Logical Reasoning

PT117 · S2 · Q8 Most plants have developed chemical

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Most plants have developed chemical defenses against parasites.

Conclusion (Therefore)

The additional threat posed by synthetic pesticides sprayed on crop plants by humans is minimal.

Evidence

The average plant contains about 40 natural pesticides, that it has evolved as chemical defenses against parasites.

Humans ingest these natural pesticides without harm every day.

Evaluate

Given that ... humans ingest natural pesticides without harm every day,

How could we still argue that ... there is a significant additional threat posed by the synthetic pesticides that are sprayed on crop plants?

We would probably need some way to argue that what's true of natural pesticides isn't true of synthetic pesticides. Even though the natural ones are harmless, maybe the synthetic ones are harmful because they have different ingredients / potency / concentration?

We could also potentially argue that even though synthetic pesticides are relatively harmless as well, when you add synthetic pesticides atop natural pesticides the cumulative amount of poison is harmful (or maybe there's a harmful chemical reaction that occurs by adding synthetic pesticides on top of natural ones).

Goal

Look for four ways to argue that, .

8.

Each of the following, if true, weakens the argument EXCEPT:

  1. Humans have been consuming natural

    Weakens

    This points out a salient difference between natural and synthetic pesticides. While we've had thousands of years to evolve a tolerance for natural pesticides (rendering them essentially harmless when we consume them), we haven't evolved a tolerance for synthetic pesticides, which have only been around for a century or two (too fast for evolution).

    9% picked this

  2. The concentrations of natural pesticides

    Weakens

    This points out a salient difference between natural and synthetic pesticides that could allow us to argue that synthetic pesticides are more worrisome than natural ones are. Humans harmlessly ingest natural pesticides, because there are only trace amounts of natural pesticides on the food (let's say there's only 1mg of pesticide). Meanwhile, a thick layer of synthetic pesticides is sprayed on the food, so we might be consuming 20mg of synthetic pesticide and only 1mg of natural pesticide.

    2% picked this

  3. Natural plant pesticides are typically

    Weakens

    This points out a salient difference between natural and synthetic pesticides that could allow us to argue that synthetic pesticides are more worrisome than natural ones are. Synthetic pesticides have highly concentrated toxicity, whereas natural pesticides are usually less potent. (B) was saying, you're ingesting 1 mg of natural pesticide vs. 10 mg of synthetic. (C) is saying that a milligram of natural pesticide isn't as poisonous as is a milligram of synthetic pesticide.

    4% picked this

  4. Natural plant pesticides generally serve

    Weakens

    This points out a salient difference between natural and synthetic pesticides that could allow us to argue that synthetic pesticides are more worrisome than natural ones are. Humans harmlessly ingest natural pesticides, because those pesticides are evolved to hurt insects, not humans. Meanwhile, synthetic pesticides could be more worrisome for humans, because they're often harmful to a wider variety of organisms.

    6% picked this

  5. Correct

    The synthetic pesticides sprayed on

    Why this is right

    This actually strengthens the argument. Since this is an argument by comparison and the author is assuming, "if natural pesticides are harmless to humans, then synthetic pesticides will also be harmless to humans", we would weaken the argument by making natural and synthetic unfair to compare. We would strengthen the argument by making natural synthetic fair to compare. This answer makes them more comparable, saying that the synthetic pesticides work in essentially the same chemical fashion as the natural ones do. Thus, if our bodies can tolerate the chemistry of natural pesticides, it strengthens the author's claim that our bodies should be able to tolerate the similar chemistry of synthetic pesticides.

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

    80% picked this

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