Graffiti partially seen above floodwaters in Paraguay last year. (Jorge Adorno/Reuters)

Each week, In Theory takes on a big idea in the news and explores it from a range of perspectives. This week, we’re talking about transhumanism. Need a primer? Catch up here.

Ronald Bailey is the science correspondent for Reason magazine and author of “Liberation Biology” and “The End of Doom.”

“What ideas, if embraced, would pose the greatest threat to the welfare of humanity?” When the editors of Foreign Policy magazine posed this question to a group of prominent policy intellectuals in 2004, neoconservative thinker Francis Fukuyama chose transhumanism as the world’s most dangerous idea.

In his response to the question, Fukuyama described transhumanism as “a strange liberation movement” that wants “nothing less than to liberate the human race from its biological constraints.” He isn’t alone in his alarm. This year, from the left of the political spectrum, Marcy Darnovsky from the Center for Genetics and Society warned that with the development of new effective gene-editing techniques “we could see the emergence of genetic haves and have-nots, with new forms of inequality and discrimination.”

The prospect of technologically enhanced humans flourishing makes some people uncomfortable. The “bioconservative” alliance of moralizing neoconservatives and egalitarian left-wingers fears that the new bio-, nano-, and info-technologies threaten human dignity and human equality, but these egalitarian worries are overblown — and, in fact, they go against the liberal society that transhumanism’s opponents revere.

Transhumanists advocate the advancement and application of modern biotechnology, nanotechnology and information technology to empower human beings to evolve and flourish beyond their current physical, cognitive, psychological and even moral limitations. One of the chief transhumanist objectives is to radically lengthen healthy human life expectancy, enabling people to thrive for hundreds, if not, thousands of years. On the horizon are technologies that can safely and comprehensively edit human genomes to cure illnesses and repair immune responses.

Last year, researchers at the Albert Einstein College of Medicine launched an anti-aging study using the drug metformin. Dutch researchers have recently shown that dosing fearful people with the anti-hypertension drug propranolol significantly reduces the emotional effects of bad memories. As rejuvenation treatments lengthen life spans, humans might achieve what theoretical bio-gerontologist Aubrey de Grey calls “longevity escape velocity,” in which advances in anti-aging technologies proceed faster than the people taking them age. Thus, life expectancy indefinitely lengthens. Others, such as futurist Ray Kurzweil, foresee digital technologies melding with human bodies. Think of something like cochlear implants that boost your intellectual processing power by wirelessly connecting your brain to banks of supercomputers.

The enhancements that are likely to be available in the relatively near term will be pharmacological — pills and shots to increase strength, lighten moods and improve memory. Consequently, such interventions could be distributed to nearly everyone who wanted them. Later in this century, when safe genetic engineering becomes possible, it will likely be deployed gradually and will enable parents to give their children beneficial genes for improved health and intelligence that other children already get naturally.

Can everyone afford such treatments? Consider that if the U.S. economy grows at a modest 2.5 percent annually until the end of the century, GDP per capita for 450 million Americans would rise to nearly $300,000, up from $55,000 today. In addition, compounding synergies between bio-, nano- and info-technologies will trace the steeply declining cost curves of today’s digital technologies — for example, Kurzweil predicts that the computing power equivalent to a human brain will cost about $1,000 by the beginning of the next decade. Thus, cheap and safe genetic engineering in the long run is more likely to ameliorate than to exacerbate human inequality.

The Enlightenment project that spawned modern liberal democracies sought to keep certain questions about the transcendent out of the public sphere. To keep the social peace and allow varying visions of the human to flourish alongside one another, questions about the ultimate meaning and destiny of humanity were deemed to be private concerns. In our own time, technologies dealing with birth, death and the meaning of life need protection from meddling — even democratic meddling — by those who want to control them as a way to force their visions of right and wrong on the rest of us. Hostility to the prospect of technological enhancement must not be used as an excuse to breach the Enlightenment understanding of what belongs in the private sphere and what belongs in the public.

One crowning achievement of Enlightenment humanism is the principle of tolerance, of putting up with people who look different, talk differently, worship differently and live differently than we do. In the future, our descendants may not all be unenhanced Homo sapiens, but they will still be moral beings who can be held accountable for their actions. There is no a priori reason to think that the same liberal political and moral principles that apply to diverse human beings today would not apply to relations among future humans and transhumans.

The highest expression of human nature and dignity is to strive to overcome the limitations imposed on us by our genes, our evolution and our environment. Future generations will look back at the beginning of the 21st century and be astonished that some well-meaning and intelligent people actually wanted to stop bio-nano-infotech research and deployment just to protect their cramped and limited vision of human nature. If transhumanism is allowed to progress, I predict that our descendants will look back and thank us for making their world of longer, healthier and abler lives possible.

Explore these other perspectives:

Charles T. Rubin: Transhumanists are searching for a dystopian future

David Vincent Kimel: In defense of transhumanism

James J. Hughes: Soon we’ll use science to make people more moral