On the question of whether the United States is headed for an inflationary period or a deflationary period, highly trained economists are divided. This today at the Economist:
Last week, we launched our economics channel with a debate on whether inflation or deflation is the greater threat. Scroll through the contributions and you will discover either that “Tough deflationary times lie ahead” or that “Eventual inflation is inevitable”. Since this is the central question of economic policy at the moment, such a discordance of views is rather disturbing; much is made of the debate on global warming but the scientific consensus is overwhelmingly on one side on that issue. On economics, governments are being forced to choose in matters of fiscal austerity, where the debate is almost 50-50.
So what do you believe (let alone do) when specialists in a technical field collide? Proportion your belief to the evidence? But the experts (in the case of inflation v. deflation) are divided on the evidence, and surely you don’t imagine yourself competent to adjudicate the evidence for yourself, do you?
In such a circumstance, if you are an elected official trying to digest conflicting economic advice from equally qualified experts, perhaps it is best just to flip a coin (or go to grad school). Or do nothing at all.
Prometheus Unbound 
Experts? When it comes to the gray sciences (sociology, economics, etc…) there is no such thing as an expert, only people who think they’re experts.
Andrew:
I’m not so sure that’s true about economics. But you are right to suggest that if the (unverifiable) theory underlying a discipline is unsound in the real world, then the expert is just guessing. But I do think it is fair to give weight to people who are highly trained in disciplines like economics. It’s not all just an ideological exercise.
—Santi
Sure it is. If you can’t show causality, then it’s not real science. Correlation means nothing. The best answer to the demarcation problem by far.
Disagreement among experts is pretty common in many areas that aspire at least to be science. Look at the endless debate on global warming, what foods are healthy, and more. Doesn’t science usually provide truth that is subject to further testing and found wanting? Newtonian physics worked for most things, but had trouble with explaining the orbit of Mercury. A newer model of space being bent replaced it. Science hardly deals only with that that is universally and forever settled.
Brucetheeconomist:
Your point is taken, but as a lay person, if I hear that astronomers and physicists are agreed that the universe is 13.7 billion years old, I may not have the ability to understand the math underlying the arguments, but I am certainly justified in apportioning my belief to their agreement (based on their expertise). Don’t you agree? If, however, I (again, as a lay person) learn that scientists are sharply divided on whether, say, life exists on Mars, then it is sensible to be agnostic on the matter myself. Isn’t that also the reasonable position?
In an imperfect world, expert testimony (especially when experts overwhelmingly agree on a subject) ought to be considered a form of pretty reliable knowledge. And where opinions among experts are sharply divided, the reasonable position for a lay person is agnosticism. At least that is my opinion.
—Santi
I was only suggesting that experts in a field disagreeing isn’t an indication that a field isn’t science. I thought Andrew had suggested this.
Bruce:
Oops. My mistake, then.
—Santi
That’s not really what I meant. Disagreements over the demarcation problem (what is and isn’t science) are things experts will disagree on. Of course sometimes an expert or experts are completely wrong. Sometimes they disagree. It’s important to have a way of understanding what is true and what isn’t without having to blindly believe in expert opinions. Do you select a few trusted experts? Do you restrict the type of evidence that you consider valid? I simply draw the line at causation, and view corollary evidence as being worth very little.
Andrew:
You’re a snake chasing your tail. If you don’t have access to the arguments of experts—because, as a lay person, you don’t know, say, the math that is being appealed to—then the reasonable fall-back is to look at what you do know, which is this: highly trained people, arriving at a strong consensus (such as, say, evolution being true), are far more likely to be right than wrong. In an imperfect world, it’s what a lay person has to work with.
The complexities of our contemporary existence mean that we have to have a “philosophy of experts”—a philosophy that incorporates (does not ignore) expert opinion. A lay person should not assume that all aspects of the world are accessible to him or her in such a way that he or she can take a cursory look at something (again, like the evidence for evolution) and pretend to see the issue clearer than experts trained in biology or paleontology.
Are there biases and group think within expert communities? Yes. Do they overwhelm rationality and evidence? Sometimes. Can we, nevertheless, have greater confidence in the consensus of experts on a subject than in the consensus of nonexperts? Yes, of course.
I think that there is an important distinction to make between authority and expertise. We should not, in argument, appeal to authority. But it is rational to appeal to expertise. In a complex world, human beings have set up systematic communities devoted to basing opinions on reason and evidence. We call such communities scientific and technical communities (from climatology to medicine). What the experts in such fields discover together in a process of dialogue and exploration of evidence is important to incorporate into our worldviews.
—Santi
Andrew:
Another thought about this. I think that you can work out additional principles for evaluating expertise (that are readily and rationally available to the lay person). Here are four:
1. How well respected by fellow experts is the expert making a claim?
2. Does this expert’s claim go with—or against—the consensus of his or her discipline?
3. Does the expert have external motivations that might be distorting his or her judgment?
4. Is the expert speaking directly to his or her expertise, or to something peripheral to it?
These are things that, without direct analysis of evidence, that a lay person can reasonably ask of an expert in any field. And to not ask these questions, and take them into serious account, is to be irrational (however much you might appeal to your interpretation of the technical evidence that the expert is speaking to).
One thing, for example, that creationists frequently do is call the discipline of biology a priesthood, a “church” etc.
This is a way of undermining the credibility of communities of reason and evidence that have grown over the past several centuries (since the Enlightenment). Creationists seek to conflate authority and expertise so that people don’t think clearly about the Enlightenment project (which is Kant’s “dare to know” via specialized disciplines devoted to dialogue, reason, and critical appeals to evidence).
—Santi
Santi,
those are all heuristics. You say you were raised in a fundamentalist Christian household. Why reject the authority of theologians who have dedicated decades to Biblical study? What separates ‘expertise’ from ‘authority?’
You can not shortcut knowledge. The only reason one can know that homeopathy is a pseudo science and immunization is a useful medicinal weapon against disease is by knowing a bit of physics and biology. False prophets (to use a pointed phrase) adopt all the styles of ‘expertise.’ They feign modesty and position themselves as anti-establishment when they’re on the outs (like with creationists) and they use arguments from authority when they’re in power (like how psychologists ‘proved’ that women were mentally and emotionally unstable compared to men only a century ago.)
There’s nothing wrong with going by what the ‘experts’ say without really understanding it, as a default. We can’t know everything and some things we have to take on faith (though we don’t have to agree on what those things are.) But as the title asks, what do you do when the ‘experts’ disagree? And if you or I question a point of “common knowledge” the retort, “Well that’s what the experts say,” is far from satisfying.
I reject Sociology, Economics, and Psychology (to name a few) as fields where the experts should be listened to not out of some anti-expert contrarian heuristic. And also not because there are several schools of each that constantly disagree with one another, but because they have no scientific basis by which to resolve their disagreements. Psychology may soon become a real science, as neuroscience is making leaps and bounds (though I’d just as soon keep neuroscience and dump all the crap baggage that Psychology has.) And Sociology and Economics are often little more than conjecture. There are far too many variables for either to control for, and yet we rely on them in court rooms, board rooms, and the oval office. These are the modern day ‘oracles’ abusing your trust in ‘science.’
Andrew:
You said: “The only reason one can know that homeopathy is a pseudo science and immunization is a useful medicinal weapon against disease is by knowing a bit of physics and biology.”
That’s a very, very narrow way of acquiring knowledge. It’s akin to saying, “If I’ve never been to China myself, I have no reliable reason for thinking it’s really there.”
If I know nothing of immunology (and I don’t have even a superficial acquaintance with the subject) I nevertheless have good reasons for believing that if 100,000 people get the H1N1 vaccine it’s better for that population (on balance) than if they didn’t get it. I can know that with as much confidence as I know, for example, that the large Hadron collider won’t eat the planet when it goes to full throttle up.
How do I know?
Because experts are unified on the issue and I know that they are basing their position on vigorous dialogue, reasons, and evidence.
It’s a heuristic, but it’s far more reliable than me going on the Internet and trying to figure out the value of H1N1 vaccination for myself (or whether the Hadron collider is dangerous).
I wish I was smarter than scientific communities as a whole, and could trust my judgment over theirs. But it is not rational to do this. Statistically, if I draw a conclusion different from the consensus of experts in a field, I am more likely wrong than right (even if I think my argument is, to my mind, air tight). You, Andrew, are reifying your own subjectivity in a way that might, in an 18th century Romantic sense, seem the assertion of individuality, but is, in fact, a means by which to increase your likelihood of basing your decisions on errors.
I’m not saying “don’t think, rely on heuristics.” I’m saying think, but give proper and principled (and due) weight (which should be high) to expert opinion (wherever that expert opinion is based in science).
I agree with you, of course, that there is no such thing as an expert in Freudian psychology or theology. These are not sciences. But once you’ve determined what is a science (or what is science within a discipline that may not otherwise be science in all respects), then expert opinion matters. And it matters a lot. This is not a deferring to “oracles.” It is a rational deferring to the Baconian disciplines guided by scientific inductions. You don’t blow off a team of medical experts when they say, “Get a flu shot.” And you don’t do this even if you don’t follow their reasoning for doing so—or perhaps even think it not terribly convincing in the way that they are explaining it in lay terms.
—Santi
Ignoring the China comment (which was a blatant straw man, really Santi we’re better than those kinds of arguments.) Experts NEED to be questioned. This is what frustrates me so much about the skeptical community. Whenever they come across a point that they disagree with they make a case for why its false based on evidence and reason. But give them an expert that they agree with and it’s arguments form authority all the way. If I make a bad call because I didn’t rust an expert when I should have, then I’ll suffer the consequences. I’m free to learn about a field without having to pay thousands of dollars to get a degree in the field, and if I come into disagreement with an ‘expert’ then it will be the evidence that decides the outcome not a diploma. Your insistence on valuing the credentials of others over your own mind is… well I find it very disturbing.
Andrew:
I would never say this: Don’t look at the evidence yourself, and don’t follow it to the full degree of your intellectual capacity. Of course you should. I do it all the time at this blog even though I don’t know what the hell I’m talking about half the time.
But it’s not you or me v. one expert. It’s you or me v. a whole field (if we are talking about a consensus of experts). One expert might well have no respect among his colleagues, or have bad motivations, or be crazy. I’m speaking statistically. Smart people with expertise who are using science should be given much greater weight than you are apportioning to them, especially when they are in consensus.
If you find yourself, for example, concluding, after an involved self-initiated research project of a year, that Earth is 10,000 years old, or that anthropogenic activity does not account for global warming, or that the Hadron Collider will make a black hole that will eat the planet, then you are not done. You need to find out what experts say. And if you find experts in overwhelming disagreement with you, it is grounds for you to deeply doubt your year-built opinion, and have a low degree of confidence in its conclusion. It is not grounds for blowing off expert opinion. Statistically, you are far more likely wrong than right.
Expert appeal is not authority appeal (at least not to my mind). It is, instead, an important step in rational inquiry (to make expert opinion important, and apportion my own beliefs, not just to evidence as I understand it, but to evidence as experts in a specialized field understand it).
If, for example, I think that there is life on Venus, and I find that experts overwhelmingly disagree, it’s time for me to reconsider my opinion, and hold it very, very tentatively. It’s not time for me to roll my eyes and talk of scientific priesthoods.
And give me one example of an expert scientific claim (in which consensus among the experts is high) that you think, as a lay person, you should dismiss as almost certainly wrong. Skip global warming, please. I really don’t want to go there. Give me a different example.
I doubt you can offer a reasonable one.
—Santi