WHAT COMES AFTER HOMO SAPIENS?

A scientist explores the possibility that a new human species could arise within the next two centuries.

It seems like fantastical sci-fi fodder: the emergence of a new, intelligent species that shares the Earth with us—maybe as partners and maybe as rivals. But debut author Simborg, a physician, contends that it’s not only possible, but also likely that a new species—he dubs it “Homo nouveau”—will eventually appear. This sort of species coexistence is historically the evolutionary norm, he says; for a stretch of at least 10,000 years, he points out, Homo sapiens lived side by side with Homo neanderthalensis and Homo denisova. And although we’re still subject to Darwinian evolution—we’ve undergone seismic transformations in the last 40,000 years—the new humans, he says, won’t be the result of it or of the natural, accidental branching of a new species from the existing one. Instead, he argues, Homo nouveau will be birthed by genetic engineering—more specifically, germline genetic therapy, which, he says, can allow new traits to be passed on to offspring. For example, he writes, this type of genetic editing could be used on a portion of the population to prevent a disease, and then that group could interbreed for generations. (For the sake of hypothesis, the original alteration doesn’t make breeding problematic by, for instance, increasing the possibility of miscarriage.) Such a combination of technologically sophisticated action and ungovernable accident, he asserts, could eventually give rise to Homo nouveau. Given the extraordinary leaps in genomic science and the likelihood that such germline editing will become both more effective and popular, he avers, it seems plausible that a new species will materialize. Simborg travels a wide expanse of scientific and philosophical terrain with astonishing brevity. In order for his book to be accessible to the layperson, he needed to quickly explain concepts surrounding species and natural selection, and he accomplishes this with clarity and the breeziest style that such technical subject matter permits. The author also ably furnishes a minihistory of evolution, appraising the theoretical interpretations of Charles Darwin, Jean-Baptiste Lamarck, and Gregor Mendel. Perhaps more impressive, though, is that Simborg’s thesis compels him to take readers on a tour of multiple disciplines, including neuroscience, artificial intelligence, and anthropology. For example, over the course of this work, he thoughtfully discusses and critiques futurist Ray Kurzweil’s predictions regarding the singularity, the moral issues raised by genetic editing, and the difficulty of defining life itself. Even stripped of its provocative hypothesis regarding Homo nouveau, this study supplies a magisterially synoptic introduction to evolutionary science and its sister fields. Furthermore, Simborg’s zeal for scientific explanation doesn’t keep him from being sensitive to abiding mysteries; he concedes a whole host of unanswered questions, including those regarding the genesis of life on Earth: “This book is certainly not finished, and the answers are certainly not resolved. Not a week goes by that I don’t read something newly published that is relevant to the answers.”

A captivating prediction about the future of mankind.