Beyond Human: How Cutting-Edge Science Is Extending Our Lives, by Eve Herold, St. Martin's Press, 291 pages, $26.99

"Transhumanism is becoming more respectable, and transhumanism, with a small t, is rapidly emerging through conventional mainstream avenues," Eve Herold reports in her astute new book, Beyond Human. While big-T Transhumanism is the activist movement that advocates the use of technology to expand human capacities, small-t transhumanism is the belief or theory that the human race will evolve beyond its current physical and mental limitations, especially by means of deliberate technological interventions. As the director of public policy research and education at the Genetics Policy Institute, Herold knows these scientific, medical, and bioethical territories well.

Movements attract countermovements, and Herold covers the opponents of transhuman transformation too. These bioconservatives range from moralizing neocons to egalitarian liberals who fear the new technologies somehow threaten human dignity and human equality. "I began this book committed to exploring all the arguments, both for and against human enhancement," she writes. "In the process I have found time and again that the bioconservative arguments are less than persuasive." (Herold cites some of my own critiques of bioconservatism in her book.)

Herold opens with a tale of Victor Saurez, a man living a couple of centuries from now who at age 250 looks and feels like a 30-year-old. Back in dark ages of the 21st century, Victor was ideologically set against any newfangled technologies that would artificially extend his life. But after experiencing early onset heart failure, he agreed have a permanent artificial heart implanted because he wanted to know his grandchildren. Next, in order not to be a burden to his daughter, he decided to have vision chips installed in his eyes to correct blindness from macular degeneration. Eventually he agreed to smart guided nanoparticle treatments that reversed the aging process by correcting the relentlessly accumulating DNA errors that cause most physical and mental deterioration.

Science fiction? For now. "Those of us living today stand a good chance of someday being the beneficiaries of such advances," Herold argues

Consider artificial hearts. In 2012 Stacie Sumandig, a 40-year-old mother of four, was told that she would be dead within days due to heart failure caused by a viral infection. Since no donor heart was available, so she opted to have the Syncardia Total Artificial Heart (TAH) installed instead. The TAH completely replaces the natural heart and is powered by batteries carried in backpack. It enabled Sumandig to live, work, and take care of her kids for 196 days before a donor heart became available. As of this month, 1,625 TAHs have been implanted; one person lived with one for 4 years before receiving a donor heart. In 2015, an ongoing clinical trial began in which 19 patients received permanent TAHs.

Herold goes on to describe pioneering research on artificial kidneys, livers, lungs, and pancreases. "Artificial organs will soon be designed that are more durable and perhaps more powerful than natural ones, leading them to become not only curative but enhancing," she argues. In the future, people will be loaded up with technologies working to keep them healthy and alive. (One troubling issue this raises: What do we do when someone using such biomedical technologies chooses to die? Who would be actually be in charge of deactivating those technologies? Would the law treat deactivation by a third party as tantamount to murder? In such cases, something akin to today's legalized physician-assisted dying may have to be sanctioned.)

Artificial organs have considerable competition too. Herold, unfortunately, does not report on the remarkable prospects for growing transplantable human organs inside pigs and sheep. Nor does she focus much attention on therapies using stem cells that could replace and repair damaged tissues and organs. But such research supports her view that biotechnologies, information technologies, and nanotechnologies are converging to yield a plethora of curative and enhancing treatments.

The killer app of human enhancement is agelessness—halting and reversing the physical and mental debilities that befall us as we grow old. Herold focuses a great deal of attention on the development of nanobots that would patrol the body to repair and remove the damage caused as cellular machinery malfunctions over time. She believes that nanomedicine will first achieve success in the treatment of cancers and then move on to curing other diseases. "Then, if all goes well, we will enter the paradigm of maintaining health and youth for a very long time, possibly hundreds of years," she claims. Perhaps because research is moving so fast, Herold does not discuss how CRISPR genome-editing will enable future gerontologists to reprogram old cells into youthful ones.

Herold thinks these technological revolutions will be a good thing, but that doesn't mean she's a Pollyanna. Throughout the book, she worries about how becoming ever more dependent on our technologies will affect us. She foresees a world populated by robots at our beck and call for nearly any task. Social robots will monitor our health, clean our houses, entertain us, and satisfy our sexual desires. Isolated users of perfectly subservient robots could, Herold cautions, "lose important social skills such as unselfishness and the respect for the rights of others." She further asks, "Will we still need each other when robots become our nannies, friends, servants, and lovers?"

There is also the question of how centralized institutions, as opposed to empowered individuals, might use the new tech. Behind a lot of the coming enhancements you'll find the U.S. military, which funds research to protect its warriors and make them more effective at fighting. As Herold reports, the Defense Advance Research Projects Agency (DARPA) is funding research on a drug that would keep people awake and alert for a week. DARPA is also behind work on brain implants designed to alter emotions. While that technology could help people struggling with psychological problems, it might also be used to eliminate fear or guilt in soldiers. Manipulating soldiers' emotions so they will more heedlessly follow orders is ethically problematic, to say the least.

Similar issues haunt Herold's discussion of the technologies, such as neuro-enhancing drugs and implants, that may help us build better brains. Throughout history, the ultimate realm of privacy has been our unspoken thoughts. The proliferation of brain sensors and implants might open up our thoughts to inspection by our physicians, friends, and family—and also government officials and corporate marketers.

Yet Herold effectively rebuts bioconservative arguments against the pursuit and adoption of human enhancement. One oft-heard concern is that longevity research will result in a nursing-home world where people live longer but increasingly debilitated lives. That's nonsense: The point of anti-aging research is not to let people be old longer, but to let them be young longer. Another argument holds that transhuman technologies will simply let the rich get richer. Herold notes that while the rich almost always get access to new technologies first, prices then come down quickly, making them available to nearly everyone eventually. She is confident that the same dynamic will apply to these therapies.

Bioconservatives often assert that enhancement technologies must be banned because that they and theirs will experience irresistible social pressure to use them just to stay competitive. Herold tartly replies, "It's every individual's responsibility to make choices that he feels are good for him. It's not society's responsibility to limit the freedom of other people so that one can feel good about his choices." Bioconservaties, she notes, "fail to make a case for why those who oppose enhancement should be able to exercise free choice while those who desire it should not."

What about concerns about authenticity and dehumanization? Here Herold quotes me: "Nothing could be natural to human beings than striving to liberate ourselves from our biological constraints." Herold observes that no one has ever really come up with a good definition of human nature. As we embark on the inevitable transhumanist journey, she correctly concludes that "we may only ever see who we are today in the rearview mirror, from a state far more advanced than where we find ourselves now." Let's go find out who we really are.