Logical reasoning PrepTest 143 · Section 4 · Question 24

Incorrect. The assumption of the argument is about how age relates to approaching a stranger. If someone feels uncomfortable approaching someone they know of a different age, the argument still holds together, so the argument doesn't assume this connection.

Incorrect. There's no jump between similar situations in the stimulus, so this answer is out of scope.

Incorrect. The argument doesn't bring up different levels of likelihood, so this answer doesn't address the stimulus.

Incorrect. While friendships generally start with someone feeling comfortable approaching a stranger, there could be other interactions that don't lead to friendship where someone approaches a stranger without feeling comfortable.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
About same age → Likely to feel comfortable approaching stranger
Long-term friendship-most-Being with someone feeling comfortable approaching stranger
Therefore: Long-term friendship-most-About the same age

Answer Anticipation:
There's conditional logic in this stimulus, but it's a bit messy, so we should make sure that we can see if it's related to the flaw.

In this argument, the two statements both discuss feeling comfortable approaching a stranger. The conditional premise establishes that if you are the same age as a stranger, you will feel comfortable approaching them. And since most friendships begin by approaching a stranger, the argument argues, most long-term friends are probably about the same age.

So how do those premises work together? The argument is trying to combine them, but it's doing so incorrectly. In order for friendship to be between people of the same age, then most friendships must have started when someone approached someone else of the same age. However, the argument instead establishes that most friendships started when someone approached a stranger. While that might have been someone the same age, the conditional says that if you are the same age as someone, then you feel comfortable approaching them—it doesn't say only if you are the same age as someone.

The argument, in reaching its conclusion, treats the conditional as stating being the same age is necessary for feeling comfortable in approaching a stranger, but it actually establishes it as sufficient. This reversal is a flaw of the argument, so we should find an answer discussing it.

Answer Explanation:
This answer isn't a straightforward illegal reversal answer, but it does discuss the two terms from the statement we know the argument reversed, so we should consider it. In bringing up something the argument fails to address, this answer is raising a possibility that should undermine the argument. If someone is likely to feel comfortable approaching a stranger who isn't their age, then that does, in fact, call into question whether long-term friends—who generally started when someone felt comfortable approaching a stranger—are about the same age. In bringing up the possibility that the necessary condition of the conditional could exist without the sufficient condition, this argument is highlighting that the argument treats that conditional incorrectly, and so this answer is correct.

Key Takeaway:
Errors in Reasoning questions that feature conditional logic will generally commit a conditional logic flaw—an illegal reversal or negation. However, some of the harder questions won't phrase the answer in a normal way, and you'll have to dig into those answers. Whenever you see an answer that brings up the conditions from a conditional statement that you know the argument treats in a flawed manner, you should dig in to see if it's describing an illegal reversal or negation in non-standard language!