“Orphan Black” protagonist Rachel (Tatiana Maslany) attacks a clone of herself in the science-fiction television series. (BBC America)

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.

Charles T. Rubin is author of “Eclipse of Man: Human Extinction and the Meaning of Progress.” He teaches political philosophy at Duquesne University in Pittsburgh.

For its proponents, transhumanism — the idea of using technology to redesign humans beyond our biology — is just common sense. Who doesn’t want to live a healthier, happier and wealthier life? And wouldn’t it be great to live such an “enhanced” life indefinitely? For nearly as long as we have written record, humans have rebelled at the limits of the human condition, but with the development of modern science and technology we have become increasingly able to overcome what once seemed like absolute limits. Advances in fields such as genetics, synthetic biology, neuropsychology, robotics, artificial intelligence and nanotechnology are putting us on the verge of even more radical breakthroughs, allowing us to imagine that we can ultimately rebuild completely the flawed human product that evolution has bequeathed us.

But the transhumanists are not the only ones imagining the impact of these technological possibilities. In popular fictional depictions — such as in Marvel’s superhero television series “Agents of SHIELD” and the much more acclaimed science fiction series “Orphan Black” — “transhumanist” is used more or less as a synonym for “mad scientist.” The notion of humans taking charge of human evolution is strongly associated with those who seem to be the bad guys.

What accounts for this gap between how transhumanists see themselves — as rational proponents of a cause, who seek little more than to speed humanity along a path it already follows — and how they are seen in popular culture — as dangerous conspirators against human welfare? Movies and TV need drama and conflict, and it is possible that transhumanists just make trendy villains. And yet the transhumanists and the show writers are alike operating in the realm of imagination, of possible futures. In this case, I believe the TV writers have the richer and more nuanced imaginations that more closely resemble reality.

With great power ought to come great responsibility. The libertarian strain that is so powerful among transhumanists makes them imagine that such responsibility need be exercised only by individuals making choices about how to modify themselves or their children. What popular culture imagines is that transhumanist promises are being made by flawed human beings to flawed human beings, and that as a result the consequences of their decisions will likely have a broader reach than they anticipate. As a result, the great powers that transhumanism promises are likely to be used not in ways that will solve human problems, but in ways that will perpetuate them yet more terribly.

That is because in a world where we have increasing power to modify our humanity, “enhancements” will still be developed by people who are not yet enhanced. Popular culture asks us to imagine how those individuals, whether in government or private industry, will make their choices in a world where darker human motives like selfishness, greed, and lust for power will play a role in decisions about what needs changing, for whom and at what price. And those seeking enhancement will be subject to their own darker motives: to social pressures, competitive inclinations, market manipulations. Indeed, if human beings are even half as imperfect as transhumanists apparently believe, why should we trust our unenhanced opinions about what would constitute an improvement in our lives?

Of course, any honest transhumanist would admit that the extraordinary powers that we may be on the verge of developing could certainly be used to bad ends. Most would seek to avoid such an outcome. Here, however, another problem arises that pop culture predicts. On “Agents of SHIELD,” for example, the bad end lurking in the background seems to be some extinction-level event for mere humanity, and our displacement by some kind of post-human intelligence. Who would want that?

But in a profound sense, this bad end is the same future that the transhumanists desire. If mere humans are as defective as the transhumanists make out, then surely the rational future, the future to be hoped for, would see us replaced by something far better — something, as roboticist Hans Moravec has happily anticipated, alien to humanity as we know it.

Ultimately, there is no gap. The hopes of transhumanism and the fears exposed by pop culture converge in a way that should give us all pause. It’s more likely to result in dystopia than Utopia.

Explore these other perspectives:

David Vincent Kimel: In defense of transhumanism

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

Ronald Bailey: Technology won’t undermine human dignity. Fear of change will.