Our Impending Cyborg Future: A Pause for Reflection
Our Impending Cyborg Future: A Pause for Reflection
Much of the attention garnered by transhumanism revolves around its most expansive hopes for the technological enhancement of human life, and no such hope is loftier than immortality.
What kind of start toward that hope has nature given us? Natural selection has yielded bodies with robust mechanisms for homeostasis and self-repair. In most cases, those bodies survive in relatively good health through the years important for reproduction. But evolution is indifferent to the reliability of those bodies once our genetic legacy has been passed to our progeny. As we age, environmental challenges assail the smooth functioning of the biochemical â€œwheels within wheels.â€ Over time, our cells, and then our organs, succumb to those attacks. As others have noted, â€œWhile bodies are not designed to fail, neither are they designed for extended operation.â€1
Left by nature to deal with aging on our own, the simplest technological quest for immortality we might pursue could be based on three â€œRâ€™sâ€: Replace, Repair, and Rejuvenate. With the replacement strategy, if an organ wears out, then, like an old car, squeeze out a few more miles by swapping out an old part for a new one. Artificial tissues are already in use, and simple swap-outs of joints are common. Stem cells can be used to grow pieces of malfunctioning organs, and, in time, whole organs may be generated as replacements.
Yet, the organ that most clearly defines an individual cannot be swapped out for a new model. With 50 billion or so specialized cells, the adult human brain holds perhaps 100 trillion synaptic interconnections.2 The constantly changing pattern of those linkages defines your unique identity as a person, a tapestry whose weaving reflects your distinctive history.
To be worthwhile, then, one essential demand on any scheme for unlimited lifespan is that your brain must stay in good health so that your personhood remains intact. Even if other organs were swapped out to sustain a body indefinitely, who would want immortality if the purpose of that patchwork body was to sustain a hopelessly ravaged, minimally functional mind? So, the brain must be the ultimate strategic target for an immortality approach via repair or rejuvenation.
With the time limits imposed on this presentation, I will focus only on the genetic damage that mounts up in the brain with advancing years, ignoring other types of brain deterioration and all age-related damage to other organs. By age 70, most brain cells exhibit some of the hundreds of different genetic flaws impacting communication between neurons and the flexibility of the brain to learn and remember.3 With such widespread damage, much work has to be done to repair even one of the hundreds of types of defects. Myriads of microscopic repair agents would be needed to carry out a brain-wide restoration program via gene therapy, with each of those agents working with perfection, yet not triggering the bodyâ€™s immune system or causing other damage.
Those repair agents are unlikely to be nanoscale robotic machines with tiny cogs, wheels, and gears, the â€œnanobotsâ€ often speculated about. The warm, viscous interiors of cells, filled with jostling, sticky molecules, are miserable places for such devices, should they ever exist.4 As Richard Jones has suggested, â€œIt would be like making a clock and its gears out of rubber, then watching it tumble around in a clothes dryer and wondering why it doesn’t keep time.â€5
But nature already has solved the problem of working in such a messy environment. Our cells are already filled with biomolecular repair agents that find and fix damage, though those machines also become damaged and less efficient with age. So, if we want to fix age-damaged DNA in our neurons, a plan using specialized biomolecular machines is probably the best path.
Our repair and rejuvenation plan would proceed predictably: Determine a particular mode of gene damage to be repaired from the hundreds of types present. Construct a biomolecular repair agent specific to that type of damage. Embed that agent in an appropriate nanoscale transportation device â€“ say, encapsulated in a nanoparticle. Transport the repair agent through the blood/brain barrier to a target cell within a reasonable amount of time, without either having the repair agent altered or triggering a damaging response in or from the tissues.6 Finally, have the agent mend the damage within the target neuron with perfection. Repeat as necessary.
Even in this cartoon sketch of the process, the hurdles of specificity, mobility, efficiency, efficacy and reliability are profound at every step. For example, isolating and identifying the problem to be fixed already is difficult since some important neurological disorders involve more than one gene. At each step, difficulties compound each other. For a given genetic intervention, options that surmount one or several barriers might be found, but there is no a priori reason to assume that the combined requirements would leave any options available for every intervention.
To date, gene therapy research involving human subjects has resulted in only a few heroic trials at repairing different genetic disorders, none related to the brain.7 No approach based on gene therapy has been approved anywhere for routine treatment of age-related neurological damage. (Only China8 and the Philippines9 have approved gene therapies, and only for types of cancer.)
Realistically, then, achieving the level of repair needed for just the age-related genetic damage in our brains seems very remote within the next few decades, if ever. But an unwavering faith in technology can always translate the words â€œvery remote, if everâ€ into â€œsomeday.â€ If a usable 3-Râ€™s-technology might exist someday, a fourth â€œRâ€ could be added: Refrigerate. Vitrify and store the damaged brain at cryogenic temperatures, awaiting the day when those suitable new technologies arise.
Again, many obstacles are present. For instance, vitrification of a large organ like the brain inevitably generates many internal cracks and fissures. Each crack severs large numbers of synaptic interconnections. Even if a technology should appear in the distant future that could â€œre-wireâ€ these damaged links, the broken connections all look essentially the same, even at the molecular level. Re-weaving the torn tapestry would require an immense amount of guesswork.
In a frank display of caveat emptor, one cryonic preservation firm states on its web site â€œCryonics cannot be reversed by any simple means.â€ and â€œThere is still no definitive proof that cryonics can preserve long-term memory or personal identity.â€10 These terse warnings still seem generous. More accurately, we know of no means at all, simple or otherwise, how this process can be reversed, and no proof of any kind exists that human brain storage at cryogenic temperatures preserves any memories or identity at all. As Michael Schermer comments, cryonics â€œpromises everything, delivers nothing (but hope) and is based almost entirely on faith in the future.â€11
So far, the four Râ€™s weâ€™ve considered show little promise in making us immortal. Since our organic brains thus are headed towards decay, perhaps a fifth â€œRâ€ can provide a technological path to immortality: Replication. Capture the information-bearing pattern of your synaptic connections within a huge programmable array of transistorized logic gates, and then your consciousness will have been replicated in a new non-organic entity, and you (actually, the replicated one) will be as immortal as the substrate within which your consciousness has been embedded.
Or so the story goes. For â€œuploadingâ€ to work, consciousness must be nothing but the combined, moment-by-moment working-out of the interactions within the vast assembly of neurons, both with each other and with their environment. If this seems the â€œobviousâ€ answer to the question â€œWho am I?â€, we need to be honest and say that this answer assumes much. To get to this point, we must, for instance, forget (or forego) resolving the longstanding mind/body debate, wave off the manifold physiological and neurological contributions your body makes to your consciousness and sense of self, and also ignore all the ways your brain is different from a computer.
For the sake of argument, though, assume this account is correct. How practical will it be to accurately replicate your brain with a computer? If each synapse and its non-linear signaling functions could be replicated by as few as 100 transistors, then a single computer chip with maybe 10 million times more transistors than the chips manufactured today could do the job. If the number of transistors per chip doubles every two years or so as suggested by Mooreâ€™s Law, then we would have a single chip containing enough transistors by mid-century. Transfer the information pattern stored in your brain into this array of transistorsâ€¦ and then you would be immortal.
I will ignore the software issues involved with what it means to â€œuploadâ€ memories of, say, your first kiss. Instead, note that Mooreâ€™s Law is at root an economic observation about market forces in the semiconductor industry; it is not derived from fundamental science. Indeed, what science does say is that Mooreâ€™s Law is approaching the end of its applicability to silicon-based semiconductors. A few more doublings may occur over the next decade, but 20 more doublings over the next four decades will not. Other materials may be developed, but those materials likely will not move things far towards the 10-million-fold increase in components needed.
If quintillion-transistor-chips are not going to be available, we could hope some new computational paradigm might save us, but few options seem credible at this time. Quantum computing and DNA computing, sometimes mentioned in â€œuploadingâ€ discussions, may yet prove important for a number of applications, but replicating brains with those techniques does not appear to be a terribly good match. Both approaches require special environmental considerations for implementation that would make them unattractive for replicating a brain should they ever prove practical. Quantum computers, for example, need cryogenic environments12; eternally trundling around tanks of liquefied gas to keep your quantum brain cool sounds more like Hell than Paradise to me.
To sum up, the likelihood of extending the duration of any individualâ€™s consciousness indefinitely via technology seems negligible, and, in turn, I surmise technology will never make us immortal. This negative assessment is completely consistent with a position statement signed by 52 researchers in human aging which, after considering many possible approaches to stemming the effects of aging, said â€œThe prospect of humans living forever is as unlikely today as it has ever been, and discussions of such an impossible scenario have no place in a scientific discourse.â€13 While we will not achieve immortality through technology, progress still will be made on many fronts in our battle with aging. In the future, the declines and deficits to be faced with aging will be ameliorated or softened, but not altogether eliminated. Though far short of immortality, that is still an eminently worthy and (more to the point here) plausible pursuit.
My sincere appreciation for helpful and clarifying discussions and comments on this paper is extended to Arizona State University (ASU) colleagues Jeff Drucker, Stuart Lindsay, Michael Mobley, Norbert Samuelson, and Hava Tirsoh-Samuelson. The ASU Transhumanism Seminar was supported by a grant from the Metanexus Foundation.
Notes and References
1 Carnes, Bruce A. and S. Jay Olshansky. â€œA Realist View of Aging, Mortality, and Future Longevity,â€ Population and Development Review 33 (2007): 367-381.
2 Estimates of the total number of neurons and synapses in the brain vary widely based on a number of factors, including which parts of the brain should be counted towards the total. Estimates for the brain also explicitly ignore the similarly huge numbers of neurons in other parts of the body. For a popular level overview of the brain and brain research, seeThe Future of the Brain: The Promise and Perils of Tomorrowâ€™s Neuroscience, by Steven Rose (Oxford University Press, New York, 2005).
3 Lu, Tao, Ying Pan, Shyan-Yuan Kao, Cheng Li, Issac Kohane, Jennifer Chan, and Bruce A. Yanker. â€œGene regulation and DNA damage in the ageing human brain.â€ Nature 429 (2004): 883-891.
4 An accessible introductory book on nanoscale physics and the physical considerations regarding nanomachines isSoft Machines: Nanotechnology and Life, by Richard A. L. Jones (Oxford University Press, New York, 2004).
5 Jones, R. A. L. â€œRupturing the Nanotech Rapture.â€ IEEE Spectrum 45 (2008): 64-67.
6 The blood/brain barrier provides a significant additional hurdle for any gene therapeutic approach targeting the brain. See, for example, Norman R. Sanders, C. Joakim Ek, Mark D. Habgood, and Katarzyna M. Dziegielewska, â€œBarriers in the brain: a renaissance?â€ Trends in Neuroscience 31 (2008), 279-286.
7 Barlow-Stewart, Kristine. â€œGene Therapy.â€ Australian Genetics Resource Book, Fact Sheet 27. http://www.genetics.com.au/pdf/factsheets/fs27.pdf , accessed July 8, 2009.
8 Wilson, James M. â€œGendicine: The First Commercial Gene Therapy Product.â€ Human Gene Therapy 16 (2005): 1014.
9 â€œCurrent Gene Therapies.â€ Pharma Projects. http://www.pharmaprojects.com/therapy_analysis/genether_current_0409.htm , accessed July 8, 2009.
10 â€œScientistsâ€™ Cryonic FAQâ€. ALCOR Life Extension Foundation, http://www.alcor.org/sciencefaq.htm, accessed July 8, 2009.
11 Schermer, Michael. â€œNano Nonsense and Cryonics.â€ Scientific American 285 (2001): 29.
12 See, for example, Marshall Stoneham, â€œIs a room temperature, solid-state quantum computer mere fantasy?â€ Physics 2 (2009): 34-40.
13 Olshansky, Jay, Leonard Hayflick, and Bruce A. Carnes. â€œPosition Statement on Aging.â€ Journal of Gerontology: Biological Sciences 57A (2002): B292-297.