping deforestation) and the koala survives. The biologist's claim is not violated (deforestation did not continue). The politician's claim is also satisfied — stopping deforestation here led to the koala being saved. Both speakers are happy with this scenario; we need one that divides them.

    5% picked this

  4. Deforestation is slowed and the

    Both Agree

    Deforestation slowed (not continuing at the present pace) and the koala survived. This is consistent with both: the biologist's "continued deforestation" trigger did not fire, and the politician's claim — stopping is sufficient to save — is at least loosely supported by the survival outcome. Neither speaker is contradicted.

    32% picked this

  5. Deforestation is slowed and the

    Half Scope

    Deforestation slowed and the koala still approached extinction. The biologist talked about what happens if deforestation continues at its present pace — slowing it does not technically violate the prediction (we cannot tell what the biologist would say about a slower pace). But this scenario is not clean either: the politician spoke about stopping deforestation, and slowing is not stopping, so the politician's claim is not directly tested. Choice B is sharper because it actually shows the politician's exact scenario (deforestation stopping) failing.

    9% picked this

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