March 10, 2005

Evolutionary theory and falsificationism

In response to a previous posting, commenter Sarah Taylor made several important points. She clearly articulated the view that evolutionary theory is a complex edifice that is built on many observations that fit into a general pattern that is largely chronologically consistent.

She also notes that one distinguishing feature of science is that there are no questions that it shirks from, that there are no beliefs that it is not willing to put to the test. She says that “What makes scientific theories different from other human proposals about the nature of the universe are their courage. They proclaim their vulnerabilities as their strengths, inviting attack.�

I would mostly agree with this. Science does not shy away from probing its weaknesses, although I would not go so far as to claim that the vulnerabilities are seen as strengths. What is true is that the ‘weaknesses’ of theories are not ignored or covered up but are seen as opportunities for further research. Since there is no such thing in science as infallible knowledge, there is no inherent desire to preserve any theory at all costs, and the history of science is full of once dominant theories that are no longer considered credible.

But having said all that, it is not necessarily true that finding just one contradiction with a theory is sufficient to overthrow the theory. In the context of the challenge to Darwinian theory by intelligent design (ID) advocates, Sarah’s statement that “All that any ID devotee has to do is to show ONE fossil 'out of place', to prove the theory doesn't work. Just one horse shoulder blade in a Cambrian deposit somewhere in the world, and we can say goodbye to Darwin� is a little too strong.

Sarah’s view seems to be derived from the model of falsificationism developed by the philosopher of science Karl Popper (see his book Conjectures and Refutations: The Growth of Scientific Knowledge), 1963) who was trying to explain how science progresses. After showing that trying to prove theories to be true was not possible, Popper argued that what scientists should instead do is try to prove theories false by finding a single counter-instance to the theory’s predictions. If that happens, the theory is falsified and has to be rejected and replaced by a better one. Hence the only status of a scientific theory is either ‘false’ or ‘not yet shown to be false.’

But historians of science have shown that this model, although appealing to our sense of scientific bravado, does not describe how science actually works. Scientists are loath to throw away perfectly productive theories on the basis of a few anomalies. If they did so, then no non-trivial theory would survive. For example, the motion of the perigee of the moon’s orbit disagreed with Newton’s theory for nearly sixty years. Similarly the stability of the planetary orbits was an unsolved problem for nearly 200 years.

Good theories are hard to come by and we cannot afford to throw them away at the first signs of a problem. This is why scientists are quite agreeable to treating such seeming counter-instances as research problems to be worked on, rather than as falsifying events. As Barry Barnes says in his T.S. Kuhn and Social Science (1982): “In agreeing upon a paradigm scientists do not accept a finished product: rather they agree to accept a basis for future work, and to treat as illusory or eliminable all its apparent inadequacies and defects.�

Dethroning a useful theory requires an accumulation of evidence and problems, and the simultaneous existence of a viable alternative. It is like a box spring mattress. One broken spring is not sufficient to make the mattress useless, since the other springs can make up for it and retain the mattress’s functionality. It takes several broken springs to make the mattress a candidate for replacement. And you only throw out the old mattress if you have a better one to replace it with, because having no mattress at all is even worse. The more powerful and venerable the theory, the more breakdowns that must occur to make scientists skeptical of its value and open to having another theory replace it.

After a theory is dethroned due to a confluence of many events, later historians might point to a single event as starting the decline or providing the tipping point that convinced scientists to abandon the theory. But this is something that happens long after the fact, and is largely a rewriting of history.

So I do not think that finding one fossil out of place will dethrone Darwin. And ID does not meet the necessary criteria for being a viable alternative anyway, since it appeals to an unavoidable inscrutability as a factor in its explanatory structure, and that is an immediate disqualification for any scientific theory.


Trackback URL for this entry is: Intelligent Design Creationism and the Dover trial: IDC as comparative religion?
Excerpt: Now that there is a new school board elected in Dover, there is an interesting wrinkle to this story. The...
Weblog: Mano Singham's Web Journal
Tracked: November 17, 2005 08:05 AM


Dr. Singham -

We've been discussing just this issue in my SAGES course, and I agree with your notion that one single counter-example cannot disprove a theory. The crucial action is disproving a theory is not the finding of an anomaly or a set of anomalies, but the recognition of these as such and the call for a new paradigm, the decision to buy a new pair of shoes rather than to uncomfortably wedge one's feet into a pair that has ceased to fit.

I've been assigned to write a paper arguing in favor of teaching ID in schools, a viewpoint that offends me as a secularist. What has struck me, though, is the attitude of unassailability I can adopt, given the lack of falsifiability.

This frightens me, in fact. If we are to teach viewpoints in school simply because they are views of dissent, not due to their academic merit, and because they cannot be disproven, why not teach, as Kurt Vonnegut writes in his Slapstick, that at one distant point in human history gravity must have been lighter, to allow the construction of the pyramids, Stonehenge, and the faces of Easter Island?

I recall learning in high school that a statement of fact is a statement that, regardless of whether it is true, could be found to be true or untrue. Any other statement is an opinion, and I would like to think the function of education is to learn facts - ideally correct ones - as opposed to others' opinions. When my AP English teacher forced her - to my mind incorrect - reading of Shakespeare upon the class, I felt that I'd might as well not attend class if we were to learn her view rather than how to argue our own. I feel the same about ID.

Posted by David Mansfield on March 10, 2005 12:01 PM

"Facts" are not generally simple things. Easily observable things and events, like my desk, may be easily acccepted as a fact. But more esoteric facts, like the existence of an electron or the existence of dinosaurs, are actually not things that are directly experienced but inferred. The inferences may be so strong that we treat it as if it were a fact, but it is still an inference.

So a scientific "fact" may just be something that the community agrees is true.

I am not sure that I agree with your recollection that "a statement of fact is a statement that, regardless of whether it is true, could be found to be true or untrue." A false fact seems to be an oxymoron. Are you sure that in your memory a "statement of fact" replaced "scientific statement". That would be more in line with a commonly used marker for what constitutes a measure for separating scientific statements for non-science.

The fact that a statement cannot be easily disproven does not mean it has grounds for inclusion in science classes because, as you point out, this leaves the science curriculum open to all kinds of weird stuff.

Posted by Mano Singham on March 10, 2005 01:22 PM

I was amused by your statement "I've been assigned to write a paper arguing in favor of teaching ID in schools, a viewpoint that offends me as a secularist."

According to Horowitz and Students for Academic Freedom, what you experienced would constitute "academic bullying". But I don't expect him to take up your cause because it goes against the argument that academics bully students to adopt "conservative" positions. Also, I cannot quite see you running to the state legislature or the courts for redress

Would you mind if I use this example in the forum next week on Senate Bill 24? I will leave your name out if you prefer.

Posted by Mano Singham on March 10, 2005 01:27 PM

Dr. Singham -

As regards the definition of a fact, that was a definition given in an English course in distinguishing between facts - more accurately called, as you suggest, scientific statements - and opinions, between verifiable data and judgment calls. I personally would restrict facts to what could be disproven but hasn't been yet, or more broadly, as you suggest, that on which people agree.

(Interesting but digressive note: In an article in Slate, Timothy Noah coined the term "flakt" for facts that nobody acknowledges, in this particular case the success of socialized medicine).

As for the assignment, I doubt it classifies as academic bullying in large part because other students in the class are assigned the opposite viewpoint. The goal is to learn to argue effectively, and stances were assigned randomly from the following list:

1. In favor of teaching ID
2. Against teaching ID
3. Scientists are responsible for the moral consequences of their discoveries
4. Scientists do not bear this responsibility

I merely happened to draw the one argument with which I do not sympathize at all. The benefit has been that researching the arguments in favor of intelligent design has given me a better understanding from which to oppose its presence in schools.

I don't mind if you use my example in next week's forum, but I may have reduced its persuasiveness in providing context.

Posted by Dave Mansfield on March 10, 2005 07:15 PM

I don't know if the word "flakt" will catch on although Noah's idea is interesting.

I think a ""fact" need not be certain or proven true but it must have some positive evidentiary support, not just the absence of negative ones. Otherwise statements like "there exists a race of little green people on a planet orbiting the star Proxima Centauri" would have to be classified as a fact becasue we cannot as yet prove it to be false.

As for your clarification of the "bullying", rather than reducing its persuasiveness, I actually expected that that was the case. I did not doubt that the faculty member in your case was not bullying you. I know that faculty routinely assign students to take positions that they don't believe in. I do it too. And the intent is not malicious nor for the purpose of indoctrination. It is to clarify the issue.

I always tell my students that they should try and improve their *opponent's* arguments, make them as good as possible, because that is the best to understand why you believe what you do. And that is what happened in your case.

But what rabble rousers like Horowitz do is to remove such events from their context. They would take your comment "I've been assigned to write a paper arguing in favor of teaching ID in schools, a viewpoint that offends me as a secularist." and run with it, arguing that you were bullied, and encourage you to complain to higher authorities.

The only catch in your case that prevent them from doing that is that you are the "wrong" kind of victim and harms there view that universities are hotbeds of liberal indoctrination!

Posted by Mano Singham on March 11, 2005 08:28 AM

Randy Barnett has pointed out at the Volokh Conspiracy that an op/ed you wrote for the Cleveland Plain Dealer alleging an urban myth was the product of either purposeful deceit or incompetent research on your part.

How do you respond to the allegations?
FYI, Barnett is also now reviewing another allegation you made in an op/ed denying the truth of another story about a liberal college professor. What should your readers know about what Barnett is going to find out?

Posted by Questions on March 14, 2005 11:28 AM

Well Mr. Questions,

It seems that Dr. Singham based his op-ed on the documentation that SAF provided about the F paper incident. Unfortunately, SAF's original documentation for the event (the Colorado state senate hearing) was not the right documentation for the incident (as the incident was discussed in the hearing).

It seems that this whole misunderstanding was caused by "purposeful deceit or incompetent" publishing practices on the part of SAF.

Furthermore it's best to post comments on the relevent blog entry and not unrelated entries.

Posted by Answers on March 16, 2005 01:40 AM

Perhaps Volokh could have the decency to link to the continuing flow of information, as Mano has shown himself quite willing to do.

Posted by eldan on March 17, 2005 02:10 PM