In an earlier posting, the question was posed as to whether it was intellectually consistent to reject the findings of an entire modern scientific discipline (like biology) or of a major theoretical structure (like the theory of evolution) while accepting all the other theories of science.

The short answer is no. Why this is so can be seen by examining closely the most minimal of creationist theories, the one that goes under the label of ‘intelligent design’ or ID.

ID supporters take great pains to claim that theirs is a scientific theory that has nothing to do with religion or God, and hence belongs in the school science curriculum. (This particular question whether ID can be considered a part of science or of religion will be revisited in a later posting. This is becoming a longer series than I anticipated…)

ID advocates say that there are five specific biochemical systems and processes (bacterial flagella and cilia, blood clotting, protein transport within a cell, the immune system, and metabolic pathways) whose existence and/or workings cannot be explained by evolutionary theory and that hence one has to postulate that such phenomena are evidence of design and of the existence of a designer.

The substance of their arguments is: “You can claim all the other results for evolutionary theory. What would be the harm in allowing these five small systems to have an alternative explanation?�

Leaving aside the many other arguments that can be raised against this position (including those from biologists that these five systems are hardly intractable problems for evolutionary theory), I want to focus on just one feature of the argument. Is it possible to accept that just these five processes were created by a ‘designer,’ while retaining a belief in all the other theories of science?

No you cannot. If some undetectable agent had intervened to create the cilia (say), then in that single act at a microscopic level, you have violated fundamental laws of physics such as the law of conservation of energy, the law of conservation of momentum, and (possibly) the law of conservation of angular momentum. These laws are the bedrock of science and to abandon them is to abandon some of the most fundamental elements of modern science.

So rejecting a seemingly small element of evolutionary theory triggers a catastrophe in a seemingly far-removed area of science, a kind of chaotic ‘butterfly effect’ for scientific theories.

Scientific theories are so interconnected that some philosophers of science have taken this to the extreme (as philosophers are wont to do) and argued that we can only think of one big scientific theory that encompasses everything. It is this entire system (and not any single part of it) that should be compared with nature.

Pierre Duhem in his The Aim and Structure of Physical Theory (1906) articulated this position when he declared that: “The only experimental check on a physical theory which is not illogical consists in comparing the entire system of the physical theory with the whole group of experimental laws, and in judging whether the latter is represented by the former in a satisfactory manner.� (emphasis in original)

Of course, in practical terms, we don’t do that. Each scientific subfield proceeds along its own path. And we know that there have been revolutions in one area of science that have left other areas seemingly undisturbed. But this interconnectedness is a reality and explains why scientific theories are so resistant to change. Scientists realize that changing one portion requires, at the very least, making some accommodations in theories that are connected to it, and it is this process of adjustments that takes time and effort and prevents trivial events from triggering changes.

This is why it usually requires a major crisis in an existing theory for scientists to even consider replacing it with a new one. The five cases raised by ID advocates do not come close to creating that kind of crisis. They are like flies in the path of a lumbering evolutionary theory elephant, minor irritants that can be ignored or swatted away easily.

Extra note:

For those of you interested in this topic, the Cleveland Museum of Natural History is having an all day symposium on “Teaching Evolution and the Diversity of Life� on Saturday February 12. I am one of the speakers, speaking on the topic “Science and Intelligent Design� in classroom C from 9:45-10:45. Unfortunately the symposium is not free except for the 4:30 pm talk by Dr. Brian Alters.

The Plain Dealer ran a news item about the symposium and related topics in the Metro section yesterday (Thursday, February 10, 2005).

In an earlier posting, I noted that the US population is roughly evenly split on whether or not to accept the basic tenet of evolution on the origin of humans. What is interesting is that the people who reject evolution feel quite free to do so. They seem to feel that there is no price to be paid.

This is because science is taught pretty much as a set of end results and disconnected facts: The universe is over ten billion years old. The Earth revolves around the Sun. Atoms are made from protons, neutrons, and electrons. Trees take in carbon dioxide and release oxygen. Our genetic information is encoded in our DNA.
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First the bad (and somewhat old) news. In a 2001 survey, the National Science Foundation found that only 53 percent of Americans agreed with the statement “human beings, as we know them, developed from earlier species of animals.�

It is hard to believe that there could be any good news behind this mind-boggling statistic that implies that up to 47 percent of Americans are unwilling to accept a fundamental tenet of evolution and believe that human beings appeared by a special act of creation about 10,000 years ago.

But there is a nugget of good news to be found, since this is the first time that even a simple majority of Americans had accepted that statement.

But even that small glimmer of hope is buried under more bad news. Even though a majority has come around to the accepted scientific view of the origin of humans, the US still lags far behind other countries. In a New York Times article on February 1, 2005, Dr. Joe Miller, director of the Center for Biomedical Communications at Northwestern University is quoted as saying that in other industrialized countries, 80 percent or more typically accept evolution, while most of the others say they are not sure and very few people reject the idea outright.

He goes on to say that in socially conservative, predominantly Catholic countries like Poland, perhaps 75 percent of people surveyed accept evolution, while in Japan it is close to a whopping 96 percent.

So what is different about the US? There are some obvious reasons that can be postulated. One is that the US is in the grip of Biblical literalists who indoctrinate young children with young-Earth ideas and frighten them with the flames of hell if they should deviate from that dogma.

Another is that evolution is either not being taught at all, or is being taught badly so as to be unconvincing, or its teaching is being deliberately undermined (such as using disclaimer stickers in biology textbooks that evolution is “only a theory”, teaching of ‘intelligent design’ as an alternative) by fraudulent claims that it is not a scientifically acceptable theory. The response to these kinds of explanations is to argue for more and better teaching of evolution in schools.

While I am all in favor of better teaching of anything, I am not convinced that inadequate teaching of evolution is the main problem. It may lie in the way the nature of science is taught, and correcting this might require us to pay more close attention to the image we convey of how science itself works and evolves. This may require us to focus, not on more teaching of evolution or any other specific topic, but more generally on the history and philosophy of science.

More about this in a later posting…

Dan had a comment on the “science and proof II” posting that I think is of general interest that requires a fresh posting. He asks:

“Okay, do you have a quick explanation for why falsification is not the distinction between science and religion?

On a day to day level, it works for me. If someone says there exist leprechauns, but they are invisible, and leave no trace in our world, I know that the statement can not be proven wrong so it is not worth arguing against. But if someone says that species evolve from other species, it is conceivable that it could be proven wrong, so it is worth taking seriously. And if enough people try to disprove it and fail, that is good evidence that it might have explanatory power.”

Dan’s point is a good one. At a simple level, falsificationism sounds plausible. The theory that “All swans are white” can be seemingly falsified by the appearance of aa single black swan. Falsification’s appeal stems from the fact that we seem to be able to make a clean distinction between an observation and a theory.

But that distinction becomes blurred when you start looking at the kinds of things that scientists research, because then observations are no longer simple sensory perceptions. The statement “electrons exist” is not a simple observational one but requires us to use a vast array of theories from a range of disciplines in order to interpret the readings of the measuring insruments. So if the “observation” disagrees with the theory being examined, it is not clear where to place the blame. Is it on the theory being tested, or on one of the theories underlying the observations?

So in reality one is always comparing one set of theories with another set of theories and there is no rule that *forces* you to make a particular choice, although good taste and judgment and standard practices may lead the scientific community to a consensus decision.

The other problem with using falsification is that no theory has ever explained everything in its domain. There are always unsolved problems and contradictory results. Trying to reconcile these discrepancies serve as the basis for much research. If we applied the falsification rule strictly, then every theory we have would be falsified.

These are the kinds of things that caused falsificationism to stumble and fall.

Incidentally, even the swan example is not as simple as it looks. Defenders of the white swan theory can retain their belief by arguing that what constitutes a swan is not precisely defined and that the black creature was not really a swan, and other arguments like that. We may dismiss those arguments as silly and self-serving but they are not logically ruled out.

Warning! Shameless plug coming up!

All these issues are discussed in my book “Quest for Truth: Scientific Progress and Religious Beliefs”, published by Phi Delta Kappan Foundation in 2000.

In his comment on my earlier posting on “Science and Proof”, Kurtiss Hare raises an interesting point about the value of religion and what kind of validity criteria I was referring to, so I thought I would elaborate.

When it comes to the *value* of belief structures to an individual, then there are really no external criteria that can be imposed. For example, for someone who has experienced a personal tragedy, a belief in God and a divine purpose for life may be of far more value than all the science in the world.

The point I was trying to muddle through to about science is that it is not being “proven true” that gives scientific theories their credibility, but the fact that they seem to work well, are reliable, and can be used to make predictions.

The probability argument that Kurtiss raises is interesting but has two directions in which it can be taken. The first (which I think is the one he makes) is that the fact that very few planes crash means that the probability of that particular application of the scientific theories (i.e., arriving safely) is high.

But does that translate into a high probability of the underlying scientific theories being true? No, because if you you want to assign a “truth probability” to a scientific theory then you have to compare (for any given theory) the number of predictions that are confirmed to the total number of predictions that are conceivable. Since for any non-trivial theory the number of possible predictions is infinite, the truth probability for *any* theory (however “good”) turns out to be zero!

This seems paradoxical but philosophers of science have not been able to get around it.

On a plane earlier this week, I was seated next to a very nice woman and we struck up a conversation that quickly turned to religion. She was a Biblical literalist who belonged to an evangelical Christian church. In the course of comparing the scientific and religious approaches to describing the world, she made the claim that the theories of evolution and the big bang had not been “proven” and that thus they were articles of faith, just like any religious dogma.

This is a familiar argument to anyone (like me) who has been involved in the whole brou-ha-ha about whether “intelligent design” should be taught alongside Darwinian natural selection in science classes, and it reveals a common misperception about the nature of science.

This view is not held just by religious people, it is widespread. In the first class in my course on the history and philosophy of science, I ask students how they would distinguish science from non-science and invariably they begin by saying that science consists of things that have been proven true.

But nothing, even the most robust of theories, is “proven to be true” in science. But does that mean they are pure articles of faith, on a par with religious beliefs? Surely not. Newton’s laws and the laws of hydrodynamics have not been proven true either, but the woman and I both boarded the airplane confident that the those laws would hold and that we had a very high chance of arriving safely at our destination. Are there any religious beliefs to which we would trust our lives as confidently?

Clearly, the fact that the laws of science are not proven true does not diminish their worth and validity. Thus their credibility must be based on something other than simple proof. But most teaching of science, at any level, pays little attention to this important feature of scientific knowledge. And so the public policy discussions on issues like intelligent design rarely get beyond a fairly simplistic level.

Too bad.