Logical Reasoning

PT155 · S1 · Q10 Dentist: Five recently conducted studies

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Dentist: Five recently conducted studies all show that the proportion of children with decayed, missing, or filled teeth is lower in Europe, where water is not fluoridated, than in the United States, where it is.

Conclusion (this is evidence that)

Fluoridation of water does not have a substantial tendency to prevent tooth decay.

Evidence

In five studies, the US (where water is fluoridated) had higher rates of decayed / missing / filled teeth than did Europe, where water is not fluoridated.

Evaluate

This argument has an Anti-Causal conclusion. The author is saying that fluoridation doesn’t do a certain thing. How would someone object to this? How could someone accept the reports of the five studies but still argue that fluoridation does help prevent tooth decay?

When we’re trying to make anti-causal objections, we’re generally making one of two types of claims:

- hey, those two groups aren’t fair to compare - hey, it would be even better/worse without this thing

Someone might object that Europe and the U.S. aren’t fair to compare. There are different factors in each place that would impact dental health in children differently. Maybe the tap water in the U.S. rots our teeth, or maybe we drink more soda or do a poorer job flossing / brushing.

Another way to express this same type of objection is by saying,

Goal

Since this is strengthen, a correct answer could try to eliminate either of these lines of objection: there are not things like bad tap water, sugary sodas, bad brushing habits that make American teeth way worse than European teeth (that make them unfair to compare).

Or the correct answer might just present new evidence that makes it sound like fluoridation doesn’t have much effect on preventing tooth decay.

10.

Which one of the following, if true, would most strengthen the dentist's argument?

Toothpaste containing fluoride is widely
Unclear Impact
The fact that fluoridated toothpaste is available doesn’t tell us to what extent American vs. European kids are using it. Even if they’re both using it, American kids are getting additional fluoride through their water.
5% picked this
Nearly all dentists in the
Weakens, if anything
Learning that almost all dentists think applying fluoride directly to teeth is worthwhile goes against the conclusion and makes it seem like fluoridation does help promote dental health.
16% picked this
Dental hygiene is typically taught
Weak Impact
This somewhat goes against the potential objection that “fluoridation helps American kids’ teeth; the reason their teeth compare unfavorably to European children’s is that American kids don’t brush as well.” Does having dental hygiene taught in elementary school establish that American children brush as well as European children? Certainly not, but it nudges in that direction, so it somewhat goes against a potential objection like “poor brushing by the American kids is the real reason that their teeth seem worse”. However, this suggestive nudge is not as powerful as the correct answer.
4% picked this
On average, children in Europe
Weakens
This provides a potential factor for why European teeth would be better than American teeth. If European children receive more dental checkups, then they will probably have healthier teeth, all other things being equal. Thus, American children’s teeth might still be helped by fluoridated water. It’s just that the help fluoridated water provides isn’t enough to catch them up with the superior European teeth.
11% picked this
Correct
The diets of children in
Why this is right
This is pushing back against a possible line of objection. Someone could try to argue that, “Fluoridation absolutely helps prevent tooth decay! The only reason that American kids, who drink fluoridated water, have worse teeth than European kids who drink un-fluoridated water is that American kids have a diet that is worse for teeth (lots of sugary foods and beverages).” If the diets were very different, in terms of their effect on teeth, then it wouldn’t be fair to compare the European kids’ teeth to American kids’ teeth. By ruling out this objection, this answer is making the comparison seem more legit. “American and European kids essentially eat foods that would rot their teeth in a similar way. And yet, since American kids (whose water is fluoridated) have more tooth problems than European kids (whose water is not), it looks like fluoridation isn’t doing much.”
Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.
65% picked this

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