In an article last month in Nature, Ann Reid, executive director of the National Center for Science Education (NCSE), praised the apparent success of efforts to teach Darwin-only curricula in public schools. We’ve addressed some major weaknesses in her account, here, here, and here. Reid’s predecessor, Eugenie Scott, once said, “There are no weaknesses in the theory of evolution.” Reid’s article frames the NCSE’s dogmatic view of evolution as if it is necessary for solving urgent public health crises, such as the current coronavirus pandemic. She’s wrong:
Understanding evolution helped us to make educated guesses about how the [Spanish flu] virus might have changed between 1918 and the 1930s, when influenza viruses were first isolated. This enabled us to design reagents with the best chance of finding the killer virus. Once we had the entire sequence, evolution helped us to understand where the virus came from and how it moved between hosts
As another pandemic sweeps the globe, evolution is again crucial to understanding a pathogen. It helps us to learn how the virus circulates, and to identify its vulnerabilities. It helps us to counter conspiracy theories.
I’m glad scientists are helping to give young people an understanding of evolution as they navigate our complicated world.
Admit No Weaknesses, Cure Fewer Diseases
There is a dangerous irony here. Reid in her article points to medical advances in fighting disease as if they depend on the NCSE’s idiosyncratic and dogmatic version of “understanding evolution.” In fact the progress we all hope for and need depends on rejecting the NCSE’s view on Darwinism. It requires appreciating that there are limits to how much features can evolve.
When combatting disease-causing pathogens, such as bacteria or viruses, we don’t use the idea that Darwinian evolution is of unlimited creativity. Quite the reverse. We design drug cocktails based on the fundamental premise that there are limits to how much viruses and other living systems can evolve. The more drugs we throw at a disease-causing organism, the less likely it is that the organism will be able to evolve the multiple mutations needed to evade the cocktail and survive, thereby becoming resistant. In his book The Edge of Evolution, Michael Behe shows that because there is an “edge” or a “limit” to evolution, we can use drug cocktails to combat antibiotic resistance:
To greatly increase the chances of successful treatment, one strategy is to use a cocktail of drugs, each component of which is able to kill a sizeable chunk of cells. For example, in urging that several drugs should be used simultaneously against malaria, one researcher explained:
“Resistance to antimalarial drugs arises when spontaneously occurring mutants . . . which confer reduced drug susceptibility are selected, and are then transmitted. Simultaneous use of two or more antimalarials … will reduce the chance of selection, because the chance of a resistant mutant surviving is the product of the parasite mutation rates for the individual drugs, multiplied by the number of parasites in an infection that are exposed to the drugs.”
Suppose a cocktail contains two drugs, A and B, and that one in a million parasite cells is resistant to drug A, and one in a million to drug B. Assuming resistance to A is due to a different mutation than resistance to B, then the odds that a single individual cell is resistant to both drugs at the same time are multiplied, a million times a million, which is one in a trillion.
(The Edge of Evolution, p. 56)
How Does the NCSE Respond to Behe?
In a review of his book posted at their website, the NCSE recognized that “Behe’s new thesis is that there are limits to what Darwinian evolution can accomplish.” But they then said he was flat wrong:
Behe’s thesis of evolutionary limits hangs on the assumption that important evolutionary steps require multiple simultaneous mutations without the benefit of cumulative selection. However, there is no evidence to support this claim.
The NCSE review’s assertion is completely false. There are traits that require multiple mutations in order to provide some selectable effect. If this were not so, we would not use drug cocktails that force organisms to acquire multiple mutations — a highly unlikely event — before they can survive the antibiotic dose. To put it another way, if there were no evolutionary limits (due to the fact that some features require many mutations before allowing a survival advantage), then we would have no way to combat many rapidly evolving pathogens.
The NCSE’s philosophy, if put into practice, would prevent us from being able to fight many pathogenic diseases and deal with pandemics. Yet that philosophy is exactly what the NCSE wants students to learn — students, as in our future doctors and medical researchers. Refusing to admit weaknesses in the Darwinian mechanism is not only wrong as science. It also puts health at risk.