The argument from authority is a weak, but useful argument if used correctly. While people rarely follow the “strict” form of the argument, using it is to infer that a claim is true based on the (alleged) expertise of the person making the claim. Unlike deductive logic, the quality of an argument from authority does not depend on its logical structure but the quality of the expert making the claim. As a practical matter, anyone could be used as an “expert” in an argument from authority. For example, someone might claim that secondhand smoke does not cause cancer because Michael Crichton claimed that it does not. At least he did before he died. As another example, someone might claim that astral projection/travel is real because Michael Crichton also claims it can occur. Given that people often disagree, it is also quite common to find that alleged experts disagree with each other. For example, most medical experts claim that secondhand smoke does cause cancer. They do not, of course, claim that everyone who is exposed to it will get cancer or that no one who is not exposed to it will not get cancer. This is a claim about causation in populations: if everyone was exposed to secondhand smoke, then there would be more cases of cancer than if no one was.
If you are an expert in a field, you can pick between the other experts by using your own expertise. For example, a medical doctor who is trying to decide whether to believe that secondhand smoke causes cancer can examine the literature and perhaps even conduct her own studies. Being an (actual) expert means being qualified to make an informed pick. An obvious problem is, of course, that experts pick different experts to accept as being correct.
The problem is far greater when it involves non-experts trying to pick between experts (and perhaps alleged experts). Being non-experts, they lack the expertise to make informed choices about which expert is most likely to be right. This raises the question of how to pick between experts when you are not an expert.
Not surprisingly, people tend to pick based on fallacious reasoning. One approach is to pick an expert because she agrees with what you already believe. This is not good reasoning: to infer that something is true simply because I believe it gets things backwards. It should be first established that a claim is probably true, then it should be believed (with appropriate reservations).
Another common approach is to believe an expert because they make a claim you want to be true. For example, a smoker might elect to believe someone who claims secondhand smoke does not cause cancer because he does not want to believe he might increase the chance that his kids will get cancer. This “reasoning” is the fallacy of wishful thinking. Obviously enough, wishing that something is true (or false) does not prove that the claim is true (or false).
People also pick their expert based on qualities they see as positive but that are irrelevant to the person’s (logical) credibility. Factors such as height, gender, appearance, age, personality, religion, political party, wealth, friendliness, backstory, courage, and so on can influence people emotionally, but are not relevant to assessing a person’s expertise. For example, a person giving you advice about warts might be very likeable but be completely wrong about how warts should be treated.
Fortunately, there standards for recognizing an expert. They are as follows.
- The person has sufficient expertise in the subject matter in question.
Claims made by a person who lacks the needed degree of expertise to make a reliable claim will not be well supported. In contrast, a person who has expertise in a subject is more likely to be right about claims in their field. The challenge is being able to judge whether a person has sufficient expertise. In general, the question is whether a person has the relevant qualities and these are assessed in terms of such factors as education, experience, reputation, accomplishments and positions.
- The claim being made by the person is within her area(s) of expertise.
If a person makes a claim about a subject outside of their expertise, then their expertise does not apply. Hence, the claim is not backed by the expertise and is not reliable. People often mistake expertise in one area (or being a celebrity) for expertise in another area. For example, an expert physicist’s claims about politics or ethics are not backed up by their expertise in physics. A person can be an expert in more than one field and there are cases where expertise in one field can be relevant in another. For example, a physicist who is also a professional ethicist would be an expert in both fields. As another example, a physicist’s expertise in nuclear weapons could be relevant to claims made in politics or ethics about nuclear weapons.
- The claims made by the expert are consistent with the views of the majority of qualified experts in the field.
This is a very important factor. As a rule, a claim that is held as correct by the majority of qualified experts in the field is the most plausible claim. The majority of experts are more likely to be right than those who disagree with the majority.
As no field has complete agreement, a degree of dispute is acceptable. How much is acceptable is, of course, a matter of serious debate.
It is also important to be aware that the majority could be wrong. That said, it is reasonable for non-experts to go with the majority opinion because non-experts are, by definition, not experts. If I am not an expert in a field, I would be hard pressed to justify picking the expert I happen to like or agree with against the view of the majority of experts.
- The person in question is not significantly biased.
Experts, being people, are subject to biases and prejudices. If someone is biased in a way that would affect the reliability of their claims, then their credibility is reduced. This is because there would be reason to believe that the claim is being made because of bias or prejudice. For example, an expert being paid by an oil company who claims that fossil fuels are not causing climate change would be biased. But a biased expert’s claims could still be correct.
No one is completely objective and a person will favor their own views. Because of this, some degree of bias must be accepted, provided that the bias is not significant. What counts as a significant degree of bias is open to dispute and can vary from case to case. For example, most would suspect that researchers who receive funding from pharmaceutical companies will be biased while others might claim that the money would not sway them if the drugs proved ineffective or harmful.
Disagreement over bias can itself be a significant dispute. For example, those who doubt that climate change is real often assert that the climate experts are biased. Questioning an expert based on potential bias is a legitimate approach—if there is adequate evidence of bias that would be strong enough to unduly influence them One way to look for bias is to consider whether the expert is interested or disinterested. Or, more metaphorically, to consider whether they have “skin in the game” and stand to gain (or suffer a loss) from their claim being accepted as true. Merely disagreeing with an expert is, obviously, not proof that an expert is biased. Vague accusations that the expert has “liberal” or “conservative” views also do not count as adequate evidence. What is needed is actual evidence of bias. Anything else is most likely a mere ad homimen attack.
These standards are not infallible. However, they do provide a guide to logically picking an expert to believe. They are certainly more logical than just picking the one who says things one likes.