PrepTest 134

Incorrect. The argument also doesn't establish that any of the companies actually on the list would want to belong, and yet there they are. Evidence can support that someone is a member of a group without speaking to their desire to be a member. In other words, a conclusion can be established without establishing every possible premise.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
J: A secretive trade group sent me a list of companies. They confirmed: List → Member. Bruch isn't on the list, so they're not a member.

Answer Anticipation:
We delved into conditional logic a bit in our Summary, but it wasn't necessary to do so to see the flaw here. The Journalist was sent what appears to be a list of members of the trade group. However, while it is confirmed that everyone on the list is a member, it was never confirmed that everyone who is a member is on the list. As such, the Journalist's conclusion is flawed. Whether you saw it as an illegal reversal, illegal negation, or an assumption that a partial list was a complete one, you should end up at the same answer.

Answer Explanation:
The stimulus establishes that the list is of members of the group, but it never confirms that the list is of every member of the group. The Journalist could have a partial list. This answer highlights the flaw in the reasoning.

Key Takeaway:
While not as complete a relationship as with words such as "if" and "only," any word that denotes 100% of a group (each/any/all/every/none) can be turned into a conditional statement. This can be helpful in analyzing the logic of arguments to see how a statement about a group may be misconstrued in forming a conclusion!

Incorrect. How it could have happened is irrelevant, since it apparently did happen.

Incorrect. Since the argument concludes that Bruch isn't in the trade group, it's not assuming anything about what it would want if it were in the trade group. This answer would only be relevant if the argument relied on something about Bruch to conclude that it wasn't in the group, not the list of members.

Incorrect. The trade group would have reason to deny the accuracy of the list, not confirm it, so there's no reason to think that the accuracy of the statement made is in question.