Logical Reasoning

PT138 · S3 · Q9 All laundry detergents

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All laundry detergents contain surfactants, which can harm aquatic life.

Conclusion (Therefore)

There's no reason to suppose that "eco-friendly" laundry detergents are less damaging to the environment than other laundry detergents are.

Evidence

All detergents have surfactants, which can harm aquatic life.

And the environmental effects of most other ingredients in eco-friendly detergents are unknown.

Evaluate

Given that ... the environmental effects of most ingredients in eco-friendly detergents are unknown,

How could we argue that ... There is some reason to think that eco-friendly detergents are less damaging to the environment than other detergents?

Maybe the environmental effects of these eco-friendly detergents haven't been tested yet, but we know from the list of the ingredients that none of the ingredients involved are known to have bad environmental effects.

Maybe there is an ingredient in normal detergents that we know is very damaging, so knowing that ingredient is absent in eco-friendly detergents would itself be "a reason to suppose" that the latter is less damaging to the environment.

Goal

We wouldn't be able to convince anyone for certain that eco-friendly detergents are less damaging, since the data isn't in. It's unknown.

But the author is going one step further by saying, . We might not know for sure whether the mRNA vaccines for COVID are going to have bad long-term effects, but we can still have reason to suppose that they will not (such as the fact that mRNA technology has been used in cancer therapies for years with no ill effects).

Let's look for an answer that allows us way to say, .

9.

Which one of the following, if true, most weakens the argument?

  1. Correct

    Laundry detergents that are advertised

    Why this is right

    Does this help us argue, "We have some grounds for hoping that eco-friendly detergents are less damaging"? Sure! We know surfactants can be harmful, so if eco-friendly detergents have less of that harmful stuff, then there is reason to suppose that they are less harmful to the environment.

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

    84% picked this

  2. There is no reason to

    Strengthens, if anything

    One of our possible objections was arguing, "Sure, we don't know what harm the other ingredients in eco-friendly detergents may do, but we DO know that the other ingredients in normal detergents do a lot of harm, so we do have reason to think normal detergents are more harmful." This is actually the opposite of that objection, so it would have more of a strengthening effect. It makes the normal detergents sound more harmless, which makes it harder for us to argue that the eco-friendly detergents will be less harmful.

    4% picked this

  3. Different kinds of laundry detergents

    Weaker Impact

    This definitely weakens somewhat, because it raises doubt about whether it's fair to equalize normal and eco-friendly detergents by saying, "Well, they both have surfactants." With (A), we were objecting, "Yes, they both have surfactants, but not in the same quantity!" With (C), we'd be objecting, "Yes, they both have surfactants, but not equally harmful types of surfactants!" This answer could be correct if nothing else was stronger, but (A) is stronger because it specifically tells us that normal detergents have the higher (thus more harmful) level of surfactants in them. This answer doesn't specify whether normal detergents or eco-friendly ones have the more harmful type of surfactants. So it has unclear impact. It does raise the possibility that normal detergents have a worse form of surfactants, but that's not as strong as (A), which specifically attaches a negative to normal detergents.

    6% picked this

  4. There is reason to suppose

    Unclear Impact

    This doesn't allow us to compare eco-friendly to normal detergents, because it doesn't call out any difference between them. It lets us know that the other ingredients could really matter, but it isn't giving us any information about those other ingredients. Are these potentially more-harmful ingredients found only in normal detergents (weakens), only in eco-friendly (strengthens), or both (strengthens)? Without knowing more about how this answer relates to our head-to-head comparison, it has no clear impact.

    4% picked this

  5. Laundry detergents advertised as environmentally

    Strengthens

    This is sort of the inverse of (A). Regardless of the unknown effects of the other ingredients, we know that eco-friendly (like normal) detergents have surfactants, which can be harmful. If use of eco-friendly detergents requires larger amounts, then that suggests that using eco-friendly detergents involves larger amounts of surfactants, which inherently seems worse for the environment.

    2% picked this

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