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Prosthetic Technology and Human Enhancement: Benefits, Concerns and Regulatory Schemes Pt1
John Niman   May 2, 2013   Ethical Technology  

Prosthetic devices have helped restore functionality in humans who suffer from diseases requiring amputation or from limbs lost in battle for over three thousand years. I will begin this paper by explaining some of that historical journey. Next, I will highlight a few of the prosthetic devices available today to demonstrate that much, but not all, of that functionality can now be restored. Then I will explain what the future of prosthetic devices might look like if they faithfully adhere to Ray Kurzweil’s Law of Accelerating Returns.

In short, if Kurzweil is right then people may soon be able to replace their biological limbs with prosthetic devices that not only restore functionality, but improve upon the functionality of biological limbs. Indeed, Kurzweil makes a compelling argument that prosthetic devices will soon be more functional than biological limbs, and that even healthy humans will choose to replace their biological limbs with mechanical counterparts.

This 'enhancement technology' comes with some interesting ethical implications. I will explore some public policy arguments both in favor of and against voluntary replacement of human biological limbs. These concerns are relevant both to individual people and to society as a whole. Finally, I will conclude this paper by exploring some regulatory schemes that might reasonably apply to voluntary prosthetic enhancement, particularly tying this sort of surgery to already existing cosmetic surgery regulations.

Part I: The Plausibility of Prosthetic Enhancement

I.A: Historical Prosthetic Replacement

The Rig-Veda likely contains the first mention of prosthetic devices.1 This poem, published between 3500 B.C. And 1800 B.C., tells the story of an Indian queen fitted with a prosthetic leg after her own was severed in battle. Around 500 B.C. the Greeks also wrote about a prosthetic in Aristophanes' The Birds. By 215 B.C. one of the first actual prosthetic hands was fitted to Roman General Marcus Sergius after his own hand was lost in the Second Punic War.2 An artificial leg made of bronze unearthed in Italy dates back to around the same time.3

By 1508, prosthetic devices were not much better. German knight Gotz Von Berlichingen, or “Gotz of the Iron Hand”, was fitted with a prosthetic hand with movable fingers.4 The first moveable prosthetic leg was created around 1696.5 In 1898, Dr. Vanghetti created an artificial arm that could move through muscle contraction, though it seems the muscles themselves were attached to parts of the prosthetic device.6

Between 1900 and 1990 only a few notable advancements in prosthetic devices occurred. In 1912, the first aluminum prosthetic leg was fitted to aviator Marcel Desoutter.7 In 1946 a suction-socket attachment for below-the-knee amputees was created at UC Berkeley.8 Yet, after 1990 truly modern prosthetic devices began to develop as microprocessors and prosthetic limbs merged. Rather than recount the entire history of prosthetic devices between 1990 and 2013, it will be easier to give a broad overview of prosthetic devices currently available.

I.B: Modern-day Prosthetic Devices

The options for modern-day prosthetic replacement encompass more than simply arms and legs.9 Artificial hearts, inner ears, eyes, spleens, kidneys, pancreases, windpipes and more exist, though they rarely work as well as their biological counterparts.10 According to one source, 60% - 70% of a human has been effectively replaced by mechanical devices.11 For the purposes of this paper I will focus on bionic arms and legs, though I will occasionally mention other sorts of bionic upgrades that are possible, or will be possible shortly, as they are relevant.

The BeBionic prosthetic arm, which debuted in 2012, is one of the most advanced arms on the market today. It places sensors on the skin which, in conjunction with microprocessors in the arm itself, detect muscle movement from the remaining portion of the biological arm and translate patterns of movements into 14 different grips. This range of grips allows the user to grip a pen, type on a keyboard, hold keys or credit cards, wave, tie shoelaces, shake hands, and other tasks. The arm can hold up to 100 pounds of weight, grip objects with up to 31 pounds of strength, and comes in a range of designs from a flesh-like covering to carbon fiber or camouflage. At $25,000 - $35,000 this arm is relatively expensive.

While the BeBionic arm is one of the most advanced arms currently available, a new surgical technique suggests that even more advanced hands are on their way very shortly. Later in 2013 a man from Italy will undergo a first-of-its-kind procedure that allows people with new versions of prosthetic hands to feel sensation.12 By wiring the prosthetic arm directly into the median and ulnar nerves in the stump of the arm, and through those into the brain, a person fitted with this prosthetic hand can control the device more naturally and can also feel sensations. Amazingly, this is true even if the prosthetic arm is not directly attached to the person's body, but instead sits next to them.

Modern-day prosthetic legs are, in some ways, slightly behind their prosthetic arm counterparts – a trend that has been true in the past as well. There are not yet any reported trials connecting prosthetic legs to nerves to provide sensation. Prosthetic knees continue to bend, to the extent that they do at all, in only one direction. Prosthetic toes do not wiggle.

Yet, in other ways, prosthetic legs are more advanced than prosthetic arms. Prosthetic arms are generally multipurpose devices – they are intended to replace the functionality of a normal biological hand. Prosthetic legs also come in a multipurpose form. In addition, however, specialized prosthetic legs have begin to emerge that excel at particular tasks.

On the generic front, the Genium prosthetic leg is one of the most advanced on the market. The Genium is controlled by three sensors to detect muscle movement, and contains four microprocessors that determine the position of the leg when walking.13 The legs use a neural interface to replicate the function of biological leg muscles, and “automatically adjust to uneven ground such as stairs and ramps.”14 The powered knee replicates the thigh muscle, giving amputees the ability to climb stairs and stand up – tasks traditionally very difficult for above the knee amputees. Like the BeBionic arm, the Genium is very expensive (around 50,000 pound.)

On the specialized front, Oscar Pistorius' “blades” excel at running, allowing him to place within just a few seconds of the gold medal winner at the 2012 Summer Olympics. Other legs, like the carbon fiber set worn by Frenchman Phillippe Croizon, allow him to swim with what amounts to an attached set of flippers.15 Indeed, the legs allow Croizon to swim so well that he is planning to swim between every continent in the world. Truly, prosthetic devices have come a long way since Gotz's iron hand.

I.C: Future Advances

Ray Kurzweil offers one explanation for the advancement of prosthetic technology over the last 25 years, and also some reasons to think that these prosthetic devices will become much more advanced in the near future. Kurzweil has been studying technological trends for about 35 years, and has been inventing new devices since he was eleven. During this time, Kurzweil has discovered what he calls The Law Of Accelerating Returns (LOAR). LOAR posits that evolutionary technology, and in particular information technology, improves at an exponential rate.16

One reason for this is because technology is part of a positive feedback loop.17 Plainly speaking, we use the best technology currently available to build the next set of technology. Additionally, the more effective a technology becomes, the more resources are spent trying to further improve the technology.18 This results in what Kurzweil calls double exponential exponential growth – the technology itself becomes twice as efficient, and does so increasingly quickly. For example, at the beginning of the twentieth century it took about three years to double the price-performance of computing.19 During the middle of the twentieth century, it took only two years to achieve the same increase.20 This period of growth was called Moore's Law by IBM founder G.E. Moore. At the time The Singularity Was Near was published in 2005, the doubling time was further reduced to a single year.21

Because prosthetic devices now use microprocessors, sensors, and other forms of information gathering devices to control the prosthetic devices, these too are subject to the law of accelerating returns. Looking back at the historical progress of technology, supra, this trend is easily identifiable. At first, it took hundreds or thousands of years to significantly improve the functionality of human limbs. By the 1950's, prosthetic arms were slightly better than Gotz's iron hand, but not significantly more functional. In the 23 years since 1990, we have seen prosthetic devices move from basic placeholders for limbs with little functionality to sensation-transferring devices with multiple grips and legs so advanced that “disabled” athletes are able to compete with the very fastest “normal” humans.

Another key component of Kurzweil's theory is that the method used to increase technological capability is limited by the technology used to implement that increase.22 For instance, price-performance for computing was limited to some maximum amount when computers used punch cards, and then increased, but still limited, when they began to use vacuum tubes. When vacuum tubes gave way to transistors, price-performance increases resumed doubling regularly, and at a faster pace. Transistors are beginning to reach their maximum efficiency – when the transistors are packed only 35 carbon atoms apart, they will not be able to get any closer together.23 Fortunately, IBM and other companies are already transitioning to a new type of chip – 3-D computing (which replaces the current flat chip with a cube that places transistors both horizontally and vertically) which will allow the price-performance of computing to continue improving at an exponential rate.24

Like computer chips, prosthetic devices were limited by gear or pulley systems at first. Now, they are controlled by microprocessors and sensors, allowing for better fidelity. The newest prosthetic devices are wired directly into the nervous system, allowing (theoretically) for prosthetic devices that respond just as biological limbs do. In the near future, we may very well see prosthetic devices that respond at the maximum speed allowed by our biological nervous system. When that maximum speed is reached, we will need to integrate an upgraded method of data transfer to achieve yet faster results.

Part II: Individuals

II.A: Individual Benefits

Assuming that Kurzweil is correct, what sort of benefits might we expect from prosthetic devices with increasing fidelity to biological human limbs? The most obvious and easily accepted benefit of prosthetic limbs that operate as well as biological limbs is that “disabled” people (at least physically speaking) will cease to exist. While it is true that people will likely continue to lose limbs to combat, disease, and birth defects, these people will be able to replace their lost or defective biological limbs with technological analogues that work just as well. Oscar Pistorius, for instance, is able to run at speeds nearly rivaling Olympic gold medal winners on his prosthetic legs. Soldiers who have lost limbs in combat are now returning to the battlefield with prosthetic limbs after a year or so of rehabilitation.25 These are not soldiers returning in a diminished capacity. Instead, “the soldiers who are going back into battle are able to perform just as well, if not better, than some of their fellow soldiers.”26

Kurzweil, however, envisions something more profound. If prosthetic devices are able “only” to replicate biological functioning and must use the biological nervous system to communicate the best we might hope for is slightly improved functionality. We might, for instance, be able to replace our legs for specific tasks – donning one set with flippers for swimming and another for mountain climbing. We might, similarly, replace our arms with extendable versions for reaching higher, or install weapons in soldier's arms for combat.27

Yet, Kurzweil suggests that we ought to upgrade more of our body. Nanobots in the bloodstream can monitor our food intake, allowing our bodies only the nutrients we need and disposing of the rest by the 2020's.28 Redesigned blood cells, currently under development, will allow humans to survive for hours without oxygen, allowing us to deep sea dive or run at full on sprints for entire marathons.29 Similar robotic platelets could staunch bleeding up to 1,000 times faster, giving people incredible resiliency. Robotic white blood cells could vastly bolster our immune systems.30 Artificial hearts will become possible, but unnecessary with blood that propels itself.31 With the combination of oxygen-producing blood cells capable of self-propelled blood the lungs will likewise become unnecessary.32

Hormone producing organs and filtering organs like the kidneys, pancreas, thyroid, bladder, liver, bowels, and intestines will likewise become unnecessary.33 Gradual, non-invasive upgrades to the skeleton will become possible, resulting in self-healing or unbreakable bones.34 “Nanoengineered supple materials” will be able to replace the skin, providing for “greater protection from physical and thermal environmental effects while enhancing our capacity for intimate communication.”35 Only the brain will remain vital and that territory, too, is already being encroached upon by better functioning technological devices.36 For Kurzweil, there are no sacred cows.

Kurzweil is not alone in this vision. The President's Council On Bioethics in 2003 wrote a report focusing on the enhancement of human beings through technology.37 Fresh off the successes of the Human Genome Project, the Council understandably focused more on genetic enhancement than mechanical enhancement, though many of their thoughts are applicable to both sorts of enhancement. The Transhumanist movement, active since the 1980's but picking up more traction in the recent decade, has likewise taken to social media and academia alike to promote this vision of improving human beings through technology. Speaking of brain enhancement, a prominent Transhumanist, Giulio Prisco, recently wrote:

With the development of nanoscale neural probes and high speed, two-way Brain-Computer interfaces (BCI), by the end of the next decade we may have our iPhones implanted in our brains and become a telepathic species. Soon after, we may learn how to upload our minds to high performance engineered substrates and become a post-biological species of potentially immortal software minds.38

This sort of radical vision is common among Transhumanists, of which I consider myself a part. We have seen devices formerly in the science-fiction camp become reality, and we bring our passion for science-fiction to our scientific analysis. We have witnessed technology make amazing progress in other areas. We have watched wired phones become wireless, pagers become cell phones become smart phones, and Internet connection speed move from dial-up to DSL, cable, and now fiber optic. We have seen televisions move from bulky devices to flat screen wall hangings that display high definition three dimensional pictures, and VCRs become DVRs that we can access on our cell phones. There is little reason to think that the same progress will not be made with the human body. And, while it is probably too much to say that Transhumansists disrespect the human body, many of us do not hold it in any particularly high regard. It is a fantastic machine build by hundreds of thousands of years of trial and error coupled with random chance and the need to survive, but it could be better designed with modern-day materials and a purpose in mind.

And yet, while many Transhumanists envision a radically better future, most are not blind to the potential downsides of technological advancement. The radical changes Transhumanists envision are not necessarily good, and will certainly have dramatic effects on society and humanity as a whole. Before rushing headlong into this Transhumanist future, it is important to take account of these potential downsides, if only to better avoid their negative impact as much as possible.

II.B: Individual Concerns

The most obvious concern for individuals when augmenting themselves with technology is safety. It does little good to replace one's biological limbs with mechanical versions if the mechanical versions malfunction or otherwise are more of a hassle than their biological counterparts. While people missing limbs have replaced parts of their body with inferior technology for thousands of years (and, as good as the modern-day limbs are, continue to) these people are not choosing between a healthy biological limb and a mechanical limb, but instead between a highly defective biological limb, or often no limb at all, and a sub-par mechanical limb.

Safety concerns come in a number of varieties. The most basic concern is in the operation itself. No surgery is perfectly safe, and certainly not one that might remove up to half of the human body. While anesthetic and amputation methods have been greatly refined, deaths still occur. About 1 in 185,000 people die from anesthesia alone, though that number drops to 1 in 250,000 for healthy, middle aged adults.39 The amputation procedure itself is likely to carry a greater risk, but because amputations are not routinely carried out on healthy people with functional limbs I have not found any data on the exact risk. A heart surgeon recently told me that the risk of a heart transplant on an otherwise healthy person is “less than one percent.”40 Whether or not that same number applies to amputations, the National Health Service of England reports that the risk to patients of planned amputations is greater than the risk to patients of emergency amputations because planned amputations are often performed on older people with other complicating diseases.41

As prosthetic devices become more advanced, like the newest limbs that can be wired directly into nerves, additional risks are present. Whereas traditional prosthetic devices largely mount on the remaining portion of the amputated limb, these prosthetic devices are wired directly into the central nervous system. Nerve problems can run the gamut from transmission of pain signals that are potentially excruciating to deadening of nerve signals from electrical transmission. While it is likely that these sorts of problems will be overcome through more advanced techniques, the earliest adopters of this prosthetic technology are likely to experience these unforeseen consequences.

Assuming that the biological limb is amputated without indecent and the new limb is installed without complications, additional problems are likely to develop. No technology, even well-established technology, is without malfunction, and as limbs are increasingly controlled by software and other algorithms, the risk of malfunction becomes greater. When a laptop's hard drive crashes, it is an inconvenience. When a laptop suffers a critical failure, like a blown transistor or overheated processor, it is an annoyance. When a prosthetic limb malfunctions or breaks, a person is likely to have to undergo repair or replacement of the limb. This subjects the individual to yet more surgeries (though a repair of the limb itself might be a pain-free mechanical affair.) Yet, with limbs wired directly into the central nervous system, and potentially the brain, it is possible that catastrophic limb failures could be fatal.

Even assuming a perfect surgical replacement and a perfect limb, technological progress alone introduces some risk to patients. If Kurzweil is right and the exponential increase of technology continues, then prosthetic limbs will become outdated very quickly. A cutting-edge prosthetic limb in 2020 might well be half as efficient as a limb created in 2022, a quarter as efficient as a limb in 2024, and so on. By 2030, the limb will be something like 32 times less efficient. By 2040 the limb would be over 1,000 times less efficient. As an analogue, imagine trying to use a cell phone manufactured in 1995 on today's networks. Because cell phones are not connected to the body, they can be easily replaced. Replacement of a prosthetic limb is a much more complicated affair, and carries additional risks of surgical removal and replacement.

Material upgrades to prosthetic devices might be mitigated by software upgrades. As algorithms become more efficient, software updates might extend the life of a prosthetic limb for some time. For example, it is possible to run Windows 95 on a modern-day computer, but it is much more efficient to run Windows 7 or 8. This sort of software update, too, carries risks. If prosthetic limbs are to be updated wirelessly, like computers and cell phones, they are at risk of being hacked.42 Instead, it might be better to use a card or chip of some kind to manually update the software of the limb. This sort of hardware update is much more difficult for artificial hearts and organs inside the body when the user has no direct access to the organs. It is all but impossible for nanobot blood cells as Kurzweil imagines them. Perhaps an implant that connects all the prosthetic devices within the body to a central managing computer could be used, and that computer could connect to a limb or other external access port, but no plans for such a system are currently reported. Software updates carry the additional risk of being managed by companies seeking to make a profit. People who cannot afford to upgrade from Windows XP to Windows 7 run less efficient computers. People who cannot afford to upgrade the software on their artificial hearts may be at greater risk of death.

Safety is not the only concern when deciding whether to replace biological limbs and organs with mechanical counterparts. There may be some significant psychological harm in the process. For one thing, people replacing limbs and organs with mechanical parts are literally putting their lives in the hands of the device makers and software engineers. Many people cannot repair their own cars, much less write their own programming for their cell phones. Most people, on the other hand, have some understanding of how their bodies work and generally do not have to rely on other people to make sure their arm is functioning correctly. While it is true that we generally see a doctor when our biological body is malfunctioning, this seems like a similar problem that is different in kind: Namely, the day-to-day operation of our biological body is not updated in the same way that our cell phones and computers are.

The President's Council On Bioethics also highlighted some more philosophical problems with augmentation that might psychologically affect those who decide to upgrade. They worry about the degradation of the dignity of human activity – the satisfaction one receives from becoming, say, a skilled athlete or learned academic by using one's own merits and drive.43 Is it somehow “cheating” to use a mechanical pair of legs to run a marathon instead of building up the training and endurance needed to perform the same feat on human biological legs? The Council likewise identifies a problem similar to the previous problem – a loss of identity as more of our bodies become “outsourced” to the work of other people.44 In the Council's words:

As the power to transform our native powers increases, both in magnitude and refinement, so does the possibility for "self-alienation" - for losing, confounding, or abandoning our identity. I may get better, stronger, and happier - but I know not how. I am no longer the agent of self-transformation, but a passive patient of transforming powers.45


Finally, some have argued that humans can be exceptional only because they have flaws. Even if it were possible to engineer the human body to perfection (whatever that might mean for a particular person) it would not be desirable because we would somehow no longer be human. At the extreme, this could literally be true. Kurzweil puts forth a vision of fully mechanical bodies, with organs, blood, heart and brain replaced by mechanical analogues that are superior in function, but not biologically human. Prisco envisions disembodied software intelligences that are potentially immortal. Neither vision allows us to remain human.46

While benefits and risks run to the individual, replacement of limbs and organs also carries benefits and risks to society as a whole. While society is made up of individuals, the benefits and risks to society can be altogether different than the benefits and risks that accrue for a particular individual. It is those society-wide benefits and concerns that I now consider.


1See Earl E. Vanderwerker, A Brief Review of the History of Amputations and Prostheses, 15 ICIB 5, 15-16 (1976),



4See Chris Baker,. Prototype: Gotz of the Iron Hand – Fierce Knight, Fearsome Prosthetic, WIRED, June 28, 2011,

5See Kim M. Norton, A Brief History of Prosthetics, 17 INMOTION 7, (2007),

6See Mary Bellis, The History of Prosthetics, ABOUT, (last visited Apr. 25, 2013).

7Norton, supra note 5.

8Bellis, supra note 6.

9See, e.g. John Niman, Cyborg Possibilities – The Head (Part One), BOYDFUTURIST, Feb. 1, 2013,

10Id. See also John Niman, Cyborg Possibilities – The Torso and Skin (Part Two), BOYDFUTURIST, Feb. 3, 2013,, and John Niman, Cyborg Possibilities – Arms and Legs (Part Three), BOYDFUTURIST, Feb. 9, 2013,

11Corrinne Burns, How to build a bionic man, THE GUARDIAN Jan. 30, 2013.

12TECHNEWSDAILY, Touchy, Feeling Bionic Hand Closer to Reality, DISCOVERY Feb. 21, 2013,

13Paul Kendall, My close encounter with the bionic man, THE TELEGRAPH, Feb. 2, 2013,


15Kyle Wager, How A Man With No Arms or Legs Will Swim All Around The World, GIZMODO, Apr. 26, 2012,

16Ray Kurzweil, THE SINGULARITY IS NEAR 35-36 (2005).

17Id. at 40.

18Id. at 41.




22Id. at 42-43.

23Ray Kurzweil, Kurzweil Responds: Don't Underestimate the Singularity, MIT TECHNOLOGY REVIEW Oct. 19, 2011,

24These chips currently exist and are being tested. See Jon Fingas, University of Cambridge chip moves data in 3D through magnetic spin, ENGADGET, Feb. 3, 2013,

25Jason Koebler, New Prosthetics Keep Amputee Soldiers On Active Duty, US NEWS May 25, 2012,


27The Deus Ex: Human Revolution video game has some examples of this. The main character, Alex Jensen, has blades installed in his arms for “silent takedowns.” Other character have guns installed into their arns.

28Kurzweil, supra note 16 at 303-304.

29Id. at 305.

30Id. at 306.



33Id. at 307.



36Id. at 308.

37The President's Council On Bioethics, Beyond Therapy: Biotechnology And The Pursuit Of Happiness, Oct. 15, 2003,

38Giulio Prisco, The coming Golden Age of neurotech, INSTITUTE FOR ETHICS AND EMERGING TECHNOLOGIES, Mar. 18, 2013,

39Common Fears: How Likely Am I To Die?, ALLABOUTANAESTHESIA (last accessed Apr. 25, 2013).

40Interview with James Caccitolo M.D. in Tyler, TX. (Dec. 28, 2012).

41Complications of Amputation, NATIONAL HEALTH SERVICE, Nov. 07, 2012,

42See, e.g. Gregory Ferenstein, Hacked Pacemakers Could Send Deadly Shocks, TECHCRUNCH, Oct. 17, 2012,

43The President's Council On Bioethics, supra note 37 at 140-145.



46Consider, however, whether humanity qua humanity is necessarily a desirable end goal. If we remain the same person, but in a different, non-biological body, does the fact that our bodies are made up of atoms structured into biological organs necessarily hold some superior status to a body of atoms made into mechanical devices, or perhaps even to a mind of electrical signals not beholden to any particular atomic structure at all?

John Niman is an Affiliate Scholar, a J.D. Candidate at the William S. Boyd School of Law at the University of Nevada, Las Vegas. His primary legal interests include bioethics and personhood. He blogs about emerging technology and transhumanism at

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