PrepTest 144

Incorrect. All three references to nutritional supplements seem to be referring to the same thing—some type of supplement that's not a pharmaceutical.

Incorrect. Armstrong specifically notes that we shouldn't rely on Dr. S's judgment because it's not trustworthy, so she doesn't rely on that appeal to authority.

Incorrect. There's no appeal to emotion here since the argument questions Dr. S's motives instead of calling for sympathy for sick people.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
Dr. S says to use nutritional supplements to treat a certain disease, but he's paid to endorse them, so we shouldn't use nutritional supplements for that disease.

Answer Anticipation:
There is a key flaw in this argument hinted at by elements of the stimulus, and there's a key flaw that isn't present hinted at by elements of the stimulus.

First, a flaw that isn't present but is hinted at—an inappropriate appeal to authority. While the argument does discuss the opinion of an expert, the conclusion runs counter to that expert's opinion. As such, it can't be said to inappropriately appeal to authority since it rejects that expert's opinion.

Now, to the flaw that is present. The argument calls someone's motives into question. That's a hint that there's an ad hominem flaw. Here, the argument doesn't address the benefits of nutritional supplements, instead attacking the motive of the person advocating for them. That ignores the argument to focus on the person behind it, so the argument commits a classic ad hominem attack.

Answer Explanation:
This answer highlights one of the two key flaws in the argument—the ad hominem attack. Instead of addressing whether nutritional supplements actually help cure this disease, Armstrong calls Dr. S's motives in recommending them into question. He could be self-interested and right—maybe he accepted the endorsement deal because he believes in the product!

Key Takeaway:
Any time you see a rebuttal that focuses on someone's motives in making an argument, immediately start to consider an ad hominem flaw. Someone can be biased, hypocritical, or have ulterior motives and still make a good argument.

Incorrect. The argument doesn't presume that nutritional supplements can't be used with pharmaceuticals. If that were the case, the argument would need to base its conclusion about these supplements on a premise about people not taking pharmaceuticals having worse results—thus assuming that people can only take one of the types of treatment.