Logical Reasoning

PT140 · S1 · Q5 Essayist: If Earth's population

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Essayist: If Earth's population continues to grow geometrically, then in a few centuries there will be ten people for every square meter (approximately one person per square foot) of Earth's surface.

Conclusion

This would be a temporary solution at best. (i.e. colonizing other planets would only temporarily solve the problem of overpopulation on Earth)

Evidence

Suppose the population is doubling every 30 years -- in the year 2500, half of Earth's population could emigrate to Mars, and you'd be right back to being just as crowded as you were on Earth by 2530.

Evaluate

When we're doing Main Conclusion questions, we read the paragraph expecting that most of the time the Conclusion will appear earlier than the Evidence.

In particular, we look out for the two most common patterns: - the Conclusion appears after a pivot word like "but, yet, however" - the Conclusion is the first sentence

The first sentence of this paragraph is a mathematical fact. Facts aren't conclusions. Opinions are (supported Opinions, to be specific).

When the second sentence begins "some people have claimed ... ", we anticipate the classic form of a rebuttal argument:

Some people say X. But / yet / however, they're wrong. Here's why.

The third sentence begins with the "however" pivot we were anticipating. The author says that the solution these 'some people' are peddling is a temporary one, because if we're doubling ever 30 years, then losing half the population only solves the problem for 30 years.

Goal

Look for an answer that sounds like the first clause of the final sentence: .

5.

Which one of the following most accurately expresses the conclusion drawn in the essayist's argument?

  1. If Earth's population continues to

    Background

    This is just a factual, mathematical claim. It isn't supported by any reasons. Supporting reasons for this claim would sound mathematical: why would the density be 10 people / sq. meter in this hypothetical? because ... there are currently 8 billion people at a growth rate of 10% per year. The habitable land mass of Earth is 20 billion square meters. (etc.)

    3% picked this

  2. Due to the continuing geometric

    Unstated

    We're not trying to draw an Inference or call out an unstated Assumption on Main Conclusion. We're trying to point at the explicit claim that is the author's conclusion and then find an answer that matches. This answer choice was never stated.

    12% picked this

  3. If Earth's population continues to

    Last Idea Trap

    The conclusion is the last claim in the paragraph only like 10% of the time on Main Conclusion questions, so be very suspicious any time you're picking an answer that says the last idea. This is a premise, supporting our actual conclusion. There isn't any supporting reason offered for this claim. It's self-justifying math to say that, "If X doubles every 2 hours, then if you cut X in half, you'll be back to the original amount 2 hours later."

    11% picked this

  4. The population of Earth's surface

    Unstated

    We're not trying to draw an Inference or call out an unstated Assumption on Main Conclusion. We're trying to point at the explicit claim that is the author's conclusion and then find an answer that matches. The idea in this answer choice was never stated.

    16% picked this

  5. Correct

    Learning how to colonize other

    Why this is right

    This is the author's opinion, rebutting the "some people" in the previous claim. Support is indicated by the colon, ":" and if we were to ask, "why should we believe that it will be a temporary solution at best?", the final idea would sound like an answer -- "because if the population is doubling every 30 years, then shipping off half the population to another planet only buys you 30 years before you're right back where you started".

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

    58% picked this

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