Logical reasoning PrepTest 127 · Section 3 · Question 9

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
Chain bookstores getting big caused indie bookstores to close. This has caused the increase in the variety of available books to slow. Therefore, chain bookstores have hurt book consumers.

Answer Anticipation:
This argument features a causal conclusion (implied by the phrase "has been to the detriment," which suggests they've had a negative effect), so we should start by considering a correlation/causation flaw.

However, upon looking at the premises, we can see that they, too, are causal ("largely because," "has prevented"). Causal premises can validly support a causal conclusion, so there's no correlation/causation flaw here.

When an argument is chaining causal statements together, there are a few common errors we can look out for:
(1) The argument jumps between terms in the chain, failing to establish a relevant connection
(2) The argument tries to take the contrapositive—the effect missing doesn't necessarily mean the cause is missing, as well, as most causal claims are statistical and not certain
(3) Similar to #2, the argument treats a cause as the only potential cause

Of these #2 and #3 can be ruled out. For #2, the argument doesn't look at a situation where consumers weren't hurt. For #3, the argument concludes that the success of chain bookstores has hurt book consumers—that language brings it up as a factor, but not necessarily the only factor.

So we're left with #1, and looking at the conclusion and the premises shows that there is a jump. The premise chain establishes that the growth of the chain bookstore has resulted in a slowdown in the growth of the variety of available books. The conclusion says that the growth of those bookstores has hurt consumers. There's a jump there between the decline in the growth of variety and a detriment to consumers. Therefore, the correct answer will likely suggest that that slowdown does hurt consumers.

Answer Explanation:
This answer connects the effect of chain bookstores that's established in the premises to the judgment in the conclusion that those stores have hurt book consumers. If the reduced variety doesn't hurt book consumers, then the argument falls apart.

Key Takeaway:
Arguments can validly chain causal premises together to form a causal conclusion, but there are some common flaws associated with that type of argument:
(1) The argument jumps between terms in the chain, failing to establish a relevant connection
(2) The argument tries to take the contrapositive—the effect missing doesn't necessarily mean the cause is missing, as well, as most causal claims are statistical and not certain
(3) Similar to #2, the argument treats a cause as the only potential cause

Incorrect. The argument does rely on there being more variety of books with independent bookstores, but that could happen even if there is overlap in what the indie stores and chain stores carry—as long as the indie stores also carry other books that the chains don't.

Incorrect. There's no discussion of store size in the stimulus, and it's not inherently related to book variety (a larger store could have more unique titles, or it could sell only many copies of the 50 most popular books of all time). As such, this answer is out of scope.

Incorrect. Similar to (C), there's no discussion of store size in the stimulus, and store size isn't inherently tied to the variety of books being sold, so this answer is out of scope.

Incorrect. First, this answer downplays the importance of book variety to book consumers, which cuts against the argument. Second, this is a relative statement—while prices may be more important to some than variety, they could still be hurt with less variety.