In a group chat, someone forwards an internal report and says, “The data in this report is all reliable.” When asked how he knows, he answers, “The report states at the beginning that all data in this report has been verified.” When asked again whether the report itself is trustworthy, he answers, “The data has all been verified, so of course it is trustworthy.” Which of the following evaluations is most accurate?

Answer: C

• AData reliability and the report’s trustworthiness are two different things; his two answers each addressed a different aspect, so there is no problem.✗ Wrong. This mistakes “answering with different words” for “giving different grounds” — the report’s trustworthiness rests on the data being reliable, and the data’s reliability rests on the report’s own declaration, which is still one circle.
• BThe first answer can be accepted, because a report’s self-audit of its data is standard industry practice and counts as common-sense evidence.✗ Wrong. Even if self-auditing is common practice, this report’s reliability claim cannot serve as standalone evidence, because it is precisely a guarantee issued by the very object under question.
• CHis reasons all come from the report itself; the report’s reliability is vouched for by the report itself, and after going in a circle nothing has been proven.✓ Correct. Someone who does not yet trust this report would not accept it merely because the report claims its data has been verified; the reason only holds if the conclusion is granted in advance.
• DThe problem is that he blindly trusts authority, treating the report’s authors’ statements as the final authority.✗ Wrong. The key is not “trusting authority,” but that the report’s statement could only hold if we first assume the report is reliable — that is, using the conclusion to prove the conclusion.