Today's San Diego Union-Tribune has a story about astronomers Aden and Marjorie Meinel and their hypothesis that a spike in cosmic radiation contributed significantly to the evolution of modern humans. What I admire about the Meinels is that they want to put their hypothesis in empirical harm's way. As the article explains, "They expect their ideas to be questioned and scrutinized. Indeed, they demand it."
I want to do that here by quoting from a relevant passage in The Privileged Planet. Since Jay Richards and I tucked the passage away in an endnote, even readers of the book may have missed it:
Astrophysicists John Scalo and Craig Wheeler of the University of Texas at Austin have argued that high levels of radiation (such as those provided by extraterrestrial sources) accelerate evolution through the generation of beneficial mutations. See J. Scalo, J. C. Wheeler, and P. Williams, “Intermittent Jolts of Galactic UV Radiation: Mutageneic Effects,” Frontiers of Life; 12th Rencontres de Blois, ed. L. M. Celnikier, in press. They base their case on simulations of evolution and supposed laboratory evidence for induced evolution in bacterial cultures. Their primary empirical supporting evidence for this claim is, M. Vulic, R. E. Lenski, and M. Radman, “Mutation, Recombination, and Incipient Speciation of Bacteria in the Laboratory,” Publications of the National Academy of Sciences 96 (1999), 7,348–7,351. While this study has come closer than any other in claiming to produce a new species of bacteria, it has not actually done so. The researchers produced a genetic barrier between two identical lines, which they admit is “much smaller than the barrier between such clearly distinct species as E. coli and Salmonella enterica.” Thus, even with the highly artificial and extreme selective pressures applied by the scientists to rapidly reproducing bacteria in a laboratory setting, there is still no evidence that random genetic mutations yield evolutionary innovations above the species level. There is only evidence for negative mutations, which produce cripples eliminated from a population by natural selection. Add to this the fact that the early Earth experienced much higher radiation levels than it has now, via nearby supernovae, solar flares, and potassium-40 in the oceans, yet life hardly did anything interesting for about two billion years. (p. 386n48)
I should add that in my review paper on "Habitable Zones in the Universe", I employed our uniform experience with the destructive properties of mutation-inducing radiation to support the paper's larger argument concerning the Galactic Habitable Zone. I defended this aspect of the paper to the satisfaction of the reviewers.
The Meinels plan to elaborate on their hypothesis June 20 in a noon public lecture at the University of San Diego, part of the annual meeting of the Pacific Division of the American Association for the Advancement of Science.
To see how Jay Richards and I put our design argument from The Privileged Planet in empirical harm's way, see pages 313-15 of the book.
