Douglas A. Vakoch, SETI Institute and California Institute of Integral Studies

"The Evolution of Extraterrestrials: Life beyond Earth and the Synthetic Theory of Natural Selection"

For many astronomers, the progressive development of life has been seen as a natural occurrence given proper environmental conditions on a planet. And even though such beings would not be identical to humans, they argue, we should expect to find significant parallels. A striking contrast is seen in the writings of scientists from other disciplines, who hold more widely differing views.  One clue to understanding the differences between the anthropologists, paleontologists, and biologists who speculated on extraterrestrials is suggested by an historical analysis, noting who wrote on the subject. Given the relatively small number of commentators on the topic, it seems more than coincidental that four of the major contributors to the evolutionary synthesis in the 1930s and 1940s are among them. Upon closer examination, it is evident that the exobiological arguments of Theodosius Dobzhansky and George Gaylord Simpson, and less directly, of H. J. Muller and Ernst Mayr, are all related to their earlier work in formulating synthetic evolution. By examining the variety of views held more recently by anthropologists, paleontologists, and biologists, we can see that there were significant disagreements among them about evolution as late as the 1960s. By the close of the next decade, however, most had reached a consensus that “higher” life, particularly intelligent life, probably occurs quite infrequently in the universe. Their reasons for these various beliefs suggest a cause for the shift: an increasing acceptance of the evolutionary synthesis.