Truly Human Enhancement: A Philosophical Defense of Limits

3. What Interest Do We Have in Superhuman Feats?

3 What Interest Do We Have in Superhuman Feats? The first years of the twenty-first century have seen a resurgence of the Hollywood superhero movie. A spate of big-grossing movies celebrates humans or humanlike beings with superhuman abilities. For example, the 2012 movie The Avengers features flying humans, humans with super-strength, humans sufficiently robust to survive skyscraper collapses, humans with the physical agility to dodge bullets, and humans with exceptional mental powers. Does the popularity of these movies suggest a perhaps only partially acknowledged desire to radically enhance our physical or mental powers? Should we pursue superhuman feats by means of genetic or cybernetic technologies? An interest in superhuman feats seems to conform to the objective ideal. The greater the degree of enhancement enabled by the application of genetic or cybernetic technologies to our bodies and minds, the more impressive will be our physical and mental feats. One way in which we value our capacities does conform to the objective ideal. Radical enhancement greatly increases the instrumental value of human capacities. There is, however, another kind of value that we attach to our capacities which follows the anthropocentric ideal. This mode of evaluation assigns increasing intrinsic value to enhancements of our capacities across and somewhat beyond the normal human range. Somewhere beyond that range it assigns decreasing intrinsic value. Radical enhancement brings the objective and anthropocentric ideals into conflict. Gains in instrumental value seem to entail sacrifices of intrinsic value. Perhaps we do not, as a practical matter, have to resolve this conflict by selecting either the objective or the anthropocentric ideals to guide our deliberations about enhancement. There are ways to procure many of the goods that track the objective ideal that do not involve enhancing 34 Chapter 3 human capacities. They are likely to be more effective at providing many of the goods that motivate the radical enhancement of human capacities. Furthermore, they do not reduce our capacities’ intrinsic value. The Value of Enhanced Marathons Haile Gebrselassie won the 2008 Berlin marathon in a world record time of 2 hours, 3 minutes, 59 seconds. His achievements have prompted intense debate in distance running circles about whether or when a human marathoner will run a sub-two-hour marathon. Here’s something that participants in this debate don’t consider themselves to be talking about. They don’t consider themselves to be debating whether the application of a genetic or cybernetic technology to an athlete might result in sub-two-hour marathons. The answer to this question is a pretty straightforward “yes.” Considered in objective terms, Gebrselassie’s performance is actually pretty mediocre. You would be unlikely to purchase a used car whose best performance over 42.195 kilometers was 2 hours, 3 minutes, 59 seconds. There are likely to be many ways of combining human brains and bodies with technology that would lead to marathons objectively superior to Gebrselassie’s. Consider a possible future technology that would radically enhance the endurance of human athletes and would enable marathons to be completed in times dramatically faster than 2 hours. One of the main limitations on the performances of competitors in the marathon is the amount of oxygen that can be carried to competitors’ muscles. Human athletes rely on hemoglobin to do this job. Injections of a synthetic version of the hormone erythropoietin (EPO) boost a competitor’s supply of hemoglobin . Consider one way in which the endurance of human athletes could be not only enhanced, but radically enhanced. Robert Freitas has described something he calls a respirocyte, a one-micron-wide miniature robot, or nanobot, designed as a replacement for hemoglobin.1 Respirocytes could boost endurance to levels far beyond those enabled by injections of EPO. They are currently mere theoretical entities. But should Freitas’s dreams be realized, respirocytes could be introduced into human bodies, dramatically outperforming hemoglobin in keeping our tissues oxygenated. Respirocytes would carry approximately 236 times the quantity of oxygen carried by the hemoglobin they replace. According to Freitas, a few cubic centimeters of them could “exactly replace the gas carrying capacity of the patient's What Interest Do We Have in Superhuman Feats? 35 entire 5.4 liters of blood.” He imagines that respirocytes could “enable a healthy person to sprint at top speed for at least 15 minutes without breathing , or to sit underwater at the bottom of a swimming pool for hours.”2 Such enhancements of endurance...