The makers of Activite, a natural dietary supplement, claim that it promotes energy and mental alertness. To back up their claim, they offer a month’s supply of Activite free to new customers. Clearly, Activite must be effective, since otherwise it would not be in the company’s interest to make such an offer.

Summarize Argument
The author concludes that Activate is effective. This is because the makers of Activate offer a free month’s supply to customers, which they wouldn’t do if Activate was ineffective.

Notable Assumptions
In order for the free sample to be in the company’s interest, the author assumes that the makers of Activate don’t get any benefit from the free sample, besides having potential customers try their product. Any hidden benefit, such as an investment agreement the company signed or a cash benefit the company gets from shipping their product, would weaken the author’s argument.

A
The nutrients in Activite can all be obtained from a sufficiently varied and well-balanced diet.
The author never said Activate is necessary. It’s simply a supplement that helps people who may otherwise, for whatever reason, not get those nutrients in their diet.
B
There are less expensive dietary supplements on the market that are just as effective as Activite.
Activate can still be effective even if it’s not the most cost-efficient.
C
A month is not a sufficient length of time for most dietary supplements to be fully effective.
Even if Activate doesn’t show itself to be “fully” effective in a month, it might still prove to be effective.
D
The makers of Activite charge a handling fee that is considerably more than what it costs them to pack and ship their product.
Activate’s makers ingeniously make money from the free sample. This gives us some other reason why the company would choose to offer the free samples.
E
The mere fact that a dietary supplement contains only natural ingredients does not insure that it has no harmful side effects.
The author has no stance on side effects. All that matters is whether sending free samples proves Activate is effective.

53 comments

Bird watcher: The decrease in the mourning-dove population in this area is probably a result of the loss of nesting habitat. Many mourning doves had formerly nested in the nearby orchards, but after overhead sprinklers were installed in the orchards last year, the doves ceased building nests there.

Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that the decrease in mourning-dove population is probably a result of the loss of nesting habitat. This is based on the fact that many doves had formerly nested in the nearby orchards, but the doves stopped building nests in the orchards after sprinklers were installed in the orchards.

Notable Assumptions
The author assumes that the doves’ stopping of nests in the orchards constitutes a loss of nesting habitat. The author also assumes that there aren’t enough other areas for doves to build nests that could make up for the loss of the orchards as a nest-building location. The author also assumes there’s no other explanation for the decrease in population aside from loss of nesting habitat.

A
Mourning doves were recently designated a migratory game species, meaning that they can be legally hunted.
If anything, this weakens the argument by providing a potential alternate explanation for the decrease in dove population (they began to be hunted).
B
The trees in the nearby orchards were the only type of trees in the area attractive to nesting mourning doves.
This strengthens by providing evidence that loss of the orchards as a nest-building location constitutes a loss of nesting habitat. If there had been other trees available that were attractive for nesting, then there wouldn’t necessarily be a loss of nesting habitat.
C
Blue jays that had nested in the orchards also ceased doing so after the sprinklers were installed.
This tells us another species stopped nesting in the orchards. But that doesn’t reveal whether the loss of the orchards was a loss of nesting habitat for mourning doves. We already know the doves stopped nesting in the orchards.
D
Many residents of the area fill their bird feeders with canola or wheat, which are appropriate seeds for attracting mourning doves.
This tells us that doves might feed at bird feeders. But it doesn’t have a clear impact on doves’ nesting options and whether their nesting habitat has decreased.
E
Mourning doves often nest in fruit trees.
Are fruit trees in orchards? Are they no longer available for nesting in the orchard? Are there fruit trees outside of the orchards? Without knowing the answers to these questions, (E) has no clear impact.

24 comments

Letter to the editor: When your newspaper reported the (admittedly extraordinary) claim by Mr. Hanlon that he saw an alien spaceship, the tone of your article was very skeptical despite the fact that Hanlon has over the years proved to be a trusted member of the community. If Hanlon claimed to have observed a rare natural phenomenon like a large meteor, your article would not have been skeptical. So your newspaper exhibits an unjustified bias.

Summary

Mr. Hanlon’s claim that he saw an alien spaceship was extraordinary.

The newspaper reported on this claim with a skeptical tone.

Mr. Hanlon has proved to be a trusted member of the community.

Hanlon claimed to have seen a rare natural phenomenon→ /Article would have skeptical

The newspaper exhibits unjustified bias.

Notable Valid Inferences

If the article was skeptical, then Hanlon’s claim wouldn’t have been about a rare natural phenomenon.

A
If a claim is extraordinary, it should not be presented uncritically unless it is backed by evidence of an extraordinarily high standard.

The letter conflicts with the principle in (A), which gives sufficient conditions for the newspaper to be skeptical. Hanlon’s situation met these conditions, so the newspaper should be skeptical. Yet, the letter argues the opposite—that the newspaper should not be skeptical.

B
One should be skeptical of claims that are based upon testimonial evidence that is acquired only through an intermediary source.

This principle does not apply. (B) discusses testimonial evidence acquired only through an intermediary source, but Hanlon’s evidence was provided directly.

C
If a media outlet has trusted a source in the past and the source has a good reputation, the outlet should continue to trust that source.

This principle does not apply. We know that Hanlon has been a trusted member of the community, but we don’t know if this newspaper has trusted Hanlon as a source in the past. We also don’t know anything about the newspaper’s reputation.

D
People who think they observe supernatural phenomena should not publicize that fact unless they can present corroborating evidence.

This principle does not apply to the letter’s argument. The argument in the letter is about the newspaper’s bias, but the principle in (D) would pertain to Hanlon’s actions.

E
A newspaper should not publish a report unless it is confirmed by an independent source.

This principle does not apply. (E) gives a principle for determining when a report shouldn’t be published, but the letter isn’t arguing about whether or not the report should have been published. Instead, the letter’s argument is about the newspaper’s bias.


43 comments