Argument from Authority vs. Trusting Experts

Some folks who argue against anthropogenic climate change argue that folks like me who accept the evidence that it's happening and it's something we should worry about are guilty of bad science. Specifically, that we're accepting arguments from authority, rather than evaluating the evidence.

While argument from authority works in some lines of reasoning, it's anathema to science. Science usually proceeds by starting from a set of assumptions or postulates, and seeing what results-- but those assumptions and postulates are always subject to test, and if experiment or observations show that they're wrong, they have to be tossed out. We believe something is true in science because the experiments or observations have show it to be true, not because some designated authority has asserted that this is how things are.

However, if you perform reducto ad absurdum on this argument, most of us have no right to accept the vast majority of the scientific knowledge that the human race has amassed. Have you, personally, verified Einstein's theory of Special Relativity? OK, I have seen the moons of Jupiter making their way around Jupiter, so I've confirmed Galileo's observation disproving Geocentricity... but have you? And if you haven't... what right do you have to assert to Geocentrists that they're full of it, and that the center of mass of the Solar System is really close to the Sun? Huh? Huh?

Over at the RealClimate blog, a guest commentary by Anderegg et al. make this point in a way that struck me as rather nice:

We accept and rely upon the judgment and opinions of experts in many areas of our lives. We seek out lawyers with specific expertise relevant to the situation; we trust the pronouncement of well-trained airplane mechanics that the plane is fit to fly. Indeed, the more technical the subject area, the more we rely on experts. Very few of us have the technical ability or time to read all of the primary literature on each cancer treatment’s biology, outcome probabilities, side-effects, interactions with other treatments, and thus we follow the advice of oncologists. We trust the aggregate knowledge of experts – what do 97% of oncologists think about this cancer treatment – more than that of any single expert. And we recognize the importance of relevant expertise – the opinion of vocal cardiologists matters much less in picking a cancer treatment than does that of oncologists.

They don't even reducto to as absurdum a point as I did-- whereas I was talking about replicating the experiments yourself, they're just talking about reading the primary literature. Of course, in reading the primary literature, you're already taking some things on faith. (Little-f faith, not big-f Faith.) Specifically, you're trusting the ethics and competence of the investigators who performed and confirmed the experiments. You're trusting that it's not one big collusion and conspiracy amongst the writers of the primary literature to promulgate a falsehood on the rest of the world.

We do that constantly, every day, and it's only rational to do that. This includes climate change. The vast majority of people who know anything about climate change are convinced about the existence of anthropogenic climate change, and that it's a problem. The details and the severity of the problem remain under debate of course, but the consensus that there's something to worry about is very strong. Accepting and acting on their expertise is not resorting to an argument from authority; it's just trusting the experts to know their field of expertise. Saying that we shouldn't advocate national and global response to the problem of global warming without each of us individually verifying the evidence ourselves is tantamount to saying that it is unwise to get on an airplane without learning enough to verify the mechanical fitness of the plane first.

5 responses so far

  • Mary says:

    When I used to TA the freshman physics labs, I would tell the students that the reason they were doing these labs was because otherwise they would have no reason to believe in Newton's laws. Their prof told them F=ma. But he or she didn't prove it. We can't prove it, actually. The only reason we believe it is that it corresponds to experiment. Since they're studying science, they shouldn't take their prof's word. They should do their own experiments, and be convinced for themselves that these unprovable statements actually correspond with reality.

    Then, of course, when people would get ridiculous lab results, they would always write in their conclusions that they had "disproved Newton's laws." I would congratulate them on the scientific revolution they were about to cause, once they had verified those results. 🙂

  • rknop says:

    Mary -- let me guess, when you said they had to verify the results they accused you of "moving the goalposts"? 🙂

  • Claus says:

    I can't quite accept your argument - at least not all of it. There are lots of 'climate skeptics' who are skeptical of anthropogenic global warming based on science, and most do not dispute the fact that there is such a thing as the Greenhouse Effect - this can be proven in a lab, and is verified scientifically. Disputing this would - as you say - be tantamount to disputing the Theory of Relativity, Newton's Laws, etc.

    Climate change science is something totally different. The first reason is that climate science is in its infancy, as climate is notoriously difficult to predict at the best of times, particularly since it's not about one or two 'laws of physics', but an incredibly complicated interaction of many, many factors, many of which are not well understood (the impact of solar radiation, etc.).

    Think about it in terms of practical science: Climate change scientists claim that a nearly infinitesimal change in CO2 concentration - on the order of a few hundredths of a percent of the atmosphere by weight - over a very long time - say 20-30 years - is likely to cause another very small change in global temperature. You think the margin of error in such a calculation is huge? Any properly trained scientist would say yes. Still the IPCC says the probability is 90%. I just cannot believe that.

    • rknop says:

      Claus -- "any properly trained scientist" would say yes? And, yet, somehow, the vast, vast majority of the trained scientists who are trained in that field agree that the predictions are robust. Who am I going to believe, the vast majority of people who've spent their lives working on this, or you with your assertion that "numbers are small"? That's the point of my post - do I really know how all the CO2 stuff works? No. But there are people who do, and they are all saying the same thing.

      Check this link out:

      Global warming based on CO2 was predicted before the current strong trend, and **while the yearly temperatures were flat or slightly cooling**, based on this science.

      Your argument of tiny changes could be used to demolish cosmological Inflation. A change of a tiny fraction in the density of the Universe would have meant that the early Universe recollapsed before galaxies had a chance to form, or that the Universe would have expanded so fast that galaxies wouldn't have been able to form. Based on this, theoretical cosmologists told us for years that the total density of the Universe was the critical density, even though observers, even with dark matter, could only find a quarter of that. Now, not only do we know that the total density is about the critical density, we also have independent confirmation of the inflation paradigm. Yet... because one part of the argument for it required just a tiny change, would "any properly trained scientist" say that the margin of error was huge and thus we shouldn't put any stock in it?

    • rknop says:

      Also, by the way -- we're certainly *not* talking about an infinitesimal increase! If you find the classic "hockey stick" CO2 diagram (*), and read the vertical axis, you can see that the CO2 concentration *today* is about 380ppm, and the highest it ever was in recorded history was about 280ppm. A 30-40% increase doesn't fit anybody's definition of infinitesimal.

      * For instance, look here :