What logical fallacy occurs when someone asserts that a claim must be true because an expert believes it?

The assertion that a claim is true solely because an expert believes it exemplifies the Appeal to Authority fallacy. This fallacy arises when an argument is based on the credibility of the person making the claim, rather than on sound evidence or reasoning. While it can sometimes be reasonable to rely on expert opinion, it becomes fallacious when the argument presupposes that the expert is infallible or that experts cannot disagree on matters of opinion or interpretation.

In instances where individuals accept a claim exclusively due to the authority of an expert, without considering other supporting evidence or viewpoints, they fall victim to this fallacy. Therefore, while expertise may lend weight to an argument, it should not be the sole reason for accepting a claim as truth, emphasizing the need for critical evaluation of the underlying evidence. This practice is essential in making informed decisions and arguments.