Self-study
Economist: Support In the interaction between producers and consumers, the only obligation that all parties have is to act in the best interests of their own side. ███ ████████████ ██ ███████████ █████ ███████ ███████ ██ ██ ███ ████ █████████ ██ ███ █████████ ██ █████████ ███ ██████ █████████ ██ ██████ ███████ ███████ ████ █████████ █████ █████████ ███ █████ █████████ ██ ██████ █████
Objective: Find the Necessary Assumption
The economist's conclusion includes two claims: first, that consumers are always obligated to report product defects, and second, that producers are never obligated to reveal defects. This is based on the principle that both producers and consumers are obligated to act in their own interests; in fact, this is their only obligation. And we know that spreading information about defects is in consumers’ interests.
We're looking for a necessary assumption in this argument, which means the correct answer has to fill in a missing premise that is absolutely required by the argument. We can find this missing piece by looking at the economist's conclusion, which contains two claims. Of the two claims, only one of them—that consumers must always report product defects—is actually backed up by the premises. Conversely, the second claim, that producers are never obligated to reveal defects, doesn't actually follow from the premises: we know that producers must act in their own best interests, but we have no premise telling us how revealing product defects would fit into that.
In fact, in order to conclude that producers are never obligated to reveal defects, it must be the case that revealing defects is never in the producers’ interests; otherwise, they would sometimes be obligated to reveal defects, because they're obligated to do whatever is in their interests. So this is a necessary premise that isn't stated, also known as a necessary assumption. The argument depends on the assumption that revealing product defects is never in producers’ interests.
8.
Which one of the following ██ ██ ██████████ ████████ ██ ███ ███████████ █████████
a
It is never ██ ███ ████ █████████ ██ █████████ ███ █ ████████ ██ ██████ █ ███████ ███████
This must be assumed for the conclusion to follow—specifically its second claim, that producers are never obligated to reveal defects. Applying the negation test to (A), we get "revealing product defects is sometimes in producers’ interests." This would mean that producers are sometimes obligated to reveal defects, which destroys the economist's conclusion. So, for the conclusion to stand, (A) is necessary.
b
No one expects █████████ ██ ███ ██ █ ██████ ███████ ██ █████ ███ ████ ██████████
People’s expectations are irrelevant, because the economist only makes a claim about the obligations of consumers and producers. As far as we know, people's expectations don't make a difference to producers' and consumers' obligations, so keeping or losing this assumption wouldn't affect the argument.
c
Any product defect ██ ██████ ██ ██ ██████████ ██ ██████████
The economist only makes claims about what producers and consumers are obligated to do, not about what’s likely to occur. As far as we know, the likelihood of a defect being found has no bearing on either party's obligations to share information about defects. So because (C) is outside the scope of the argument, it can't be necessary to assume.
d
A product defect ██ ████ ██████ ██ ██ ██████████ ██ █ ████████ ████ ██ █ █████████
As with (C), it doesn’t matter who’s more likely to discover a defect. The economist's argument is only about whether consumers and producers are obligated to share information about defects, and the likelihood of finding such information doesn't affect those obligations. So the argument doesn't rely on (D).
e
The best interests ██ █████████ █████ ████████ ████ ███ ████ █████████ ██ ██████████
(E) would be a sufficient assumption to guarantee that producers are never obligated to reveal defects, but it's not necessary—it goes too far. The economist's conclusion is just about product defects, but saying that consumers' and producers' interests never coincide applies way beyond product defects; in other words, outside the scope of the argument. That means that a lesser claim could suffice; we don't really need (E).
Comparing (E) to (A), we can see the difference: (A) is specific to product defects, and doesn't go past the gap in the argument. (E) isn't necessary because although the argument requires assuming that revealing defects is not in producers’ interests, it's still entirely possible for their interests to overlap with those of consumers in other situations.