Trusting Experts

Over on the Google+, Robin Hanson asks a leading question:

Explain why people shouldn’t try to form their own physics opinions, but instead accept the judgements of expert physicists, but they should try to form their own opinions on economic policy, and not just accept expert opinion there.

(I suspect the thing he wants me to explain is not something he thinks is actually true.)

There are two aspects to this question, the hard part and the much-harder part. The hard part is the literal reading, comparing the levels of trust accorded to economists (and presumably also political scientists or sociologists) to the level accorded to physicists (and presumably also chemists or biologists). Why do we — or should we — accept the judgements of natural scientists more readily than those of social scientists?

Although that’s not an easy question, the basic point is not difficult to figure out: in the public imagination, natural scientists have figured out a lot more reliable and non-obvious things about the world, compared to what non-experts would guess, than social scientists have. The insights of quantum mechanics and relativity are not things that most of us can even think sensibly about without quite a bit of background study. Social scientists, meanwhile, talk about things most people are relatively familiar with. The ratio of “things that have been discovered by this discipline” to “things I could have figured out for myself” just seems much larger in natural science than in social science.

Then we stir in the matter of consensus. On the very basics of their fields (the Big Bang model, electromagnetism, natural selection), almost all natural scientists are in agreement. Social scientists seem to have trouble agreeing on the very foundations of their fields. If we cut taxes, will revenue go up or down? Does the death penalty deter crime or not? For many people, a lack of consensus gives them license to trust their own judgment as much as that of the experts. To put it another way: if we talked more about the bedrock principles of the field on which all experts agreed, and less about the contentious applications of detailed models to the real world, the public would likely be more ready to accept experts’ opinions.

None of which is to say that social scientists are less capable or knowledgable about their fields than natural scientists. Their fields are much harder! Where “hard” characterizes the difficulty of coming up with models that accurately capture important features of reality. Physics is the easiest subject of all, which is why we know enormously more about it than any other science. The social sciences deal with fantastically more complicated subjects, about which it’s very naturally more difficult to make definitive statements, especially statements that represent counterintuitive discoveries. The esoteric knowledge that social scientists undoubtedly possess, therefore, doesn’t translate directly into actionable understanding of the world, in the same way that physicists are able to help get a spacecraft to the moon.

There is a final point that is much trickier: political inclinations and other non-epistemic factors color our social-scientific judgments, for experts as well as for novices. On a liberal/conservative axis, most sociologists are to the left of most economists. (Training as an economist allegedly makes people more selfish, but there are complicated questions of causation there.) Or more basically, social scientists will often approach real-world problems from the point of view of their specific discipline, in contrast with a broader view that the non-expert might find more relevant. (Let’s say the death penalty does deter crime; is it still permissible on moral grounds?) Natural scientists are blissfully free from this source of bias, at least most of the time. Evolution would be the obvious counterexample.

The more difficult question is much more interesting: when should, in completely general terms, a non-expert simply place trust in the judgment of an expert? I don’t have a very good answer to that one.

I am a strong believer that good reasons, arguments, and evidence are what matter, not credentials. So the short answer to “when should we trust an expert simply because they are an expert?” is “never.” We should always ask for reasons before we place trust. Hannes Alfvén was a respected Nobel-prizewinning physicist; but his ideas about cosmology were completely loopy, and there was no reason for anyone to trust them. An interested outsider might verify that essentially no working cosmologists bought into his model.

But a “good reason” might reasonably take the form “look, this is very complicated and would take pages of math to make explicit, but you see that I’ve been doing this for a long time and have the respect of my peer group, which has a long track record of being right about these issues, so I’m asking you to go along this time.” In the real world we don’t have anything like the time and resources to become experts in every interesting field, so some degree of trust is simply necessary. When deciding where to place that trust, we rely on a number of factors, mostly involving the track record of the group to which the purported expert belongs, if not the individual experts themselves.

So my advice to economists who want more respect from the outside world would be: make it much more clear to the non-expert public that you have a reliable, agreed-upon set of non-obvious discoveries that your field has made about the world. People have tried to lay out such discoveries, of course — but upon closer inspection they don’t quite measure up to Newton’s Laws in terms of reliability and usefulness.

Social scientists are just as smart and knowledgable as natural scientists, and certainly have a tougher job. But trust among non-experts isn’t demanded, and shouldn’t be based on credentials; it is given on the basis of a long track record of very visible success. Everyone would be in favor of that.

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77 Responses to Trusting Experts

  1. Greg Ransom says:

    “a reliable, agreed-upon set of non-obvious discoveries”

    1. It is impossible to “control prices” — “controls” merely increase costs & shift them elsewhere, block communication signals, and cripple the discovery process of competition.

    2. it is impossible in advance to know where rivalry and competition will take you; it is similarly impossible to advance into the unknown without the use of the discovery procedure of rivalry and competition, where each is allowed to explore his own unfolding understanding of local conditions in coordination with others via price signals.

    3. It is impossible to control the price of interest, the stock and velocity of money, and the degree of leverage and liquidity in the extended economy without distorting the coordination of economic plans over time in a fashion which will leave many inputs to production “out of work” when time reveals an unsustainable pattern of production plans.

  2. Greg Ransom says:

    Could there be anything more useful than to know what causes economic cycles — and what needs to be avoided in order to not to create massively destructive cycles?

  3. There’s a much simpler explanation: ordinary people don’t trust scientists; they trust engineers. Physics and the other hard sciences have long, successful engineering histories associated with them, so they get lots of trust. Biology and medicine have slightly less engineering, and therefore slightly less trust. Economics only has finance as its companion engineering discipline, and the success of finance is less than stellar. As for the social sciences–there ain’t no stinkin’ engineering, and therefore there ain’t no stinkin’ trust, either.

    This is, IMO, the main problem that climate science is having right now. They have some results, but there’s absolutely nothing they can engineer to make things better (or at least better enough to warrant the cost), so the public remains skeptical.

  4. Bee says:

    The problem is that in the public’s eye economic models mix with economic opinion. The first is what (ideally) can scientifically be stated, the second is the question what you want to do with that knowledge.

  5. kitov says:

    People do trust physics and physicists in every day activity. Aircrafts, ships, buildings in seismic zones, TV, mobile telephony, etc. is the material realization of scientific knowledge.
    New horizons in physics are not for the broader audience and do not have robust realizations yet.

    Theoretical macroeconomics (I do not include micro, finances, business, etc.) is a science without actual realizations when one can foresee important outcome. (We foresee that our airplane will land with a very high probability. Otherwise we would never use it.) Some physicists propose a scientific revolution in economics (Bouchaud, J.-P., (2008). Economics needs scientific revolution, Nature, v.455, 30 October 2008) . I would start with a simple data analysis in line with classical mechanics (Ivan O. Kitov, 2009.
    “Does economics need a scientific revolution?,”
    Quantitative Finance Papers 0904.0729,
    Actually, economic data do not match even basic requirements of physics. They are usually incompatible over time. One needs lots of patience to recover major time series like inflation, GDP per capita, rate of unemployment, etc. (

  6. You are correct to bring up the issue of political inclinations and ideologies having more of an impact on the social sciences. However, I think that you underestimate the importance of this aspect. I would suggest that the actual problem is almost completely due to political ideologies interfering. The strongest evidence for that is that there are areas of the hard sciences where people reject the science simply due to their religious or political leanings. Evolution and global warming would be the two most prominent examples.

  7. chris says:

    that’s an easy one.

    while in physics there are clear answers to clear questions, in economics the guess of the average layman is as good as that of the last nobel laureate.

    just as an example: i once saw the correlation between the 2-year prognosis for gdp growth vs. the actual growth. the correlation was actually negative 🙂

  8. Alex D says:

    It’s all about error bars 😀

    In physics, the Standard Model + General Relativity account for ALL observed experimental data with only a handful of model parameters. Perfect predictions, zero error bars.

    In economics, there is no theory analogous to the standard model of physics. Candidate macro- and micro-economic theories have modest predictive power at best. Therefore, none of those theories are “right” and are at best approximations of a full and correct theory (assuming one exists). Poor predictions, large error bars.

    The original question was: “Explain why people shouldn’t try to form their own physics opinions, but instead accept the judgements of expert physicists, but they should try to form their own opinions on economic policy, and not just accept expert opinion there.”

    My answer is that people are free to form whatever opinions they like, but probably shouldn’t feel the need to try to improve upon a physical theory which has perfect predictive power. It’s more reasonable to want to form your own opinion about economics because it’s a subject in which models and expert opinions have poor predictive power = big error bars! I’m not saying that it’s easy to come up with a better economic theory, only that it’s natural to find the existing theories lacking.

  9. bs says:

    Explain why people should reject predictions of soothsayers and astrologers out of hand, and not reject judgements of expert economists in the same way.

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  11. Greg Ransom says:

    In Darwinian biology there is no theory analogous to the standard model of physics, ditto a dozen other powerful explanatory domains within science.

    So what?

    “In economics, there is no theory analogous to the standard model of physics.”

  12. Greg Ransom says:

    The biggest problem isn’t that there has been massive explanatory success in economics, providing lessons for mankind of the most signal importance: the names Mises & Hayek come to mind.

    The big problem is how much fake science is produced by tenured professors within economics department attempting incompetently to imitate very tiny slices of what is done in the math & physics department — all while attempting satisfying the philosophical demands of failed philosophical projects from generations ago. See on this particularly the work of Friedrich Hayek, Bruce Caldwell & Philip Mirowski, among many others.

    The word “scientism” was coined by Hayek to capture this epic FAIL by the tenured professors in the economic departments.

  13. Low Math, Meekly Interacting says:

    I think I have a good metaphor to illustrate my skepticism and concern about economics (the field as a whole): Everyone needs to assume the spherical cow from time to time. The problem with economists is that, once the cow has been show to be non-trivailly aspherical, they proceed to tell us that obviously real cows must have been ruined by cultivation, and then, as a group, provide a litany of often mutually-exclusive remedies to bovine asphericity.

  14. Lots of people distrust physicists. We can start with anti-nuclear-power activists and continue through young-Earth creationists, astrologers, people who think that quantum mechanics means that refusing to perceive something means it doesn’t exist, etc….

    Have you ever tried telling a liberal activist that depleted uranium is relatively harmless?

  15. Barry says:

    @28 The Radical Moderate:

    “This is, IMO, the main problem that climate science is having right now. They have some results, but there’s absolutely nothing they can engineer to make things better (or at least better enough to warrant the cost), so the public remains skeptical.”

    No, the main problem that climate science is having is a lavishly funded campaign of lies and fraud.

    However, your point on trusting engineering, not science per se, is great.

  16. Charlie says:

    But plasma cosmology must be true. Why else would all the “experts” deny it?

  17. Len Ornstein says:

    Building models requires consistent use of agreed upon axiomatics; that is, definitions of fundamental terminology and the equivalent of syntactic and grammatical rules, in order that they will be similarly perceived by participants in a ‘discussion’ of their usefulness.

    Scientific models (ideas, speculations, theories and ‘Laws of Nature’) depend upon consistency with such agreed upon foundations. And science ALSO requires that predictions/projections of models are supported by empirical ‘observations’ of ‘reality’. The more pertinent, the more unbiased and the more frequent the support, the higher the confidence in the model.

    The models of mathematics, religions and numerous other disciplines also supposedly require ‘faith in’ their axiomatics and consistency in their application. But they usually do not require empirical confirmation.

    For example, “demand side” and “supply side” economics have different axiomatics – and no consistent empirical support for the predictions of either – in fact, many horrendous failures! They are more nearly dogmatic ideologies than ‘science’. That’s the main reason their experts should not be trusted.

    In scientific fields, where models have received empirical support at high levels of confidence – which can usually be witnessed by a high level of consensus among the specialists in those fields – experts may be worth trusting.

    Obviously, IF one knows enough about the axiomatics, the models and/or their empirical ‘record’, you may not need to rely on expert opinion.

  18. Olli Pehkonen says:

    Economics can be said to have been slow to make progress compared to, say, physics in the last century or so. You should however keep in mind that some progress has been made. If you look at the great depression in the 30ies you will see that unemployment rates in the USA were around 20%, where in this crisis the rates are around 10%. One of the reasons is what we have learned from economics.

    The idea of a balanced budget (ironically being debated in USA politics) should be applied only over a longer period than a fiscal year, maybe even longer than a decade. During the great depression the US goverment tried to keep a balanced budget and thus deepened the depression. This happened because when there is less economic activity, there are less taxes paid. If the government tries then to keep a balanced budget, they will have to also cut down on spending, causing more people to lose jobs, less taxes again, less government spending again, less jobs again…

    We understand this now and thus are not likely to experience recessions as deep as the great depression anymore, at least not due to the business cycle. There are important lessons that have been learned in economics too, just they tend to come slowly.

  19. ezra colbert says:

    Ask yourself: how passionate am I, personally, about
    the mass of the proton
    role of quarks as constituents for protons

    we are descended from monkies
    sex ed decreases sexual activity in teens

    I think one thing we do learn from psychologists is that people disregard facts if the facts conflict with beliefs; since most of us don’t have, or don’t care that much about the mass of the proton, there is no problem with accepting experts.

    Also, the “hard” scientists are probably better at hiding their errors; I mean, someone publishs a math heavy paper on proton mass that is wrong, it is not exactly front page news….

  20. Jim Harrison says:

    Economics is more like formal linguistics than physics. It depends on a mostly theatrical show of mathematical rigor to distinguish itself from the rest of sociology just as the generative grammar folks of the 60s made a big deal out of tree diagrams and other paraphernalia to impress the natives. Empirical confirmation? No so much. That doesn’t mean that economists don’t have some valuable ideas, just that the state of economics as a whole is rather like what we’d be dealing with if astronomy and astrology were still just one subject.

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  22. Chris says:

    One quibble: social science theorists do consider moral issues. My girlfriend is a political theorist (Department of Political Science) and her candidacy reading list ranged from Plato and Aristotle through to Hobbes, Locke, and Hume, and on to Mill, Nietzsche and Rawls. A good social science theorist will tackle questions to which, in principle, there are no correct answers.

    In other words, proper social science is not all just sociological and economical phenomenology, fields in which there presumably are true/false answers regarding causation. Even model-makers in these true/false fields need abstract concepts like Identity or Utility, and no one contends that these things are “out there in the world” in the way that we physicists convincingly interpret out abstract theoretical entities.) So we probably shouldn’t insist that the success or failure of all lines of social-scientific inquiry be decided solely or even at all by number of “things that have been discovered” or consensus among practitioners.

    (Then why call them a science? That’s an active-ish debate within the social sciences themselves, although as opposed to the humanities even interesting ideas are ideally dropped if they don’t “work” or have explanatory power – a bare-bones scientific method.)

  23. Gizelle Janine says:

    I agree/disagree on too many levels to mention but…

    I think the question in general enraged me quite a bit in regards to science, specifically I thought about what theory happens to be, and generally what the scientifc method is. I dont know I could be brain dead and not know it.

    Great post. 😀

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