16 December 2008

Science and consensus

Sometimes people are right about a statement and then draw the wrong conclusion about it. Noting that science doesn't 'do' consensus is such a case. By the time you've progressed to the point of general agreement -- and all a consensus is is general agreement, not universal agreement -- the point has dropped out of being live science.

The science is in the parts we don't understand well. That's effectively part of the definition for doing science. Dropping two rocks of different mass off the side of a building and seeing which one hits the ground first is no longer science. We reached consensus on that some time back. Now if you have a new experiment which tests something interesting (i.e., we haven't tested that one to death already), have at it and do that science.

I didn't appreciate it properly at the time, but a sign on the chemistry department door in my college put it best: "If we knew what we were doing, it wouldn't be science." The live part of science involves learning new things. If you already know what will happen, you're not learning new things so aren't doing science. After you've learned something new, and others have tested it and confirmed your learning, then we have a piece of scientific knowledge. It isn't live science any more, but it's a contribution to the world and can be used for other things. A consequence of this is that you wind up knowing a lot if you stay active in doing science. But it isn't the knowing that motivates scientists (certainly not me) it is the finding out new things about the world.

So we have two sides to science -- the live science, where you don't have consensus -- and the consensus, the body of scientific knowledge that can be used for other things (engineering, decision making, ...). The error made by the people who try to deny, for example, the conclusions of the IPCC reports because 'science doesn't do consensus' is that they're confusing the two sides. The live science, which is summarized in the IPCC reports, doesn't have consensus. That's why it's live and why folks have science to do in the area. The body of scientific knowledge, which is also summarized in the reports, does have a consensus, which is being described in detail as to what the consensus is about and how strong it is.

It is possible that the consensus is wrong in its conclusions. But the folks denying it need not only for it to be wrong, but to be wrong in a very specific way. If they wanted to make scientific arguments, which is what, say, Wegener did in advancing continental drift in the 1920s, they can do so. But it is their responsibility to make the arguments scientifically and back them with strong scientific evidence, as Wegener himself noted. They don't do that.

I'll follow up the matter of the consensus having to be wrong in a specific way in a different note or two at a later date.


Philip H. said...

Again, a great post. I'll add a specific link to it shortly from my place.

Hope you won't mind, but I may lift an idea or two from you in future talks I give on science and climate.

Robert Grumbine said...

Thanks again kcsphil.

Ideas are for sharing. If any of mine look useful, by all means put them to work. Let me know how they go if any have particularly good or bad results. Since you're in the area, if you're talking to a public audience on the Maryland side, let me know.

John Mashey said...

re: Wegener & co

I recommend Naomi Oreskes' book "The Rejection of Continental Drift: Theory and Method in American Earth Science", about which here are a few comments.

Robert Grumbine said...

Thanks for the reference. Looks like I was beaten to the writing of another book.

The regionally variable degree of rejection of drift has been a topic of interest since I read Wegener in the first place. He did also make a few significant (I think) mistakes, not least being that he wasn't 'radical' enough to accept radio-dating. That would have cleaned up some of his problems. It wasn't an old idea at the time, but it also wasn't very new and untested.

Robert Grumbine said...

Let me add: If you haven't already read John's full post at the top of his link, go up to the top and do so. It's from August, titled 'How to Learn About Science', a topic near and dear.

Anonymous said...

You have achieved a great explanation! This is excellent material that should be brought on tap when in combat with deniers and delayers who just love to talk about the UN IPCC confabulating to spread painful restrictions on free markets. They do this by saying that the IPCC is a dark conspiracy, fed by $$$ millions from Planet Gore, or some such drivel, from those freedom haters seeking world government. For those few arguments with deniers possessing a semblance of a brain, your cogent distinction between live science and consensus science is brilliant! Thanks.