Flaws in Logical Reasoning Part VIII: Appeal to Authority

Before continuing on to Part Eight of our flaws in LR on the LSAT, let’s review once more. Here’s how I began the first post in this series, where we looked at Source Arguments:

The majority of LSAT Logical Reasoning questions have an argument in their stimulus and most will contain some sort of flawed reasoning. In this series, we will address a variety of the flaws that tend to appear with some frequency. I’ll examine common mistakes that authors on the test make. This should prove useful for Flaw in the Reasoning questions (which account for about 15% of LR questions.) It should also help with other question types that require you to respond to argumentation.

This next mistake LSAT authors make has some real-world applicability, as well.

Appeal to Authority

I suppose this could just as easily be titled, “Appeal to Improper Authority”. This error occurs when an argument is based on evidence provided by someone who could be considered a person of authority/expertise on a subject, or in a field, but is not necessarily related to the subject in the conclusion. To put it differently, just because someone is an expert regarding one topic, does not necessarily qualify that person to speak with authority on other topics. Here’s an example.

“World-renowned physicist Dr. Patricia Mitchell assures me that exposure to natural sunlight, even exposure resulting in mild sunburn, is still significantly less of a cancer risk than brief exposure to the artificial light in a tanning bed. So I make sure to tell all of my friends that if they’re looking to get a tan this summer they should do it outdoors, and not at the tanning salon!”

Granted, we could probably point out a number of errors here. Perhaps the most glaring is that the author concludes that tanning outdoors is preferable to tanning in a salon based on the opinion of a physicist. There is no reason to believe a physicist would have compelling or relevant insights into biological processes like cancer development. If she was a dermatologist or a general practice doctor, her expertise would be more applicable and persuasive. But, you cannot presume a physicist to be an authority in a field far removed from her area of achievement.

How to Spot it on the LSAT

Here’s how this type of error would likely be represented in an answer choice.

• “the judgment of experts is applied to a matter in which their expertise is not relevant”
• “the argument improperly appeals to the authority of the supervisor”
• “bases a conclusion solely on the authority of the claimant, without seeking further proof”

Two final points to consider regarding Appeal to Authority errors:

1. On rare occasions, a conclusion will be based on the authority of a person/group whose expertise does seem to apply to the subject at hand. However, another person or group with equally relevant authority will offer contradictory evidence or claims. In this case, the Appeal to Authority error still exists. Instead of appealing to an improper authority, the author makes the mistake of discounting one authority in favor of another. Even though there is no clear indication of which authority should be considered correct. Two equally authoritative sources with contradictory views simply indicate that a strong conclusion in either direction is questionable.
2. When multiple authorities are sited, the test makers won’t test your ability to determine degrees of authority or relevant knowledge. For instance, let’s re-use the tanning example above. They wouldn’t have a dermatologist argue for tanning beds and an oncologist (cancer doctor) argue for sunlight, and then force you to decide which is more reliable authority on skin cancer.

Look out for any argument that draws a conclusion based on the opinions of an authoritative source or so-called “expert.” Just because someone is a reliable authority in one field doesn’t mean that expertise will be relevant to other fields.

[Further Reading in Flaws in Logical Reasoning: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10]