I told you so. For years, I have been arguing that scientists and science educators should stop talking about science as if it were possible to completely “prove” a hypothesis or theory. Instead, we should be MILITANTLY trying to get our students and the public to understand that science is always tentative, involves creativity, and so on. For example, I argued this point in a recent talk at DePauw University, a 2010 blog post, and a couple 2009 papers published in the Journal of Geoscience Education. Here’s a passage from one of the papers.

Scientists and science educators are often frustrated when their students or the general public reject certain scientific theories (e.g., evolution or climate change) without a proper hearing. We then complain that if people only understood the nature of science (NOS,) they wouldn’t be so militant in their resistance. This is true, but much of the fault lies with us. Science educators often either neglect to teach the NOS, or hold to outdated views and pass them on to students. If we hold more sophisticated views of the NOS, we often soft-pedal the creative and tentative aspects of scientific thought, out of fear that students will take this as license to reject science outright. (Bickmore et al., 2009, On teaching the nature of science and the science-religion interface, Journal of Geoscience Education, 57, 168-177.)

Now, a recent case in point. On the “Somewhat Reasonable [sic]” blog of the discredited Heartland Institute, James Trzupek reported his astonishment at a comment about the nature of science by climate scientist Michael Mann. Here’s how Trzupek begins.

In a post over at Peter Guest’s blog, Michael “Hockey Stick” Mann is quoted making one of the most remarkable statements that I’ve ever heard coming out of a supposed scientist’s mouth: “Proof is for mathematical theorems and alcoholic beverages. It’s not for science.” He goes on to explain that science is all about “credible theories” and “best explanations” and his gosh-darn critics supposedly don’t offer up any of those. Now it seems pretty obvious that Mann’s attempt to separate proof from science stems from increasing public awareness that the warming predicted by the high-sensitivity models that Mann and others have championed just hasn’t occurred over the last fifteen years. No matter. You don’t need “proof” when you have “credible theories.” That comes as something of a shock to me. When I was going to school to earn my degree in chemistry, we were taught that science was indeed all about absolute truths and proofs at the end of the day. “Credible theories” is how you got to those truths, not an alternative to them.

Mr. Trzupek’s comments seem to show an astonishing ignorance about the nature of science that could be cured by taking a single course in the History and Philosophy of Science or reading a single textbook on the subject. My recommendation for the beginner would be Samir Okasha’s Philosophy of Science: A Very Short Introduction, but if you don’t want to spend the time to read Okasha’s 160 pages, I wrote a 15 page piece on the subject for introductory science students called “Science As Storytelling“.

The idea that scientific theories (or any other kind of theories) are always “underdetermined” by the data has been around at least since David Hume in the 18th century, but since the last half of the 20th century it has been the standard position among historians and philosophers of science. E.g., even back in 1934 Karl Popper could write (in Logik der Forschung) that scientific theories are “forever tentative,” because they can never be conclusively proven true, but he clung to the idea that at least they can be “falsified,” i.e., conclusively proven false. Subsequent scholars like Imre Lakatos and Thomas Kuhn employed very strong historical and philosophical arguments to show that even Popper’s falsifiability criterion was too strong. Now, a standard textbook in Philosophy of Science can bluntly state,

As a matter of logic, scientific law can neither be completely established by available evidence, nor conclusively falsified by a finite body of evidence. This does not mean that scientists are not justified on the occasions at which they surrender hypotheses because of countervailing evidence, or accept them because of the outcome of an experiment. What it means is that confirmation and disconfirmation are more complex matters than the mere derivation of positive or negative instances of a hypothesis being tested. (Alex Rosenberg, Philosophy of Science: A Contemporary Introduction. London, Routledge, 2000, p. 114.)

But are the philosophers going off on a tangent, here? No, well informed science educators all accept this point, so that the National Academies of Science publication, Teaching About Evolution and the Nature of Science can say that “the statements of science should never be accepted as ‘final truth.’”

I said Mr. Trzupek’s comments “seem” to show an “astonishing” ignorance, but unfortunately his ignorance isn’t so surprising. The fact is that it is well known to historians and philosophers of science that scientists themselves are often quite ignorant about these things, and even if they aren’t, they don’t spend a lot of time trying to help their students come to the same understanding. The result is that it is perfectly possible for someone like Mr. Trzupek to earn an entire BS in Chemistry, and still believe that “science [is]… all about absolute truths and proofs at the end of the day.” This problem was noted back in 1990 by Virginia Tech philosopher of science Joseph Pitt.

Rarely is a connection made between the different sciences and it certainly is the case that little, if any, effort is made to touch on the history, philosophy or sociology of science. In short, most of our students are exposed to a year of the current (and soon to be obsolete) thinking about biology, or physics or chemistry and we call that science education. That’s a laugh. The situation is not much better in the colleges. While it is true that there are more courses taught there, it is generally the case that in no science or engineering curriculum are students required to take courses in the history, sociology or philosophy of science, nor are they required to consider the relationships among the various sciences. (Pitt, 1990, The myth of science education, Studies in Philosophy and Education, 10, 7-17.)

Given these considerations, here are my conclusions about the Heartland Institute’s recent pontifications on the nature of science.

1. BRAVO to Mike Mann. What he said about the nature of science is spot-on, and scientists need to keep pounding this point home to students and the public. “Proof is for mathematical theorems and alcoholic beverages. It’s not for science.”

2. Mr. Trzupek provides us with an excellent example of what happens when we fail to pound the message in. Here we have a guy who managed to graduate with a degree in chemistry, and still has wildly naive ideas about the nature of science. Thinking that “real science” is a matter of proof, all he has to do to convince himself to reject any branch of science he doesn’t like (climate science, evolutionary science, or whatever) is to point out a few grey areas. I invite Mr. Trzupek to update his thinking about the nature of science so that he can join substantive conversations about climate science. (WARNING: It’s a lot more work.)

3. People like Al Gore, while I appreciate what he and others have done to publicize the problem of climate change, need to knock it off with their pronouncements that “the science is settled.” Warts and all, science has a pretty darn good track record, and everyone knows it. Thanks, but scientists don’t need that kind of help to make our case, because it’s too easy to point out some grey areas in ANY branch of science.

[NOTE: Tamino has also posted about Mr. Trzupek’s nonsense.]