Evolution and biological complexity are the products of random mutation and natural selection at the level of genes.
What they say. . .
Darwin ’s theory of evolution by natural selection hinged on the idea that advantageous traits in an organism would enable it to better adapt to its environment and thus survive to reproduce. But he could never figure out how these traits were passed on from parent to offspring. It wasn’t until twenty years after his death, when scientists unearthed Gregor Mendel’s discovery of genetics, that an answer was found. Through the marriage of Darwin’s and Mendel’s ideas, the Neo-Darwinists created what’s called the “modern evolutionary synthesis,” which says that natural selection is the mechanism of evolution and genes are the units on which it operates. What accounts for biodiversity and novelty, they argue, are random mutations in genetic material, which give the organism an evolutionary advantage and which are then passed on to the next generation.
Thus, evolution really boils down to this competition of genes for survival, or their “selfishness,” as Richard Dawkins famously put it. During the 1970s, entomologist E.O. Wilson created the field of sociobiology based on this idea, arguing that human behavior is influenced by genes and their impetus to reproduce. Over the last decade, Neo-Darwinists have also used the gene-centric perspective to examine everything from consciousness (Daniel Dennett) to the human race’s historical tendency to believe in a God (Dawkins).
What it means. . .
The significance of Neo-Darwinism can’t be overstated. For nearly a century it has exerted a foundational influence over all other evolutionary theories, and it remains the dominant view held by both the scientific establishment and the cultural mainstream today. In recent decades, however, it has come under attack from two different fronts. On the one hand, scientists have argued that Neo-Darwinism’s narrow focus on random mutation and natural selection doesn’t nearly begin to explain the processes we observe in the natural world. On the other hand, many religious scholars, such as Huston Smith, criticize the Neo-Darwinists for the antireligious conclusions that are common in the field and for their insistence that all causal mechanisms of evolution must be material, which they point out is a philosophical conclusion, not a scientific one. It’s a criticism that is gaining currency in the culture at large. Literary critic Leon Wieseltier, for instance, wrote recently in the New York Times, “Scientism, the view that science can explain all human conditions and expressions, mental as well as physical . . . [is] one of the dominant superstitions of our day.”
“We are survival mechanisms—robot machines blindly programmed to preserve the selfish molecules known as genes.”
DID YOU KNOW?
Stephen Jay Gould (1941–2002), one of the most brilliant and passionate scientists of the twentieth century, was renowned for his insistence that life is an accident and evolution is in no way a directional process. It was a belief shared by fewer and fewer toward the end of his life—even famous Neo-Darwinists such as Dennett and Wilson concede that evolution appears to have some direction toward greater complexity. Gould nevertheless insisted that we have to “abandon progress or complexification as a central principle [of evolution] and come to entertain the strong possibility that H. sapiens is but a tiny, late-arising twig on life’s enormously arborescent bush—a small bud that would almost surely not appear a second time if we could replant the bush from seed and let it grow again.”