When and Why Should We Believe Experts?

Professor Quasimodo says that we should brush our teeth twice a day and Professor Mosiquado says that brushing teeth has no dental benefits and is a complete waste of time.

They’re both dental experts! How do we figure out what to believe in a case like this? Well, here’s one promising model:

We should trust what an expert says about X if and only if the expert is relaying the consensus position of relevant experts (or CPORE) about X.

Now, there will certainly be places where there is no consensus position, or the consensus is muddied by irrelevant expert opinions. And sure, figuring out what the consensus position is, when there is one, and who the relevant experts are are not always straightforward. And there may well be some ambiguity in our concepts! There are entire bodies of literature dedicated to hammering out the details into coherent accounts, but even absent a rigorous conceptual analysis of “consensus” or “expert” or “expertise” this model can still be helpful.

Let’s illustrate how by running our initial example through the CPORE model. Even though Professors Quasimodo and Mosiquado are experts in a relevant subject for the issue at hand, namely brushing teeth, we ought to believe experts, even experts in the relevant subject matter, only when they are reporting the consensus position of the relevant experts (CPORE). Mosiquado is not relaying CPORE whereas Quasimodo is. The American Dental Association and the British National Heath Service recommend brushing teeth twice a day. Even if Mosiquado has discovered some evidence that brushing teeth is ineffective, it would be irrational (or unreasonable) to believe him over CPORE.

Truth and Rationality

This is not to say that CPORE is always the true view. In fact, there are lots of occasions where the CPORE turned out to be incorrect. One of the most famous examples in the history of medicine is that of stomach ulcer formation. For a long time, CPORE about stomach (or peptic) ulcers—small ruptures in the stomach lining—was that they were caused by increased acidity brought on by the consumption of spicy foods. The dictum of “no acid, no ulcer” was the accepted view among medical professionals world-wide. There was even good evidence for this view, particularly the fact that antacids helped relieve symptoms for patients experiencing peptic ulcer disease. However, we now know that this is simply not the case. Diet plays no, or at least no significant, role in peptic ulcer disease, rather it is caused by a type of bacteria known as Helicobacter pylori or H. Pylori. Experts began to notice that CPORE did not explain all of the data as well as the new H. Pylori view did. As a result, the old CPORE that spicy foods caused peptic ulcers gradually evolved into the CPORE that H. Pylori caused peptic ulcers. This is how science works.

Now, imagine that you were alive as this paradigm shift was taking place—(perhaps you were since this happened in the 1980s). As a non-expert in the relevant subject matter, would it have been reasonable for you to believe that H. Pylori, and not spicy food, ­was the cause of peptic ulcers? Probably not. It would have been silly for you to reject CPORE in favor of the alternative account.

But that’s crazy! How can you say it’s unreasonable to believe the truth?!

Well, given your inability as a non-expert to adjudicate between the competing hypotheses, it would be silly of you to adopt the non-CPORE view. You could not base that belief on any good reasons. As a non-expert, you simply don’t have access to the relevant reasons for rejecting CPORE. Your belief in the H. Pylori hypothesis would be akin to someone deciding to believe that there are an odd number of stars in the universe. Such a person would not have good reasons for that belief.

This brings out a couple of important points about the rationality, or reasonableness, or belief. First, that expertise does not lie with individuals, but in communities. You can’t do science or any other discipline, for that matter, on an island on your own without input from colleagues both contemporaneously and the giants on whose shoulders you can stand. If you grew up on a remote island by yourself, you’d not even be able to build a canoe much less lasers, refrigerators, and cars. You wouldn’t know that George Washington was the first president of the United States, or that he even existed. You wouldn’t know that the great ball of fire in the sky was a star.

This leads into the second point which is that we form most of our beliefs on the basis of testimony—we can’t avoid it. If we had no one else around us, we’d not have anywhere near as many beliefs as we do now. Maybe 10. Or 14.

Inevitability of Expertise

Even if you pride yourself on rejecting the importance of expertise, all you’ve done is simply substitute one set of experts for another. Those who disregard expert opinions really just mean to say that the majority has been duped and that the truth lies elsewhere, typically in some fringe view. But the problem is that you can’t know that. And additionally, that, itself, is still reliance on perceived expert testimony. Those folks may or may not be experts—but you treat them as such when you base your beliefs on their testimony. This is why conspiracy theories are not based on rejections of expertise per se rather they simply substitute one community of experts for another community of “experts”. Additionally, skepticism of expertise is seldom applied consistently. Think about all of the beliefs that you could only form because we have communities of expertise.

One CPORE that you accept (hopefully) is that the Holocaust did, in fact, take place—that between six and eleven million people were killed by the Nazi regime. Other CPOREs include:

-Cancer is terrible for your body and not, rather, your metamorphosis into a super-human.

-The moon is not, in fact, made of cheese

-The phone or computer you’re using to read this is not a bomb set to detonate two months from now

When you reject the CPORE in favor of another view, you’ve substituted one set of sources in favor of another. But how did you arrive at the conclusion that the new set of sources is reliable? As a non-expert, yourself, how can you possibly know that the information from Group B is more trustworthy, accurate, reliable, etc.? You can’t. As a non-expert, you can’t know that H, Pylori is actually the cause of peptic ulcers contra the CPORE. You simply aren’t qualified to make that assessment. For all your claims to enlightenment, you’re just parroting whatever information you got from this alternative source. You’ve done the equivalent of deciding to believe that there are an odd number of stars. Such a belief has no more merit than one acquired by throwing a dart at a wall of possible beliefs about the world.

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