Good science, wrong answer

Sometimes it happens that somebody does good science, but has arrived at a wrong answer. Since most of us think that the answer has to be right (and I'll agree that it's better when it is), this will take some explaining. Let's go back to what science is about -- trying to understand the universe in ways that can be shared. Good science, then, is something that leads to us understanding more about the universe.

For my illustration, I'll go back to something now less controversial than climate. In the 1980s, paleontologists David Raup and J. J. Sepkoski advanced the idea that mass extinctions, such as the one that clobbered the dinosaurs, were periodic. Approximately every 26 million years, for the last about 250 million years, they observed a spike in the extinction rate. Not all were as large as the one that got the dinosaurs.

It so happened that they were at the University of Chicago, in the Department of Geophysical Sciences, and so was I. Further, I was working with time series for my master's thesis. So I asked them about working with their data and seeing what I would find with my very different approach. They were gracious and spent some time explaining what I was looking at, knowing that I didn't think they were right. By my approach, indeed, their idea did not stand. My approach, however, was not a strong one, being susceptible to some important errors. So I never published about it. Still, along the way, I learned more both about time series, and about paleontological data. So that's a plus making the periodic extinction idea 'good science' -- I, at least, learned more about the universe, even if not enough to make original contribution.

One mark of good science is that it prompts further research. Raup and Sepkoski, in their original paper, had made a reasonable case. 'reasonable' being that it could not be shot down by any simple means. 'simple' meaning that the answer was already in the scientific literature. So to knock down the case, itself a normal process in science, the critics had to do some research to show how weaknesses or errors in one or more of the following lead to the erroneous conclusion:
* The statistical methods
* The geological time scale
* The paleontological data (extinction figures, and their dating)

The idea was not sensitive to the geological time scale used, so that fell away fairly quickly. The statistical methods did develop a longer-lasting discussion -- new ones devleoped, flaws in the new and the old methods described (and then discussion about whether the claimed flaws were real).

Most interesting to me, and I think where the greatest good for the science was, was going back to the data. In saying that the extinctions were periodic, one carried the image of something crashing into the earth (like the meteor that did in the dinosaurs) and killing off huge numbers of species (and genera, and families) very quickly. One of the data problems, then, was getting accurate dates for the time of extinction. Often the data could only say that the things went extinct sometime within a several million year window. That's a problem, as then your view of whether it was periodic could depend on whether you put the date of extinction at one end of the geological period or another. So people went to work on getting better dates for when the species went extinct.

Also, I noted above that the original idea applied to the last 250 million years. The reason was, when they started that was as far back as you could go with reasonable data. So work also went in to trying to push back the period of reasonable data.

I don't know what the field ultimately concluded about the idea. I do know that the work to advance or refute the idea resulted in more data about when species went extinct, and better dates for when they did. Further, those newer and better data are themselves useful for learning more about the universe -- there's more to be gained than just answering the original question about whether mass extinctions were periodic.

So, not only did the original publication result in more being learned about the universe, but it was in a way that enables even more learning to happen. That makes it good science. The original idea might have been wrong, but it definitely was good science.

I've focused on the side of scientific merit here. There was a lot of, well, unprofessional, response as well. You can read about both parts in The Nemesis Affair: A Story of the Death of Dinosaurs and the Ways of Science by David Raup. Part of it was because the idea that any mass extinction had to do with things crashing in to the earth was still new, and still widely not accepted. Then this idea comes up and says that not only does it happen (bad enough) but it had happened many times, and happens regularly.