Appendix A: Debates Over the Definition of “Enhancement”

“I know it when I see it.”

– Supreme Court Justice Potter Stewart, defining obscenity in Jacobellis v. Ohio (1964) (1)

Because Our Grandchildren Redesigned is about the enhancement of human traits, it would be nice to commence by laying out a clear definition of what “enhancement” means. Unfortunately, this turns out to be impossible. Enhancement is one of those slippery customers, like “obscenity,” “justice,” or “freedom,” that stubbornly resists being pinned down, because it conveys an extremely wide range of meanings to different people under varying circumstances.

Let us begin with Exhibit A – a remarkable article published in December 2008 in the scientific journal Nature, under the title “Towards responsible use of cognitive-enhancing drugs by the healthy.” (2)  The authors (a distinguished group of British and American scholars) note that the off-label use of pharmaceuticals like Ritalin or Provigil to boost mental acuity in healthy persons is increasing dramatically, not only on college campuses but in the business world and the military as well. (Indeed, an informal survey conducted by Nature among its readers earlier in 2008 yielded the astonishing revelation that fully twenty percent of the 1400 respondents used such drugs – many of them on a daily or weekly basis – to augment their own cognitive performance.) (3) Current laws in both the UK and US reflect a long-standing attitude of moral disapproval regarding these kinds of chemical enhancements; accordingly, selling such drugs to another person for off-label use carries the possibility of stiff fines and even prison sentences.

This is an unreasonable state of affairs, according to the article’s authors. Boosting our cognitive capacities is a perfectly benign and logical thing to do, they argue, and we need to stop criminalizing it and pushing it underground.

“Human ingenuity has given us means of enhancing our brains through inventions such as written language, printing, and the Internet. … And we are all aware of the abilities to enhance our brains with adequate exercise, nutrition, and sleep. The drugs just reviewed, along with newer technologies such as brain stimulation and prosthetic brain chips, should be viewed in the same general category as education, good health habits, and information technology – ways that our uniquely innovative species tries to improve itself.” (4)

The conceptual move being deployed here is a rather straightforward one. Because these authors wish to open the door for cognitive enhancements as part of the legitimate everyday functioning of our society, they simply collapse the distinction between such enhancements and other forms of beneficial human activity. Even when I’m sleeping, according to them, I am in one sense “enhancing” my ability to function better the next day. By this use of the term, eating a peanut butter sandwich is not qualitatively different from having a prosthetic hippocampus implanted in my brain: both “interventions” result in a net augmentation of my ability to think, as compared with what would have been my ability if I had not undertaken them. (I can never think clearly on an empty stomach.)

This is unhelpful argumentation at best – falling under Hegel’s famous category of “the night in which all cows are black.” Whether or not we agree about the desirability of allowing freer access to mind-boosting drugs (I happen to be among those who somewhat ambivalently support this position), we need to start with a frank assessment of the qualitative differences that divide some forms of biotechnological intervention from others. A Boeing 747 is qualitatively different from a pogo stick, even though both devices render me temporarily airborne.

* * *

I will begin by defining the term “enhancement” rather broadly, as follows: an intervention designed to modify a person’s traits, adding qualities or capabilities that would not otherwise have been expected to characterize that person. Such an intervention can vary in at least three dimensions:

a. Differences of degree: tweaking vs. transmogrifying

The word “enhancement” can cover a disconcertingly wide range of modifications. Its purview ranges from minute adjustments in a person’s biochemistry (“I enhanced my immune system by sucking on a zinc lozenge”) to wholesale redesign (“My latest enhancement package includes infrared vision, Google accessible by thought, perfect photographic recall, and an ability to learn very quickly how to play the piano”).

b. Differences of mode: boosting vs. adding vs. radical remolding

Enhancement can take three qualitatively different forms: modifying an existing trait (“My memory has been far better since the doctors re-engineered my hippocampus”), as opposed to adding a new capability that other humans possess but that I have never possessed before (“I used to be completely tone deaf, but my new bioelectronic implant has endowed me with perfect pitch”). Finally, enhancement can also mean adding a radically new trait that no human has ever possessed before (“This somatic gene retrofit for skin chlorophyll allows me to absorb solar energy directly by photosynthesis”).

c. Differences of relative effect: competitive advantage vs. intrinsic benefit

Some enhancements are specifically designed to boost an individual’s performance in competitive situations (“Steroids have allowed me to win more blue ribbons in weight-lifting than I had ever dreamed”). Others confer a form of intrinsic benefit that is not primarily measured in relation to other people, but rather in relation to one’s own prior condition (“Since I started taking Prozac, I have been more peaceful and joyous than I ever thought possible”). Many enhancements, of course, will be found to confer both these kinds of goods simultaneously (“Since I started using Ritalin to boost my concentration, I have not only outperformed many of my classmates in law school, but am now able to enjoy Mozart in a wholly new way”).

Unfortunately, these three dimensions of variation in the meaning of the word “enhancement” far from exhaust its elusiveness as a concept. Here are three other key areas of irreducible tension or ambiguity surrounding this term.

1. Enhancement vs. normal or species-typical functioning

At one level, this seems like a perfectly reasonable distinction from which to start. Humans do not have wings and cannot fly. Therefore, if we add wings to some individuals through an ingenious application of bioengineering, enabling them to flutter about over short distances, we are broadening the normal human range of function for those persons. In other words, we are taking a circumscribed area of capabilities – how humans move from place to place – and augmenting it by adding a new form of locomotion that is not typical of the species. This constitutes, unambiguously, an enhancement.

So far so good. Some bioethicists rely heavily on this distinction as they seek to draw a line between “bad” enhancements and “good” forms of intervention that seek merely to restore normal or species-typical human function to someone who has lost it. (5)   Unfortunately, the example just given only works because humans have never possessed wings. In most other domains, the act of enhancement is based on augmenting or refining existing human traits and capabilities – and it is here that we run into trouble.

It turns out that the concepts of the “normal” and “species-typical” are fraught with ambiguities. What is normal in one culture, or in one historical era, becomes atypical or downright weird in another. A few years ago, for example, I visited the Doge’s palace off Piazza San Marco in Venice. I kept banging my head on the stone doorways, many of which were cut to a height of about five-foot nine. I am five-eleven, which is close to average for an American male in 2013. In sixteenth-century Venice I would have been regarded as a Titan among men. What is normal height? The answer clearly depends on when you take your measurements to build your data set, and on whom you include in the pool of the measured.

The same goes for mental capabilities. What is normal IQ? In the 1980s the political scientist James Flynn conducted a study of IQ test results from fourteen nations, covering the period 1918-1978 for the United States and a variety of other 20th-century time-spans for the other countries. (6)  The results were striking: people in all the industrialized democracies seemed to be getting steadily smarter (at least according to whatever it is that an IQ test measures). Someone who took the test in 1918 and got a score of 100 (which is by definition the average for any given year) would only have scored 75 in the 1978 test. Similar results manifested themselves overseas as well: the raw scores went up an average of three points per decade in the nations studied. Most importantly, these results applied not just to measurements of factual knowledge such as vocabulary or scientific principles, but equally to measurements of abstract reasoning and spatial skills. Flynn tentatively attributed the rise in performance to the significant improvements in education, literacy, and nutrition that characterized the twentieth century.

The relevance for our present purposes is clear. What counted as statistically normal in 1918 became, by 1978, a score five points away from an official status of “mild mental retardation”! (7) Were most people really that much dumber back then? I doubt it – and so does Flynn. (8) But this example only serves to underscore the extremely problematic nature of both IQ tests in general and the concept of “normal” function in particular.

No one would wish to deny, of course, that a normal human body temperature is 98.6 degrees Fahrenheit. I was born with two feet, not zero or three, and even though some individuals exist who do not match this bipedal characteristic, it nonetheless remains quite useful to describe it as species-typical. Shoe factories are banking on it. Nevertheless, even in medicine, the word “normal” can convey a bewildering variety of meanings, some of them mutually contradictory. According to the scholars Phillip Davis and John Bradley,

“‘normal’ can refer to ‘a defined standard,’ such as normal blood pressure; a ‘naturally occurring state,’ such as normal immunity; ‘free from disease,’ as in a normal pap smear; ‘balanced’ as in a normal diet; ‘acceptable’ as in normal behavior; or it can be used to describe a stable physical state.” (9)

Moreover, the caveats implicit here apply even more strongly when we shift our focus from basic body functions, and consider instead the realm of more ethereal human traits. What is the species-typical degree of kindness to strangers? How much intuitive sensibility is normal? What level of musical talent or literary flair typifies the human species? These are, as the scholar Eric Juengst points out, limitlessly beneficial psychosocial traits: there exists no ‘normal’ level beyond which we should stop seeking to cultivate – and yes, enhance – them. (10)  The more the merrier. Indeed, it is perfectly normal (!) to seek to boost these kinds of core human traits to ever-higher degrees.

It will not do, therefore, to conceptualize human enhancement as an alteration measurable against some sort of alleged universal benchmark of normal humanity. In some cases, as with the addition of wings, we can confidently assert that this is indeed a deviation from the species-typical. The same would be true if we decided to engineer a human with a body temperature of 55 degrees Fahrenheit. But with the majority of projected enhancements we will be discussing – chemical tools of mood control, memory chips, genetic alterations of physique or personality – the concept of ‘the normal’ needs to be treated with a great deal of circumspection. It can prove useful in certain limited contexts, but it can also lead us badly astray.

2. Enhancement vs. therapeutics or healing

We all know the difference between when we feel healthy and when we are sick. Experience has presumably also taught us that health and sickness are relative concepts, describing a range of mental states and physical conditions spread out along a spectrum. Somewhere along that spectrum, our condition deteriorates to a point at which we say to ourselves, “Dang, I’m catching a cold.” A little further along, we hit the trigger point for visiting the doctor. If we have a car accident on the way to the doctor, we may pass the threshold for accepting hospitalization.

Some bioethicists have sought to use this easily accessible concept of “a state of health” as a benchmark for discussing human enhancement. (11) According to this view, doctors and practitioners of biotechnology are justified in seeking to restore people to their customary state of well-being – repairing their wounds, healing their diseases, reversing the myriad malfunctions to which the human body is prone. But if they try to push their patients beyond that baseline state – tweaking or augmenting their physical or mental functions to levels higher than that person has ever experienced – they are entering a moral danger zone. Restoring wellness is good; seeking a condition “better than well” is wrong. (12)

Unfortunately, this treatment/enhancement distinction is fraught with serious conceptual problems. To begin with, the idea itself of “health” reflects many of the same ambiguities as the concept of normality. Some theorists define health negatively as a condition of freedom from disease; others (including the World Health Organization) adopt a positive definition: “a state of complete physical, mental, and social well-being.” (13) These competing definitions bear direct consequences for discussions of enhancement: the negative meaning leads to an emphasis on restoration of lost function, whereas the positive meaning opens the door for ongoing and potentially limitless improvements in a patient’s state.

Consider for example the following case. (14) Two 10-year-old boys, Johnny and Billy, arrive in a doctor’s office; both are short for their age, and both are seeking growth-hormone treatment to boost their height. The doctor carefully studies both boys, subjecting them to a battery of tests, and ultimately reaches the conclusion that they have exactly the same predicted adult height: five feet, three inches. The doctor, who feels a strong moral commitment to the treatment/enhancement distinction, declares that he is willing to prescribe the hormone to Johnny but not to Billy. Why? Because Johnny’s shortness is caused by a deficiency in growth hormone brought on several years earlier by a brain tumor: it therefore falls under the category of a disease. Billy’s shortness, however, has nothing to do with his hormone levels, which are normal; his stature simply reflects the fact that both his parents are also very short people, and he has inherited their genes. Since Billy has no disease, giving him growth hormone would amount to enhancing the height of a perfectly healthy person, and the doctor balks.

Unfair and unreasonable? Absolutely. These two boys will probably face equal amounts of social stigma, anxiety, and lost opportunities, in a society that (justifiably or not) prizes height in males. Why should they not be entitled to equal treatment? Yet these are the consequences of hypostatizing a concept of “ideal health” and then drawing a rigid line to say, “Here, but no further.” Such examples could be multiplied with regard to all manner of physical, mental, and emotional conditions.

The more sophisticated the practice of medicine becomes, the more often we (and our doctors) are likely to encounter these kinds of quandaries. As biotechnology increasingly allows doctors to intervene in fundamental biological processes, the act of healing becomes ever harder to dissociate from the possibility of enhancing. A psychiatrist prescribing Prozac; a neurologist wiring up a brain-computer interface that allows a paralyzed man to communicate; an immunologist using gene therapy to cure a patient afflicted by autoimmune deficiency – all these health professionals are deploying technologies that unavoidably open up the door to ever more potent forms of human enhancement. The same serotonin-reuptake mechanisms targeted by Prozac can be used to heal a chronically depressed individual or to dramatically augment the sense of well-being experienced by a healthy person. A brain-machine interface that allows stroke victims to control computers by thought can be readily adapted to allow healthy persons to control other machines (cars, warplanes, prostheses, robots) in exactly the same way. The techniques of somatic gene therapy can be used to reverse genetic diseases, but nothing in those techniques dictates an inherent restriction on which types of genes (and traits) we choose to modify. Where we can heal, we can also tweak, boost, augment. Where we can repair, we can also modify, redesign, reengineer.

The treatment/enhancement distinction, therefore, presents us with a moving target, because it is pegged to the concept of “health” – and the meanings of this latter word tend not only to vary between the negative and positive definitions, but also to shift from culture to culture and epoch to epoch. (15) This is not to argue, once again, that the distinction between treatment and enhancement is necessarily a worthless one. There exists a real qualitative difference between repairing my broken arm and surgically installing a bionic implant that allows me to throw a bocce ball 300 yards. Nevertheless, we need to remain acutely aware that, in using this distinction, we do not always stand on perfectly solid ground. In some instances the distinction proves useful, but in many other cases we will find ourselves amid the gray areas exemplified by the story of Johnny and Billy.

3. Enhancement vs. natural functioning

Some opponents of enhancement claim we should avoid it because it violates the natural order of things – either as given by God or (in a secular variant) as shaped through eons of evolutionary trial and error. Either way, they argue, we should not be tampering with the complex equilibrium that nature has bequeathed to us; we will pay dearly for our hubris if we do. (16)

The main problem with this position is that hardly anything remains “natural” in this rigorous sense in today’s world: one is hard pressed to find a single biological process going on anywhere on the planet (including within our bodies) that has not been altered in some substantial way by human intervention. From the ozone layer to the enzymes in my liver, the reach of human actions – and of the unintended but massive side-effects of human behaviors – have saturated the biosphere. This increasing “artificialization of the world” is an issue that environmentalists have been forced to confront over the past couple decades, and it arguably applies just as strongly to the human body as well. (17) What we eat and drink, the air we breathe, how we shelter ourselves, how we move around, how we communicate with each other – all these basic functions are permeated by artifice from start to finish.

Confronted with this observation, the proponents of natural functioning tend to fall back on a modified version of their argument. We have already done enough tampering with our world and our bodies, they argue: we should stop now and leave things as they currently stand. (18) There is wisdom in this conservative position, and we will return to it later in this book. Nevertheless, it is better to abandon the language of “nature” and “the natural” in pursuing this line of argument, for those are idealized concepts that bear little relevance to current physical and social realities. We live in a world permeated by natural-artificial hybrids of myriad varieties and stripes, and we may as well make our peace with this fact. Therefore, this conservative position can be more effectively framed as an argument about what kind of semi-artificial world we wish to inhabit, and which values we wish our intertwined machines and bodies and social networks and ecosystems to embody. When recast in this way, as a moral argument about preserving certain valuable forms of human relationships, certain precious aspects of human dignity, the caution and humility of the conservative position make good sense and should be taken seriously.

* * *

My purpose in this Appendix has been to show why we need to use the word “enhancement” with a certain amount of circumspection. In particular, we need to be aware of the tendency to embed this concept within stark binary oppositions that seem perfectly reasonable at first glance, but that in fact yield little more than conceptual muddles if they are not handled carefully. The idea of enhancement is often played off against concepts like “normal,” “healthy,” “therapeutics,” “species-typical,” and “natural,” as foils through which to define it. There is nothing inherently wrong with this; indeed, it is probably unavoidable, because these concepts form the necessary basis on which most discussions of medicine, technology, and human nature tend to take place.

The main problem lies in overestimating the clarity and fixity of these concepts. They are not worthless ideas, because in a great many cases they convey potent and useful meaning. A forest meadow is a more natural place than a city. A person with pancreatic cancer is less healthy than a person whose chief complaint is a tension headache. Wings are not part of the species-typical profile of humans. Nevertheless, it is important to be aware of the grey areas that characterize all these concepts, and to bear in mind the fact that, in many cases, we are really describing broad spectra of variation rather than straightforward, binary oppositions. Some of the resulting distinctions will be abundantly clear, and possess a quality of intuitive absoluteness that leaves us trenchantly confident. Others will elude all our best efforts to pin them down, and leave us with little more than a toss-up, a relative weighing of qualities irreducibly in tension with each other.


1. Justice Stewart’s opinion is cited on the following website:

2. Henry Greely, et. al, “Towards Responsible Use of Cognitive-Enhancing Drugs by the Healthy,” Nature456 (Dec. 2008), 702-705.

3. Results reported in AFP/Reuters article, April 10, 2008, available on the following website:

4. Greely, et. al., “Towards Responsible Use,” 702.

5. See the excellent discussion in Eric Parens, “Is Better Always Good? The Enhancement Project,” in Eric Parens, ed., Enhancing Human Traits: Ethical and Social Implications (Georgetown U. Press, 1998), 5-11.

6. James R. Flynn, “Massive IQ Gains in 14 Nations: What IQ Tests Really Measure,” Psychological Bulletin101:2 (1987), 171-91.

7. For a definition of retardation see the website of the American Association for Mental Retardation;

8. Flynn, “Massive IQ Gains,” 187.

9. Quoted in Anita Silvers, “A Fatal Attraction to Normalizing: Treating Disabilities as Deviations from ‘Species-Typical’ Functioning,” in Parens, ed., Enhancing Human Traits, 104-105.

10. Eric T. Juengst, “What Does Enhancement Mean?” in Parens, ed., Enhancing Human Traits, 29-47.

11. See Parens, “Is Better Always Good?”, 5-11.

12. See Leon Kass, ed., Beyond Therapy: Biotechnology and the Pursuit of Happiness. A Report by the President’s Council on Bioethics (Regan Books, 2003).

13. Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference, New York, 19 June – 22 July 1946. The definition is available on the following website:

14. I am adapting this vignette from the one given by David Allen and Norm Fost, quoted in Parens, “Is Better Always Good?”, 5-6.

15. Ruth Macklin, Against Relativism: Cultural Diversity and the Search for Ethical Universals in Medicine(Oxford U. Press, 1999).

16. For a discussion of the religious version of this argument, see Ronald Cole-Turner, ed., Design and Destiny: Jewish and Christian Perspectives on Human Germline Modification (MIT, 2008). For discussions of the secular version of the argument see Francis Fukuyama, Our Posthuman Future: Consequences of the Biotechnology Revolution (Farrar, Straus, 2002); and Michael Sandel, The Case Against Perfection: Ethics in the Age of Genetic Engineering (Harvard, 2007).

17. For a detailed discussion of this issue see Michael Bess, The Light-Green Society: Ecology and Technological Modernity in France, 1960-2000 (Chicago, 2003), chs. 13-15.

18. The most detailed articulation of this argument is given in Bill McKibben, Enough: Staying Human in an Engineered Age (Times Books, 2003).