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True Human Enhancement

On Nicholas Agar’s Humanity’s End: Why We Should Reject Radical Enhancement

Humanities End SOURCE: MIT Press Nicholas Agar's new book explores the ethical implications of the use of present and future technologies to enhance human minds, bodies, and experiences. Agar raises enormous and never-finally-answerable questions about the end—or perhaps, better, ends—of human beings.

If one only glanced at the sexy titles of Nicholas Agar’s last two books, one might think he had undergone a conversion experience: from being for human enhancement in his last book, Liberal Eugenics: In Defense of Human Enhancement, to being against it in his current book, Humanity’s End: Why We Should Reject Radical Enhancement. But one would be wrong. Agar doesn’t choose a side in the battle between those whose tone and language can make them seem like they are either for enhancement, full stop, or against it, full stop.  Instead, he is engaged in an ongoing conversation about enhancement; about, we might say, what true enhancement is.

As this is a review of his latest book, I will merely observe that in the earlier one—Liberal Eugenics—Agar did not argue for the unlimited right of prospective parents to enhance their offspring. He explicitly stated that “liberal eugenicists should be open to the idea that some uses of enhancement technologies are just wrong and should be banned,” and he suggested that those liberal eugenicists needed to distinguish between uses of enhancement technologies that should be banned and ones that should be permitted.[1]

To articulate that distinction, Agar used Francis Fukuyama, Leon Kass, and Bill McKibben as his foils. Though McKibben is a political progressive, Agar labeled him and the other critics as “conservatives.” He construed them as being against enhancement, full stop, and reiterated that, while he was against some uses of enhancement technologies, he was for others.

He also contrasted his view and theirs by pointing out that, whereas they appealed to nature to say what ought not to be permitted, he appealed to nature to say what ought to be. Specifically, he argued that, “If it is morally acceptable to leave in place a given natural arrangement associated with enhanced ability, then it is morally acceptable to engineer an arrangement with the same effects” (pg. 89). That is, he argued that parents should have the right to use technology to produce the sorts of excellent traits or capacities that already occur “naturally” in some rare human beings, but that they should not have the right to seek more than that.

Agar raises enormous and never-finally-answerable questions about the end—or perhaps, better, ends—of human beings.

In the new book, too, Agar seeks to distinguish between enhancements that ought and ought not to be permitted. And again he appeals to nature, but this time he uses the techno-enthusiasts, Ray Kurzweil, Aubrey de Grey, Nick Bostrom, and James Hughes as his foils. Whereas Kurzweil et al. advocate for what Agar calls radical enhancement, Agar advocates for what he calls moderate enhancement.

When I say that here, too, Agar builds his argument on an appeal to nature, I have in mind his foundational premise regarding what he calls “species relativism.”[2] The “relativism” part of that label might at first sound like a rejection of anything resembling an appeal to nature. But Agar holds that there is something good, something worth preserving, about the way members of our species typically or naturally find happiness. As he puts it, “Experiences typical of the ways in which humans live and love are the particular focus of my species-relativism” (pg.15).

So for an enhancement to count as moderate on Agar’s account, it has to be “relative” to our species. As distinct from a radical or “purported” enhancement, a moderate one has to enhance a way of being that is typical of homo sapiens. On his view, the main examples of enhancement found in the philosophical literature count as instances of moderate enhancement.

Take the familiar example of trying to engineer your embryo’s genome so that it will develop the intelligence of an Einstein. Because there’s a big gap in intelligence between Einstein and most ordinary physicists, if such engineering were possible, it would count as an enhancement; it would produce “capacities considerably beyond the norms for humans”(pg. 17). And, because such an enhancement would “not exceed the maximum attainable by any current or past human being”(pg. 17), it would count for Agar as moderate.

So, as he did in his earlier book, Liberal Eugenics, in Humanity’s End he also appeals to nature: to the form of the human species as we currently know it. As he says, “We assign individual organisms to species not on the basis of what happens in human or posthuman laboratories, but according to what occurs in nature”(pg. 22). The “biological species concept” provides the line between moderate and radical enhancement, between enhancements that would allow us to remain human and those that “might send us into biological exile”(pg. 27).

After sketching his primary line of argument in the first couple of chapters, Agar turns to the largest part of the book, made up of his critiques of the four advocates of enhancement I mentioned above.

Agar’s critique of Kurzweil

According to the brilliant cyber innovator, Ray Kurzweil, we have long been on the road to integrating the information-processing power of computers into our fleshly brains; just think, for example, of how the tiny computers in cochlear implants allow people who are born deaf to hear. According to Kurzweil, as the pace of this integrative process increases exponentially, it will be ever more rational to trade in our old-fashioned neurons and synapses for more efficient electronic circuits. This will make “the nonbiological portion of our intelligence…trillions of trillions of times more powerful than unaided human intelligence.” Ultimately, we will transfer our minds from our brains to our machines. Or, as Kurzweil famously puts it, we will “upload ourselves”(pg. 35).

Agar’s first line of critique is simply that, no matter how great the apparent appeal of infinite processing power, such an intelligence would no longer be a human intelligence. Instead of transforming our intelligence into something nonhuman, Agar suggests, we should adopt what he calls “rational biological conservatism”(pg. 57).

His second line of critique is that, if we pursued the radical enhancement of one capacity we value, we might inadvertently undermine other capacities of equal value. That’s of course a point that leaps to the mind of anyone who thinks of human organisms in “ecological” terms, where parts of wholes are interconnected in ways that are hard to discern, and where the results of tinkering are thus hard to predict. In particular, Agar worries that our species-specific form of intelligence might be inextricably entwined with our species-specific forms of desire. He worries that, while radically enhancing our intelligence may not “remove our capacity to protect, promote, and honor” our “strongest moral and political ideals,” it may nonetheless “remove our desire to do so” (pg. 70, ital. added).

While Kurzweil does not think in such “ecological” terms—embodiment is altogether inessential for him—the so-called bioconservatives that Agar critiqued in his previous book do. Agar doesn’t just share with the so-called bioconservatives his sense that radical enhancements could inadvertently produce impoverishments, but also shares with them the idea that there’s something good about the current form of our species that’s worth conserving. Moreover, like them, he thinks that some forms of technological shaping should be resisted—and even says straight out that we should beware of “overly simplistic assertions about the pointlessness of standing in the way of technological advance” (pg. 78).

Agar’s critique of de Grey

Whereas Kurzweil imagines that the way to immortality is uploading our minds to machines, the next subject of Agar’s analysis advocates a very different route. Aubrey de Grey, the computer scientist turned aging researcher, seeks to figure out how to repair or replace the individual parts of those pesky bodies that keep breaking down.

De Grey and his fellow travelers don’t only want to achieve radical life extension, they want to make the ethical case for it. Part of making that case entails leveling the charge of “deathism” against whoever disagrees with them. Essentially, the charge is that, to be against radical life extension is to be for death; but that’s tantamount to advocating for suicide, which no decent person would do. Thus, on de Grey’s view, being against radical life extension is irrational or immoral or both.

And thus it falls to Agar, to try to make the case for, as Leon Kass has put it, “the virtues of finitude.”[3] It falls to Agar to say, why, if we all think that a normal human life span cut short is terrible, it isn’t equally terrible to fail to try to extend a normal human life span. If a long life is good, how could an indefinitely longer one not be better?

Agar’s answer brings us back to his species-relativist premise. He argues that, while it is indeed reasonable to want more of “a recognizably human life,” it is not reasonable to want a form of life without the sorts of experiences that are typical for members of our species. As he says, there are some Galapagos tortoises that live up to 150 years, and they no doubt enjoy experiences that are pleasurable for members of their species, but no human being would trade our “distinctively human varieties of pleasure” for distinctively tortoise varieties of pleasure. Because, however, he grants the respect in which that example is unfair—becoming a tortoise would entail diminished cognition and radical life extension would not—he needs to say more.

He begins by suggesting that de Grey’s “Strategies for Engineered Negligible Senescence” (SENS) might create an obsessive fear of death, which might come to completely dominate the lives of those who adopted such strategies. Agar worries that, because negligibly senescent people would have more years of life to lose if they failed in one of their projects, they would have a strong reason not to take any risks at all (pg. 116). Indeed, at this point he invokes the concern that later in the book he will call its central theme: the concern about alienation, about becoming separated from the kinds of, here, risky experiences that constitute human lives as we know them. According to Agar, de Grey’s ambition to radically extend our lives “is likely to alienate us from the things and people who currently give our lives meaning”(pg. 122).

Agar allows that there may appear to be a way around the obsessive fear of death that SENS could bring about. To get around the risks associated with going out into the real world, he allows, negligibly senescent people could use technologies to have virtual experiences instead. But the problem with that strategy, he says, is that it fails to appreciate the extent to which human beings want “direct” contact with the “real” world. It fails to appreciate that “We think differently about these kinds of indirect contact [with the real world] than we do about ‘being there.’” No one, he suggests, thinks that “seeing a Discovery Channel documentary filmed on Mount Everest substitutes for actually climbing it”(pg. 123).

Moreover, because de Grey’s program of negligible senescence could lead to more and more people living lives of indefinite length, it could lead to overpopulation. Because it would then be irresponsible to reproduce more beings of indefinite life span, the beings who underwent such radical enhancement would come to view cybersex as a perfectly adequate substitute for the old-fashioned varieties, which involve physical interactions between human beings. The problem with the cybersex solution, according to Agar, is that it fails to appreciate that human beings want contact with real human beings as they are, not with virtual substitutes.

Agar is not a prude or a Luddite. He does not appear to object to cybersex, tout court. He is arguing for the value or “truth” of the pleasures that human beings can experience when they come into contact with other human beings as they really are. That is, the lives of negligibly senescing people, like the very long lives of those tortoises, might contain a greater number of pleasurable experiences than the lives of senescing humans, “but those pleasures will not be ours”(pg. 127).

Agar’s critique of Bostrom

Next Agar turns to a different sort of argument on behalf of radical enhancement, this one made by the Oxford philosopher Nick Bostrom. Actually, much of Agar’s critique concerns an argument that Bostrom made with his co-author, philosopher Toby Ord. Bostrom and Ord suggest that claims against enhancement boil down to a preference for the status quo; they boil down to the assertion that, as Agar puts it, “current human intellects and life spans are best because they’re what we have now”(pg. 134).

To make that case, Bostrom and Ord introduce psychological research. One experiment featured two groups of students who filled out a questionnaire, and as compensation for their participation, received gifts of equal monetary value. Members of the first group received a decorated mug and members of the second a large Swiss chocolate bar. Members of both groups were then offered the option of trading their original compensation for the other; someone who received the mug was given the option of trading for chocolate and vice versa. Strikingly, about 90 percent of the participants chose to retain the form of compensation they received first.

Bostrom and Ord’s point is of course that any preference we state for our current level of human intelligence (or anything else) is a symptom of the same status quo bias that affected the recipients of the mugs and chocolate. We don’t want to retain our current level of intelligence because it is inherently more valuable than an enhanced level, we want it because it’s ours.

Bostrom and Ord then propose that, to detect whether status quo bias is at work in someone’s critique of human enhancement, the critic should have to submit to “the reversal test.” To understand how that test works, we have to notice first that most people who oppose the enhancement of human intelligence also oppose its diminishment. Nobody advocates, for example, for diminishing children’s intelligence by putting lead in their milk. According to Bostrom and Ord, the only way it could be rational to oppose efforts to enhance intelligence and oppose efforts to diminish it, would be if the costs or risks were just too high—or “if we could give a good reason for thinking that intelligence is currently at precisely the right level”(pg. 136). If the enhancement critic cannot give a good reason for the rightness of the current level of human intelligence, then, according to Bostrom and Ord, she suffers from status quo bias and her view is unwarranted.

Agar responds to the Bostrom-Ord challenge in a couple of ways. First he points out the difference in our attitudes toward the possible costs or consequences of radical enhancement. Bostrom and Ord say explicitly that “uncertainty of the ultimate consequences of cognitive enhancement, far from being a sufficient ground for opposing them, is actually a strong consideration in their support”(pg. 137-38). After all, Bostrom and Ord ask, what would have happened if our evolutionary forbearers had decided against attempting to enhance their intelligence (with everything from increased caloric intake to writing), on the grounds that they couldn’t foresee the long-term consequences of such enhancements? We would not now enjoy the higher, deeper, richer human experiences that go with having intelligences enhanced well above the norm of our evolutionary forbearers.

That is, Bostrom takes what some transhumanists have called a “proactionary” attitude toward our efforts at radical human enhancement.[4] Yes, he argues, there will no doubt be unintended consequences associated with such efforts, but some of them will be marvelous beyond our current imaginings. In contrast, Agar, adopts what he refers to as a “precautionary” attitude. Here, as well as elsewhere in the book, he invokes the example of global warming to support his case for caution. In addition, borrowing a page from the Bostrom-Ord playbook, Agar then suggests that they labor under the burden of a psychological error: “Focalism” is the human tendency to imagine all of the marvelous (or terrible) consequences of some single change in one’s circumstance—without trying to imagine the terrible (or marvelous) consequences that may attend the same change.

Agar’s second move in response to Bostrom and Ord’s status-quo-error-based argument is to suggest that it achieves less than they think. Even if their argument had succeeded in showing an error in the thinking of radical-enhancement critics, he suggests, it would not have succeeded in showing that radical enhancement is ethically desirable. So Agar takes it upon himself to attempt to say why radical enhancement is not desirable, which gives him another chance to articulate his fundamental argument.

In the first step, he reminds his reader of his species relativist view of value, “according to which some experiences properly valued by members of one species can lack such value for the members of another species”(pg. 139). It would not be “proper” for those Galapagos tortoises to value listening to Bach, even though we may imagine that they take their own kind of pleasure in listening to fish whoosh through the Pacific.

The second step of the argument simply reiterates Agar’s view that the sorts of radical enhancements envisioned by Bostrom et al. would likely “export its recipients from the human species”(pg. 140) to a different, trans- or post-human species. The traits or capacities that radical enhancement gave us might be in some sense superior to ours, but they wouldn’t be ours. He concludes: “Species-relativists should, therefore, be open to the idea that humans might have a rational preference for objectively inferior experiences”(pg. 140). That is, his opposition to radical enhancement does not depend on any bias toward the status quo, but rather on the recognition that radical enhancement might threaten ways of being that we properly value.

Agar’s critique of Hughes

The final subject of Agar’s investigation is James Hughes, who published his transhumanist manifesto Citizen Cyborg in 2004. There Hughes offered a distinction of decisive importance for him: between human beings (any being with a human genome) and persons (any being with self-awareness and desires and plans for the future). Thus, for example, some human beings with the profoundest of cognitive disabilities would not be persons, but gorillas and dolphins would be. Hughes suggested that those who saw things otherwise were “human racists.” That is, he charged them with committing the sin of investing moral significance in the fact of having a human genome, instead of where it properly belongs: in the capacity for self-awareness.

Because Hughes’s contempt for and anger toward those who didn’t share his view was so palpable, he made it easier than he should have for “human racists” to ignore Citizen Cyborg. Agar, however, takes Hughes, not at his worst, but at his best: as an advocate for a “democratic transhumanism,” in which all persons have access to the technologies they want to promote their own flourishing.

Though Hughes does mention that human persons may have a moral obligation to radically enhance and thereby “uplift” nonhuman persons such as chimpanzees and dolphins so that they can participate fully in the transhumanist community, he is also careful to insist that no one should be coerced into becoming posthuman.

That insistence does not, however, comfort Agar. As did Francis Fukyama in Our Posthuman Future, Agar worries that the existence of radically enhanced humans would make it increasingly difficult for anyone to “choose” to remain human. As the radically enhanced gained political power, and as their consequentialist philosophical leanings suggested to them that they had a moral obligation to use radical enhancement techniques to enhance the overall happiness of the society, the pressure to radically enhance would become virtually impossible to resist. Moreover, for those few strong enough to resist, the price would be becoming the member of an under class. Not only would the chasm between the haves and have nots grow still huger, now it would stretch between two different species, each warranting different kinds of respect. In such a scenario, Agar suggests, there is no room for the sort of vital democracy that Hughes envisions.

To make the prospect of radical enhancement darker still, Agar imagines that, because posthumans will have so far surpassed the scientific achievements of mere humans, they will not need the sorts of old-fashioned medical experiments that human scientists perform today. This, he suggests, would open up the possibility that “there will be posthuman purposes that both require the sacrifice of human lives and lead to consequences sufficiently good to justify it”(pg. 169).

Given such prospects, Agar says we have two options. We can enforce the radical enhancement of all, or we can ban it. And, like in his earlier book, he recommends the latter. He does not, however, say how such a ban might be implemented.

And implementation would be no mean feat. In the context of the “treatment-enhancement” debate, Eric Juengst long ago observed that, insofar as many of the very same technologies that could be used to achieve treatment could also be used to achieve enhancement, and insofar as it’s hard to imagine banning a new technology aimed at treatment, it’s hard to imagine how one might actually ban enhancement.[5] It seems equally hard to know how to ban “radical” enhancement, while permitting “moderate” enhancement. That’s not to say it can’t be done, only that it may be easier to say than to do. Moreover, to be fair, though, Agar never promised practical advice.

Alienation: On becoming separated from proper human experiences

In the conclusion of Humanity’s End, Agar names “alienation” as the theme that underlies his critique of radical enhancement. As he puts it, “Radical enhancement alienates us from experiences that give meaning to our lives”(pg. 179).

Agar is acutely aware that talk about the threat of becoming alienated from experiences that give our lives meaning sounds awfully like those “bioconservatives” he used as foils in Liberal Eugenics. And he is acutely aware of the contempt that can be heaped upon anyone who dares to suggest, as he does, that suffering can sometimes be an essential feature of some meaningful and valuable human experiences. Watch out she who dares to ask the “ecological” question, concerning the possible interconnectedness of what is hardest about our lives, including suffering and death, and what is most meaningful! Next she’ll have to answer the enthusiast’s question, “Oh, and do you think that we should reintroduce small pox to give more people more opportunities to find meaning?”

To his credit, Agar isn’t cowed by that question. Indeed, he says that it exhibits “an overly simplistic view of the human significance of disease and suffering”(pg. 181). It fails to duly acknowledge the ecological insight and thus fails to take seriously a reason for exhibiting caution in our efforts to extirpate what’s hardest. Like the so-called “bioconservatives,” Agar explicitly seeks a way to reject the opportunities for meaning making that disease might give us—and to affirm the fact that our species has evolved such that what’s hardest and what’s most valuable or meaningful can sometimes be distressingly interconnected.

Perhaps in his next book, Agar will offer even more specificity regarding which sorts of valuable experiences from which radical enhancement might alienate us. In the final chapter of this book, however, he limits himself to a rather brief survey of three contexts in which he says we should be especially wary of radical enhancement. First, he reiterates that radical enhancement would make it much harder for individuals to have the sorts of “mature interests and attachments” that are made possible by the finite structure of our lives as they have evolved so far. Second, he argues that if parents were to radically enhance their offspring, they could inadvertently create barriers to the sorts of relationships that human parents seek with their children. And finally he suggests that radical enhancement would “alienate us from our sporting heroes” (even more than performance enhancing drugs already do); if our sports heroes become too unlike us, he suggests, we will become alienated from the opportunities for vicarious enjoyment that are currently ours.

It’s time to scrap the label “bioconservative”

I hope I haven’t exaggerated the extent to which Agar’s arguments in this book resemble the arguments of those he called “conservatives” and used as foils in his earlier book. My point hasn’t been that he has switched sides, much less that he is inconsistent. I admire his consistent engagement with thinkers on both sides of the argumentative spectrum.

In showing the extent to which his own arguments resemble those made by the writers he now calls “bioconservatives,” one of my points has been to suggest the respect in which that label is deeply unhelpful. As far as I can tell, Agar is (like me) a political liberal who is impressed both by our extraordinary capacity to use technology to enhance our experiences and thereby ourselves, and by the extraordinary importance of affirming and protecting many of the ways of being that we have evolved to experience. To use language I have floated elsewhere, he seems committed to embracing the “creativity” that has allowed our species to transform itself—and equally committed to exhibiting “gratitude” for our characteristic ways of being human, which we have not created.[6]

Those thinkers Agar calls “bioconservatives”—and Agar himself—bring to our public conversation about human enhancement a willingness to ask questions that too many of us have learned not to ask. Questions like: What is the nature of animals like us? What has to be conserved for members of our species to continue to have the sorts of valuable experiences we’ve evolved to have? What’s the difference between an intervention that can help to make us more whole and one that puts us at increased risk of becoming alienated from ourselves? What’s a true, as opposed to a phony, enhancement?

Indeed, the title of Agar’s new book, Humanity’s End, draws our attention to such questions. The “end” in that title of course refers first to the fact that, in the absence of proper caution, our technological interventions could destroy homo sapiens. But it also seems to refer to the “end” of humanity in Aristotle’s sense of telos: the purpose or nature or proper functioning of human beings. Agar’s inquiries concerning enhancement over the last decade have driven him to raise the enormous, never-finally-answerable questions concerning the end—or perhaps, better, ends—of human beings.

Those of us who have tried to stop asking such questions have had good reason. We are aware of the stupidity and cruelty that have marched under their banner. But as Agar has shown in his last two books, those of us who want to think about how we ought to use new technologies can’t escape them.

Erik Parens, PhD, is a senior research scholar at the Hastings Center.


[1] Nicholas Agar, Liberal Eugenics: In Defense of Human Enhancement (Hoboken: Wiley-Blackwell, 2004), p.15.

[2] For more on “appeals to nature,” see Gregory E. Kaebnick, The Ideal of Nature: Debates about Biotechnology and the Environment (Baltimore: Johns Hopkins University Press, forthcoming 2011).

[3] Leon Kass, “Mortality and Morality: The Virtues of Finitude” in Toward a More Natural Science (Mankato: The Free Press, 1985), p. 299-317.

[4] Max More, “The Proactionary Principle,” Version 1.2, July 29, 2005, available at

[5] Eric Juengst et al., “What Does Enhancement Mean?”In Erik Parens, ed. Enhancing Human Traits: Ethical and Social Implications (Georgetown University Press, 1998), p.29-47.

[6] Erik Parens, “Authenticity and Ambivalence: Toward Understanding the Enhancement Debate,” Hastings Center Report 35 (3) (2005): 34-41.

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