Could you give me some cites for that? I’d be curious to see how people felt about heliocentrism back then.
Do you think that such situations have ever arisen?
He was THE true Scotsman.
The actual point of my comment was that the number of folks who subscribe to a theory does not in and of itself mean that the theory is valid or invalid.
That’s all.
Sure. You’ll have to excuse my quoting a printed rather than online source; as a historian of pre-modern science, I’m more familiar with what’s in my own library than with what’s available and trustworthy on the web when it comes to this field. From The Copernican Revolution by Thomas S. Kuhn (best known for his seminal work The Structure of Scientific Revolutions, Harvard University Press, 1957:
Sure, but AFAICT, at least in modern science they have tended to be a pretty unstable equilibrium. The “entrenched scientific establishment”, though it certainly exists and certainly does sometimes resist valid new ideas, is nonetheless very permeable to them, and usually can’t keep them out (even if it tries to) for more than a few years at most.
Off the top of my head, I cannot think of an example within about the last century where a substantial or overwhelming majority of world-wide practitioners of a particular scientific discipline agreed in provisionally adopting and substantially developing an invalid or unjustified hypothesis while professionally repressing skeptics who criticized it, and kept following this false trail for as long as twenty years or more.
That is pretty much what the climate skeptics are claiming that mainstream climate science researchers have been doing. I think such a situation would really be quite exceptional in modern science, and I would need to see some pretty conclusive evidence to believe that those claims are correct.
I understand, but it would be interesting to know if situations have arisen in the past where the scientific consensus (whatever that means) was dead wrong.
Thank you.
Here’s a quote from Michael Crichton. While I wouldn’t be surprised if he’s exaggerating, he does make it seem as though the consensus can be wrong for quite a while:
Would you care to comment on his point?
In your opinion, when was the first year in which there was a conensus that AGW is real?
Crichton is abusing the word “consensus”.
One can argue quite a bit about why Semmelweis (to use the correct spelling) failed to convince people about his ideas. Thus in The Doctors’ Plague (Norton, 2003), Sherwin Nuland argues in some detail that the failure was largely Semmelweis’s fault: he misplayed the personal politics, his point didn’t seem either particularly original or clear, he was tardy in publishing his data, etc. It’s also not the case that Semmelweis found no allies - contrary to the usual myth, there was a significant minority of doctors, particularly in his immediate circle in Vienna, who were at least somewhat sympathetic to his suggestions.
However, the more fundamental point is there’s a difference between pretty much everybody rejecting one person’s ideas and that situation usefully being described as a “consensus” in the positive sense of the word.
Why? Other than the, in practice, largely incidental property of disagreeing with Semmelweis, the purported “consensus” had virtually nothing in common. They didn’t have a prevailing shared hypothesis about why puerperal fever occured. In other words, they disagreed as much amongst themselves as they did with Semmelweis.
Semmelweis wasn’t attacking a consensus. He was failing to convince a whole range of doctors who all had largely idiosyncratic - though undoubtedly often conservative and, in hindsight, wrong - reasons for believing differently.
[QUOTE=brazil84]
Thank you.
Would you care to comment on his point?
QUOTE]
I dont quite understand his point. There have been times when the consensus has been wrong for centuries obviously, in that we learn new things, that correct previous positions, and sometimes minority positions dont gain sway for quite some time, even when correct.
Is he saying we should ignore the consensus then? And if so what would we replace that with? Noones arguing peer review is a perfect process, simply that a better one hasnt really been developed yet. Focussing on the times its been wrong kind of ignores the many other times when its been correct.
Otara
Here’s what it says in the Wikipedia article on Semmelweis:
I imagine he would say that we should look at the actual science.
While I can readily believe that it still cropped up in the quack medicine - Roy Porter mentions a couple of 18th century English examples in his excellent Quacks (1989; Tempus, 2003) - and popular culture of the day, I’m seriously not convinced that any major European medical school was exclusively, or even seriously, teaching humoral theory in the 1840s. Its influence arguably still lingered, but that’s not the same.
Unless you can come up with a better cite, chalk that up as an example of Wikipedia sometimes being shite.
As Blake and intention have pointed out, we actually know that it goes both ways. It is true that our current “experiment” is different from the previous ones in that in this one we are increasing the CO2 levels rapidly by ourselves. During the previous times, it is understood that orbital oscillations (see here) are the triggers for warming and cooling periods and that the CO2 levels then change presumably due to release or absorption of CO2 from the oceans (and possibly some land sources and sinks too). [And, note that the time scale over which this happens is much more slowly than the rate at which we are increasing CO2 today. In fact, the lag time of ~800 years corresponds to roughly a time it takes to mix deep ocean waters up to the surface.]
However, it is also known that CO2 is a greenhouse gas that causes a radiative forcing of about 3.7 W/m^2 for each doubling of CO2 levels. The best estimates are that CO2 accounts for something like 1/3 of the warming during an glacial-interglacial cycle. Note that we can, as James Hansen has done, estimate all the known major contributions to radiative forcing going from the ice age to interglacial and compare that to the temperature rise and thus get an estimate of the climate sensitivity…that is, how much warming occurs due to a given radiative forcing. This estimate gives about 3 C of warming for a doubling of CO2, in agreement with estimates from climate models. (Admittedly, there are decent-sized error bars on both estimates…but in order to, say, cut this estimate in half, it would be necessary to revise down the estimate of the warming out of an ice age or revise up the estimate of the forcings such that the ratio of the two decreased by a factor of 2, which seems pretty unlikely.)
If your professor believes this then frankly he is just whacked. The measurements of CO2 levels are now made at several stations around the world. (And, the ice cores provide records going back further in time.) There is no doubt whatsoever that we are causing (almost all of) the current rise in CO2 levels!
I’m not sure what this means. What is true is that it is not correct to simply superimpose the graphs of CO2 and temperature going back through the last several ice age - interglacial cycles in order to predict what temperature a certain CO2 level will correspond to. This is because, as I noted, CO2 was responsible for only part of the warming from the ice age to the interglacials. Also, temperature depends approximately logarithmically on CO2 level, not linearly.
Well, I don’t really know how to respond to this claim except to say that it seems rather unlikely in light of the strong evidence that the current warming (since the middle of the twentieth century) is not natural.
First of all, the idea that the inter-oceanic conveyer belt is likely to halt at least over the next century is now considered to be quite unlikely although it may slow down somewhat. Second of all, this would not drastically cool the planet as a whole. It would only cool certain areas and the current thinking is that it would not cool them as much as was once thought.
Unfortunately, although many non-scientists want to see a definitive “smoking gun”, the fact is that science seldom works this way. What we have is a wide array of evidence that points to it being anthropogenic (which you can read by delving into the full IPCC reports) and little or no evidence that it is natural (despite the fact that there are powerful interests who would like to show that it is natural).
This is why not only has the IPCC concluded that AGW is real, but this conclusion has been supported by a variety of other important scientific organizations. For example, see this recent statement by the U.S. National Academy of Sciences and the analogous bodies in 10 other major countries. The NAS is specifically chartered to advise the U.S. government on scientific issues that have policy implications. You can find similar statements by the councils of the American Meteorological Society and the American Geophysical Union.
Furthermore, even many of those who have a strong motivation to fight the AGW hypothesis have given up in the face of the growing scientific evidence. For example, companies such as BP and Ford were once part of the Global Climate Coalition, an industry group whose purpose was to raise doubts about the science of AGW. Now that group has fallen apart and companies like BP, Shell, and Ford have accepted the basic science of AGW. And, even many power companies in the U.S. have started to call for the government to set caps on CO2 emissions.
First of all, your link is hardly an unbiased credible source. If you want to look at a balanced discussion of the “hockey stick”, see the NAS report on temperature reconstructions. (Note that you can read the whole thing online.)
On the basis of the “hockey stick”, the IPCC in its third assessment report made two statements about temperatures, one regarding the temperature in the last 20th century being the highest in a millenium and another regarding the rate of rise in temperature over the 20th century being the highest of any century over this period. Both of these statements were categorized as “likely”, which in IPCC lingo means they are estimated to have a greater than 66% probability of being correct (but less than 90%, which would qualify them for the category “very likely”). Neither of these statements has been shown to be wrong and, in fact, one of the two has been re-affirmed as likely in the IPCC’s most recent (fourth) assessment.
I hardly think that qualifies as any major sort of error. In fact, if all of the IPCC’s statements that they rank as “likely” turn out to be correct then they could be accused of vastly overestimating uncertainties!
Cite?
The ether maybe?
Thanks for your posts, intention, as you well know by now, I have a different view that I will elaborate on in response to your post.
The problem with such a “no regrets” approach is it really should be called the “no regrets for ExxonMobil and Western Fuels Association” approach since it is really based on looking at only actions that even they wouldn’t oppose (and doesn’t commit to actions that even many other fossil fuel and power companies now support!!). In fact, it is an approach that will lead to major regrets unless the vast majority of the scientific community turns out to be wrong. In other words, it is betting the farm on a long-shot. That is why the National Academy of Sciences and the other academies in their joint statement say:
In fact, most scientists, far from thinking that the remaining uncertainties justify inaction, would argue that they more strongly justify action. We are essentially performing an uncontrolled experiment on the only planet we have and, while there are still some significant uncertainties about what all the consequences will be, we do know enough to know that the perturbation we are making is significant and we are perturbing a climate system that the paleoclimate record has shown is “an angry beast” (to borrow a phrase).
The fact is that, while they may be statistically different (which is not at all surprising given the real issues the intention himself pointed out regarding data quality and how you assimilate it), they are in good agreement on the basic trends. I.e., it is a difference that really doesn’t amount to more than a hill of beans. And, unfortunately, this is a strategy of the “skeptic” crowd to make such mountains out of molehills because the product they are selling is uncertainty, just as the tobacco industry was a few decades ago. (There are in fact at least a few folks active in the skepticism on climate change who were active with the tobacco industry previous to this.)
What most people don’t realize is that in science there is never absolute certainty. In fact, here is a good book on the subject that helps to explode the myths around science that allow those who oppose scientific conclusions in a certain field to make it seem like the science in this field is somehow different…and more uncertain…than the rest of science.
How can a treaty that regulates emissions over a 5 year period (2008-2012) make a significant difference by itself? After all, even if we stopped emitting CO2 completely for 5 years and then went back to our previous ways, we would just delay the warming by about 5 years. This is a straw man. The purpose of Kyoto or other cap-and-trade or carbon tax approaches is to set us on a new path and to put a cost on using our atmosphere as a free dumping ground for CO2. Once you put a cost on something, market forces will push the necessary technological innovations that have to occur. The thing about markets is that they are really shitty at solving problems that are hidden from them and, without a direct cost associated with emitting CO2 into the atmosphere, the problem is hidden from the market.
The fact is that we are going to have to eventually invest in the innovations to get beyond fossil fuels simply because they are a finite resource. The only question is whether we do this before we cause significant damage to our environment or after.
Who should look at the actual science? Are you qualified to evaluate it? The people who are qualified to evaluate it and have come to the same conclusion, you dismiss as somehow being biased, no matter how well-qualified and reputable.
I’m a little bit puzzled by it, because he seems to be contradicting himself. He speaks of “the consensus”, but then asserts:
Which seems to imply that there wasn’t in fact a “consensus” opinion on the issue. (I’m also a little puzzled by Crichton’s apparent conflation of doctors and scientists. While doctors often do important work in the cause of science, I think there’s no question that the vast majority of practicing doctors are not scientific researchers, nor were they back in the 19th century. So I’m not sure we can use the history of medical practice to draw reliable conclusions about the phenomenon of “consensus” among scientific researchers.)
Either way, however, it doesn’t affect the point I was making. Certainly there have been mistaken scientific views in the past, and certainly at some points in the past mistaken scientific views have been dominant, or even (almost) unanimous, even among professional groups more or less corresponding to what we now call “scientists”.
But what I was saying is that I can think of of no instance within about the past century in which ** a substantial or overwhelming majority of the world’s practitioners of a particular scientific discipline** joined ranks to support an unjustified hypothesis and successfully repressed legitimate scientific criticism for a period of more than twenty years.
That is, we’re not just talking about a scientific position possibly being wrong here. Sure, the AGW hypothesis could possibly be wrong, just as any other scientific hypothesis possibly could.
But many AGW skeptics seem to be claiming much more than that. They appear to be claiming that the AGW hypothesis is not only possibly wrong, but that it’s somehow illegitimate as a consensus opinion. They seem to think that the AGW hypothesis has survived and flourished primarily because of scientific fraud, dishonesty, lack of transparency, and institutional and professional repression of opposing views.
And that seems to me like a pretty extraordinary claim. After all, the AGW hypothesis has gained ground to a huge extent over the past two or three decades, attaining increasing levels of scientific support and credibility over a wide range of scientific disciplines. Sure, it might still be wrong—that’s always possible with any scientific theory—but it still appears to be by far the best and most productive hypothesis that we’ve got on this issue.
But many skeptics seem to be arguing that the AGW hypothesis is not just wrong but actually bad science, irresponsible science that never deserved to become the mainstream position. In other words, they are alleging a massive institutional and procedural breakdown of global scientific practice that AFAICT is absolutely unprecedented over at least the past century.
The level and extent of bias, dishonesty, fraud, self-interest, institutional corruption, and just plain bad faith that they have to postulate among thousands of members of the research community all over the world in order to explain this is simply too immense to be plausible, IMHO.
Absolutely. Who do you think is qualified to evaluate the actual science?
I’m not sure I agree, but before we get into it, please answer my earlier question:
In your opinion, when was the first year in which there was a conensus that AGW is real?
The scientists in the field. It is interesting that you feel more qualified than I do to evaluate something that you seem to know much less about.