Logical Reasoning

PT102 · S2 · Q15 Some plants have extremely sensitive

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Some plants have extremely sensitive biological thermometers.

Conclusion (So)

If your thermometer shows 1°, and you're seeing uncurled rhododendron leaves as well as crocuses with mature but unopened blossoms, then you know that thermometer is accurate to within +/- 1 °.

Evidence

Once it's 2° or hotter, mature crocus blossoms are open. (if they're closed it's less than 2° C)

Once it's below 0°, leaves of rhododendrons curl up. (if they're uncurled, it's 0° or greater)

Evaluate

If we're seeing closed crocus we know it's less that 2°, and if we're seeing uncurled rhododendron leaves, we know it's 0° or greater.

So we know the only eligible temperature range is 0° ≤ x < 2°

If the thermometer measures 1° and has an accuracy reading within plus or minus 1°, then it could be as cool as 0° and as warm as 2°.

So ... this conclusion seems very valid.

Goal

We'd probably be pretty stumped. It seems like the math works and that saying .

But there must be some way to resist that conclusion. So let's look for some answer that would allow us to say that even though we're seeing uncurled leaves and unopened blossoms and a thermometer reading of 1°, it's still possible that the thermometer is more than 1° away from the real temperature.

15.

Which one of the following, if true, most seriously undermines the reasoning above?

  1. Neither rhododendrons nor crocuses bloom

    Out of Scope: rhododendron blossoms

    This answer seems to be trying to weaken by convincing us that someone would never simultaneously observe uncurled rhododendron leaves at the same time as unopened crocus blossoms. But ... 1) this conclusion is really hypothetical not literal. The author isn't saying someone will find themselves in this position. It's sort of implied that we're saying, "If you happened to see A and B with a thermometer that read 1° ..." 2) this isn't talking about uncurled rhododendron leaves. It's talking about the blossoms of rhododendrons, which wasn't a part of this argument. We have no idea what the temperature constraints are on the blossoms of a rhododendron.

    11% picked this

  2. Many people find it unpleasant

    Out of Scope: people's enjoyment

    This argument has nothing to do with whether a hypothetical person holding this 1° thermometer finds the outdoors pleasant or unpleasant. The author wasn't suggesting that we should all go do this experiment in 1° weather.

    0% picked this

  3. The climate and soil conditions

    No Impact

    If anything this feels like it strengthens the possibility that rhododendrons and crocuses could grow in the same place, but we don't actually care if they ever do. The author is speaking to a very hypothetical thought experiment where you happen to see a certain rhododendron stage and a certain crocus stage. He isn't promising that anyone will ever actually see this in real life.

    2% picked this

  4. Correct

    Air temperature surrounding rhododendrons, which

    Why this is right

    This allows us a way to argue that the conclusion could be wrong! Let's say temperature at ground level is actually 1.9°. Since the temp is more than 2 greater up 12 feet, that means the air temperature 12 feet up is over 3.9° C. The temperature 6 feet up, where our six foot scientist is holding her thermometer is 2.9° C. This would allow crocuses to be unopened (because it's less than 2° at ground level). And this would allow rhododendron leaves to be uncurled (since it's more than 0° twelve feet up where they live). But if the thermometer says 1° even though it's really 2.9°, then we've shown how the thermometer could be off by more than 1° C, even though we're seeing unopened crocus blossoms and uncurled rhododendron leaves. Is this answer insane? 100% certified crazy. They're talking about a temperature change of more than 2° C (which is like 5° F) between ground level and 12 feet up? I mean, yes, if you have a room with pitched ceilings and you climb up a 12 foot ladder, you will feel that it is at least 5° F warmer at the top of the ladder. But outdoors it's a little insane to think that air temperatures would vary that much. But that's not our job. The question system isn't saying, "Do you think this answer is true?" It's asking, "If you pretend this answer is true, would it allow you to weaken the argument?" And this is the only answer helping us to show how you could see uncurled leaves, unopened blossoms, and 1° on the thermometer, even though it's either under 0° or above 2° in reality.

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

    76% picked this

  5. Certain types of thermometers that

    Unclear Impact

    Is the hypothetical thermometer in our thought experiment one of these "certain types of thermometers"? We don't know, so this answer doesn't have any clear relevance.

    11% picked this

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