Logical Reasoning

PT109 · S3 · Q18 Studies have shown that photosynthesis

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Studies have shown that photosynthesis, the process by which plants manufacture life-sustaining proteins from sunlight and carbon, is actually intensified if the level of carbon dioxide in the atmosphere is increased.

Conclusion (it's obvious that)

Industrial activities are purely beneficial to agriculture and to those of us who depend on agriculture.

Evidence (since)

Industrial activity raises carbon dioxide levels. Higher carbon dioxide intensifies photosynthesis.

Evaluate

The evidence includes a little causal chain. more industry >> more CO2 >> more photosynthesis

The conclusion suddenly starts talking about agriculture, which means we have to make the common sense connection that agriculture is all about growing crops; crops are plants; plants do photosynthesis to live/grow/thrive.

So the intended causal chain is really industry >> more CO2 >> more photosynth >> more crops?

If we accept that industrial activities indirectly lead to more growth of crop plants, why would the conclusion be wrong to say that ?

Cuz it's hella extreme! Purely beneficial?

You mentioned one benefit that it has. Where did you get the idea that it only has benefits? Is it possible that industrial activities ever do something harmful?

My HEAVENS, yes it's possible!

Industrial activities often pollute the air / water, and the increase they've caused in CO2 is warming the planet to the point where over 50% of species have already gone extinct and many-many more are expected to follow (if we get to 75%, it qualifies as the Earth's sixth mass extinction).

How do we generalize the form of this flaw?

The author told us that X led to some benefit and then concluded that X is purely beneficial.

Goal

Let's look for an argument where it goes from explaining how X leads to some benefit to declaring that it is purely beneficial, failing to consider possible downsides.

18.

The flawed reasoning in the argument above is most similar to that in which one of the following?

  1. Because a high fiber diet

    Bad Conclusion Match

    This reasons that if some of a good thing is healthful, then all of it is even more healthful. This is still a flawed move, but it's different from saying "since X has a benefit, X is purely beneficial". This conclusion is claiming that one thing is superior to a second thing. The original conclusion was claiming that one thing has no downsides. A better conclusion would have said, "Thus, a high fiber diet is purely beneficial."

    14% picked this

  2. Correct

    Because exercise has been shown

    Why this is right

    We hear that something leads to a benefit: Exercise prevents diseases, injuries, and other ills. And then the author concludes that this thing is purely beneficial: No harm, and a lot of good, can come from exercise. That is the same leap from "does some good" to "does no harm," from the original argument. And just as it was easy to think of possible harms industrial activities could cause, it's easy to think of possible harms that exercise could cause.

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

    69% picked this

  3. Consistently consuming more calories than

    Bad Evidence Match

    This starts from something leading to a harm, not a benefit. excess calories cause weight gain We could probably still consider it the same flaw if it were to jump to a conclusion that said, thus consuming excess calories is purely harmful It wouldn't beat the correct answer as the closest match, but that would still be a close enough match to be a correct answer. However, the conclusion sounds nothing like that. It's advice, not an assessment of whether something is totally positive or totally negative.

    2% picked this

  4. It has been shown that

    Bad Conclusion Match

    We do have a premise that something (fresh fruits) leads to a benefit (more vitamins and minerals). But instead of concluding, "fresh fruits are purely beneficial", the conclusion here is a recommendation to abandon processed produce entirely, drawn from a comparative advantage.

    5% picked this

  5. Excessive use of penicillin tends

    Bad Evidence Match

    The evidence here is a harm, that overusing penicillin breeds resistance. So we'd have a pretty-good match if the conclusion said "Thus excessively using penicillin is purely harmful." But the conclusion is not about pure-good / pure-harm. It's a recommendation.

    10% picked this

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