Death Is An Outrage

During the time that I’m speaking this sentence, a dozen people just died, worldwide.

There. Another dozen people have perished.

I think this is an outrage. I want to tell you why I think so, and what nanomedicine can do to help.

Slide 2

Let’s look at the dimensions of the human holocaust that we call “natural death.”

The death toll in the Year 2001 was worst in India. Almost 9 million casualties. The bodies were piled nearly as high in China. The United States fell in third, with 2.4 million fatalities. 21 nations lost over half a million lives, each. These 21 countries represented all cultures, races, creeds, and continents. The human death toll in the Year 2001 from all 227 nations on Earth was nearly 55 million people, of which about 52 million were not directly caused by human action, that is, not accidents, or suicides, or war. They were “natural” deaths.

Slide 8

Even the most widely recognized greatest disasters in human history pale in comparison to natural death. For example, the typhoon that struck Bangladesh in 1970 washed away a million lives. In 1232 AD, Genghis Khan burned the Persian city of Herat to the ground. It took his Mongol horde an entire week to slaughter the 1.6 million inhabitants. The Plague took 15 million per year, World War II, 9 million per year, for half a decade each. The worldwide influenza pandemic of 1918 exterminated less than 22 million people – not even half the annual casualties from natural death.

But natural death took 52 million lives last year. We can only conclude that natural death is measurably the greatest catastrophe humankind has ever faced.

Slide 14

Of course we’re outraged by natural death because of the obvious personal consequences. But the cost to humanity of our individual deaths is rarely appreciated, truly staggering, and equally heartbreaking.

Each one of us carries within us a complex universe of knowledge, life experience, and human relationships. Each individual is gifted with unique insights possessed by no one else. Almost all of this rich treasury of information is forever lost to mankind when we die. This lost treasury is truly enormous. If the vast content of each person’s life can be summarized in just one book, then every year, natural death robs us of 52 million books, worldwide. But the U.S. Library of Congress, the world’s largest collection of physical books, holds only 18 million volumes. So each year, we allow a destruction of knowledge equivalent to three Libraries of Congress.

Slide 17

It is as if in 2001, somebody burned the Library of Congress to the ground. Once in January. Then again in May. Then again in September. 52 million books go up in flames. And then in 2002, they burn it down again. Three more times. And then again in 2003.

What’s even worse is that if you agree with me that the sum total of each human mind would really fill many, many books, and not just one, then you must accept that the devastation of knowledge is actually far greater than I’ve suggested here.

Slide 18

Besides this staggering sacrifice of information, natural death also destroys wealth on a grand scale. According to the Lasker Foundation, a dozen or so studies since the mid-1970s have found the value for human life is in the range of $3 to $7 million dollars, using many different methodologies. More recently, Murphy and Topel at the University of Chicago drew this chart (which I’ve updated to Year-2000 dollars) showing the value of human life at every age. It recognizes that fewer years remain to us at older ages. But this is only half of the equation.

Slide 19

This chart shows estimates from the Census Bureau of the number of people that died in the United States in the Year 2000, in each age cohort, year by year. If you multiply the death rate at each age, from this chart, by the dollar value at each age, from the previous chart, you get the economic loss at each calendar age, due to natural death. The sum of these economic losses divided by the total number of deaths gives you the average economic value of a human life lost.

Slide 20

The result is an average value of about $2 million dollars for each human life lost. If we conservatively assume that the population age structure and the age-specific mortality is the same worldwide as in the United States, then the worldwide natural death toll of 52 million people in the Year 2001 represents an economic loss of about $100 trillion dollars. Every year.

How big of an economic calamity is this? Taking Federal Reserve figures for the total tangible wealth of the United States, including all financial assets, all real estate, and all consumer durables, net of debt, and applying the ratio of U.S. to world GDP gives us an estimate of total global tangible net worth of $91 trillion dollars. So this means that every year, natural death robs us of human capital equivalent in value to the entire tangible wealth of the world.

Slide 23

It is as if in the Year 2001, someone took out a giant broom and swept up all the physical assets of human civilization into a cosmic trash can, and then threw it all away. That’s $100 trillion dollars of financial assets, real estate, and durable goods. Gone. And then in 2002, the giant broom sweeps again. Another $100 trillion dollars of human capital is destroyed, or three times larger than the $33 trillion dollars of annual economic activity represented by world GDP. Then it happens again in 2003.

But the economic disaster caused by natural death is even worse, if you go back through history. Since the modern human species first emerged, perhaps 25 millennia ago, 34 billion people have ever walked the Earth, and 28 billion of us have already died. The equivalent total information waste is more than 28 billion books, enough to fill almost 2000 Libraries of Congress. The equivalent total economic waste is about $60 thousand trillion dollars, enough to rebuild our current tangible civilization 600 times over. If you carry the tally back a million years, to the very dawn of man, all these figures about double. Natural death is a disaster of unprecedented proportions in human history.

So ... what’s being done about this? Let’s take a statistical look at the progress to date.

Slide 24

This chart, compiled from Census Bureau data, shows that for the last one-and-a-half centuries, life expectancy at birth has risen dramatically in the United States. A newborn child in the Year 1850 could only expect to live to 38 years, but should reach almost 75 years today. To measure longevity, I’m using the Expected Age at Death, which is just your current age plus your remaining life expectancy.

But 20th century medical technology has mainly improved the longevity of the very young. Since 1850, the Expected Age at Death of a 40-year-old has only improved from 68 years to 77 years. The Expected Age at Death of a 70-year-old has only improved from 80 years to 83 years. In other words, a 70-year-old’s chances of living another 10 years were about as good in 1850 as they are today. Not much progress. But let’s take a closer look at the data.

Slide 26

This chart shows the rate of Change in Life Expectancy at birth since 1850, as measured in years of extra life expectancy achieved by medical technology per decade of calendar time. If we could get to a rate of 10 years of life extension per decade, then medical technology would be extending life exactly as fast as we’re aging, postponing natural death, on average, indefinitely. We see from the chart that the Change in Life Expectancy improved at only 1 year per decade up until 1890. After 1890, the Change in Life Expectancy of newborns jumped dramatically, reaching more than 6 years per decade at its peak in 1925. This was due to the rapid introduction of several basic medical breakthroughs, like public sanitation, comprehensive vaccination programs, and later, antibiotics.

Note that the rate of Change jumped from 0.8 to 4 years per decade during 1890 to 1900, a fivefold increase in a 10 year calendar span. The rate soared from 2 to 6 years per decade during 1910 to 1925, a threefold increase in a 15 year calendar span. So we know it’s possible to see very rapid increases in the rate of Change in Life Expectancy, when new technology is brought to bear on the problem. In other words, history tells us that the current 2.3 year per decade rate of progress could plausibly quadruple to the “magic” 10 years per decade threshold, in the space of just 10-20 years from today, if new resources and new medical technologies are focused on improving longevity.

Slide 27

Worried parents and life insurance salesmen often complain that the young think they’re immortal. Well, in a sense, the young are almost right! There are age groups for which it can validly be said that extreme life extension has already been achieved, using existing medical technology. To better appreciate this accomplishment, we need to talk about death rates for a few minutes.

The chart shows the aggregate death rate for all males, at all ages, in the United States, from 1850 to 2000. In 1850, each male had a 2 percent chance of dying in the next year. By 2000, each male had a 1 percent chance of dying in the next year. So over this 150-year time span, the death rate was cut in half. As a result,...

Slide 28

...the life expectancy from birth has approximately doubled, from 38 years in 1850 to almost 75 years in 2000, as shown by the black curve.

A very simple formula, written in red below, can be devised for estimating the Expected Age at Death. This formula encodes the simple truth that, roughly speaking, cutting the death rate in half doubles the life expectancy, as measured from the current age of the individual. The formula assumes a single net death rate, for a whole population of mixed ages. This is an important point, because the natural death rate in humans depends on our physiological age. Death rates typically rise with advancing age, except at the oldest ages.

Slide 29

Medical technology has had its greatest impact to date in preventing infant mortality, especially between the ages of 1 to 4. In the Year 1850, a young child in this age cohort had a 2.4 percent probability of dying in the next year. Today, the probability of dying in the next year for these children has been reduced from 2.4 percent to 0.04 percent. That’s a phenomenal 60-fold reduction.

What if future medical technologies permit us first to arrest, and later to reverse, the biological effects of aging? In such an era, our bodies would no longer tumble down a staircase of degeneration and frailty. Instead, our statistical death rate would take on some approximately fixed value that’s appropriate for our physiological-age cohort, not our calendar-age cohort. Biological age would no longer march in lockstep with calendar age. So, how much longer might we live, if we could just keep the bodies we had when we were young?

Slide 30

Well, in the Year 1850, the death rate for a U.S. male between the ages of 1 and 4 implied an Expected Age at Death, according to our formula, of only 31 years. That is, in 1850, a child that could remain perpetually 1-4 years old physiologically, would have died, on average, after 31 calendar years. Early childhood was still very unhealthy and dangerous in those days.

As medical technology slowly improved, childhood became far less dangerous. Most of the specific medical causes of early childhood death have now been analyzed, and conquered. As a result, a child that could remain perpetually 1-4 years old biologically today would not die, on average, until he or she reached the calendar age of 1800 years. Death would usually come from some form of non-medical accident, which is the leading cause of death up to age 44.

Of course, most of us aren’t 1-4 years old. How long would we live if we could halt any further biological aging of our bodies right now, at our current age?

Slide 31

Here’s the answer for various biological age cohorts up to 44 years old.

The 10-year-olds among us would fare the best, reaching an average Expected Age at Death exceeding 3000 calendar years. The 20-year-olds would make it to 600 calendar years. Life has even become less dangerous for the 40-year-olds, who could survive to an average calendar age of 300 years in today’s medical environment, if further biological aging could be immediately halted. These are remarkable achievements of medical technology compared to the Year 1850, a time when none of these groups would have survived more than 80-100 calendar years. Note that all of these curves – and most especially the youngest cohorts – began their steep climbs into extended longevity during the latter half of the 19th century.

Slide 32

If you’re over 45, the picture is not yet so bright. Non-aging biological 50-year-olds would live to a calendar age of 178 years. Non-aging 60-year-olds could only expect to survive to 113 calendar years in the current medical environment.

But the news is not all bad for the elders. The death rate for 80-year-old U.S. males fell by 45 percent during the last century. So some progress is definitely being made. The problem is that the absolute natural death rate is still so high among the elderly that the Expected Age at Death has not yet significantly improved.

Slide 33

Now, you remember those Expected Age at Death curves for the youngsters that began their steep climb into extended longevity in the late 19th Century? The biggest gains were in the 1-10 year old cohorts, where death rates fell 30- to 60-fold. These gains began at a time when this age cohort made up 20 to 30 percent of the U.S. population. Early deaths in this gigantic demographic bulge were of great concern to medical researchers at the time, who lavished their resources on solving this problem.

I think history is about to repeat, this time at the opposite end of the age scale. In the United States, people over 60 years of age already make up the single largest cohort at 16.5 percent, and this cohort grows to 20 to 30 percent of the U.S. population after 2015, and for decades beyond. As before, this demographic bulge will focus research scientists and research dollars towards solving the problem of premature death among the very old.

Slide 34

And there’s another societal motivation to reduce death rates. As nations become more industrialized, their birth rates go down. In the developed world, the birth-to-death ratio has been declining for decades. In many countries, there are already more deaths each year than births, which, in the long run, is a prescription for national extinction. To avoid a Population Implosion, these nations must get busy and reduce their death rates to below their falling birth rates.

Slide 35

The greatest advances in halting biological aging and preventing natural death are likely to come from the fields of biotechnology and nanotechnology. That is, nanomedicine. Nanomedicine is most simply and generally defined as the preservation and improvement of human health, using molecular tools and molecular knowledge of the human body.

In the near term, say, the next 5 years, the molecular tools of nanomedicine will include biologically active materials with well-defined nanoscale structures, such as dendrimer-based organic devices and pharmaceuticals based on fullerenes and organic nanotubes. We should also see genetic therapies and tissue engineering becoming more common in medical practice.

In the mid-term, the next 5 or 10 years or so, knowledge gained from genomics and proteomics will make possible new treatments tailored to specific individuals, new drugs targeting pathogens whose genomes have now been decoded, stem cell treatments to repair damaged tissue, replace missing function, or slow aging, and biological robots made from bacteria and other motile cells that have had their genomes re-engineered and re-programmed. We could also see artificial organic devices that incorporate biological motors or self-assembled DNA-based structures for a variety of useful medical purposes.



Molecular Parts

In the farther term, perhaps somewhere in the 10 or 20 year time frame, the first fruits of molecular nanorobotics should begin to appear in the medical field.

My own theoretical work in nanomedicine has concentrated on medical nanorobotics using diamondoid materials and nanoparts. This area, though clinically the most distant, and still mostly theoretical, may hold the greatest promise for health and life extension.

Many of you have probably seen the results of the early theoretical work done by Drexler and Merkle, including this collection of bearings, gears, and other possible nanorobot parts.

Neon Pump

Their most complex design was a nanoscale neon pump having over 6 thousand atoms, which was later simulated by computational chemists at CalTech. The pump impeller is at upper left. At lower left, the impeller is embedded in a chamber wall made of diamond. The CalTech simulation at right shows the neon atoms, rendered in blue, are slowly making their way through the device.

Building medical nanorobots in batches of trillions of devices cheaply enough to be practical for medical therapies requires some kind of manufacturing technology. There have been many proposals for molecular assemblers, tiny devices that could fabricate nanorobots with atomic precision. The video shows one approach to mass production, called exponential assembly, that has been proposed at Zyvex. Ralph Merkle and I are also working on a molecular assembler design of our own at Zyvex.

Respirocytes



What sorts of medical nanorobots could we build, and what would they do, if we could build them? The first device I designed was the respirocyte, an artificial red blood cell. I show them blue in color, because part of the outermost shell is made of sapphire, a ceramic which is almost as hard as diamond.

Natural red cells carry oxygen and carbon dioxide throughout the human body. We have about 30 trillion of these cells in all our blood. Half our blood volume is red cells. Each red cell is about 3 microns thick and 8 microns in diameter.

Respirocytes are much smaller than red cells – only 1 micron in diameter, about the size of a bacterium. Respirocytes are microscopic pressure tanks with a hull made mostly of flawless diamondoid crystal. These tanks could be safely charged up to 100,000 atmospheres of pressure, but we’ll be conservative and only run them up to 1000 atmospheres.

Respirocytes are self-contained nanorobots built of 18 billion precisely arranged structural atoms. Each device has an onboard computer and an onboard powerplant. But most importantly, molecular pumps are arranged on the surface to load and unload gases from the pressurized tanks. Tens of thousands of individual pumps, called molecular sorting rotors, cover a large fraction of the hull surface of the respirocyte.

© 2001 Phlesch Bubble Productions

We’re looking at a closeup of some rotors on the respirocyte surface. The oxygen molecules are in red, and the carbon dioxide molecules are in blue. Water solvent molecules aren’t shown. The diamond rotor is the fat black disk, and it rolls forward. As the rotor turns, CO 2 molecules drift into their binding sites on the rotor surface and are carried into the respirocyte interior.

Respirocyte Layout

There are 12 identical pumping stations like this one laid out around the equator of the respirocyte, with oxygen rotors on the left, carbon dioxide rotors on the right, and water rotors in the middle. Temperature and concentration sensors tell the devices when to release or pickup gases. Each station has special pressure sensors to receive ultrasonic acoustic messages, so doctors can tell the devices to turn on or off, or change their operating parameters, while the nanorobots are inside a patient.

Respirocyte Cutaway

The shaded area at left is the oxygen storage tank, the area at right is the CO 2 tank, the black dot at the center is the computer, and the open volume around the computer can be a vacuum, or can be filled or emptied with water. This allows the device to control its buoyancy very precisely and provides a crude but simple method for removing respirocytes from the blood using a centrifuge.

Respirocyte Animation, Part I and Part II

Robert A. Freitas Jr., “Exploratory Design in Medical Nanotechnology: A Mechanical Artificial Red Cell,” Artificial Cells, Blood Substitutes, and Immobil. Biotech. 26(1998):411-430. Abstract (HTML) ..... Paper (HTML)

We can’t build respirocytes today, but when we can build them, they could be used as an emergency treatment at the scene of a fire, where the victim has been overcome by carbon monoxide poisoning.

In this animation from the PBS documentary “Beyond Human”, 5 cc’s of respirocyte-containing fluid are injected into the patient’s vein. After passing through the pulmonary bed, the heart, and some major arteries, the respirocytes make their way into smaller, and smaller, blood vessels. After about 30 seconds, they reach the patient’s capillaries and begin releasing life-giving oxygen to starving tissues. In the tissues, oxygen is pumped out of the device by the sorting rotors on one side. Carbon dioxide is pumped into the device by the sorting rotors on the other side, one molecule at a time.

Half a minute later, when the respirocyte reaches the patient’s lungs, these same rotors reverse their direction of rotation, recharging the device with fresh oxygen and dumping the stored CO 2 , which can then be exhaled by the patient.

Only 5 cc’s of respirocytes, just 1 one-thousandth of our total blood volume, could duplicate the oxygen-carrying capability of the entire human blood mass. Each respirocyte transports hundreds of times more physiologically available oxygen molecules, than an equal volume of natural red blood cells.

A half a liter of respirocytes, the most that could possibly be safely added to our blood, would allow a person to hold his breath at the bottom of a swimming pool for up to 4 hours, or to sprint at top Olympic speed for up to 12 minutes, without taking a breath.

Microbivores

Robert A. Freitas Jr., “Microbivores: Artificial Mechanical Phagocytes using Digest and Discharge Protocol,” Zyvex preprint, March 2001. Summary Article (HTML) ..... Full Technical Paper (HTML)

Another medical nanorobot I designed more recently is the microbivore – an artificial white cell. There’s a 60-page paper online, with hundreds of literature references, if you want to read all the technical details – or you can find everything at rfreitas.com.

One main task of natural white cells is to absorb and digest microbial invaders in the bloodstream. This is called phagocytosis. Microbivore nanorobots would also perform phagocytosis, but would operate much faster, more reliably, and under human control. Like the respirocyte, the microbivore is much smaller than a red blood cell. But the microbivore is more complex than the respirocyte, having about 30 times more atoms involved in its construction. After I finished the microbivore scaling study, I worked with graphics artist Forrest Bishop to create most of the images you’ll see here.

Slide 50

We start with the hull design. The microbivore is a flattened sphere with the ends cut off. It measures over 3 microns in diameter along its major axis and 2 microns in diameter along its minor axis. This size helps to ensure that the nanorobot can safely pass through even the narrowest of human capillaries and other tight spots in the spleen and elsewhere.

The microbivore has a mouth, called the ingestion port, where microbes are fed in to be digested. The microbivore also has a rear end, or exhaust port. This is where the completely digested remains of the pathogen are expelled from the device. The rear door opens between the main body of the microbivore and a tail-cone structure.

Inside the microbivore, there are two concentric cylinders. The bacterium is minced into little pieces in the smaller inner cylinder, the morcellation chamber, and then the remains are pushed into the digestion chamber, the larger outer cylinder, In a preprogrammed sequence engineered digestive enzymes are added, then removed, using an array of sorting rotors. These enzymes reduce the microbe to simple chemicals – like amino acids, free fatty acids, and simple sugars.

But the first thing a microbivore has to do is acquire a pathogen to be digested. If the right bacterium bumps into the nanorobot surface, reversible binding sites on the microbivore hull can recognize and weakly bind to the bacterium. A set of 9 different antigenic markers should be specific enough, since all 9 must register a positive binding event to confirm that a targeted microbe has been caught.

There are 20,000 copies of these 9-marker receptor sets, distributed in 275 disk-shaped regions across the microbivore surface. These receptors are the multicolored dots you see around the perimeter of each disk. Inside the receptor ring are more rotors to absorb glucose and oxygen from the bloodstream for energy. At the center of each receptor disk is a grapple silo, which I’ll get to in a moment. Each disk is 150 nanometers in diameter.

Slide 56

Once a bacterium has been captured by the reversible receptors, telescoping grapples rise up out of the microbivore surface and attach to the trapped bacterium. The microbivore grapples are modeled after this watertight manipulator arm originally designed by Drexler for nanoscale manufacturing. This arm is about 100 nanometers long and has various rotating and telescoping joints that allow it to change its position, angle, and length.

Slide 57

But the microbivore grapples need a greater reach and range of motion, so they’re more complex, with many additional joints. We did some time and motion studies of the grapple arms.

In this first study [not shown], the grapple arm comes up through the microbivore surface. The end effector follows a linear path from right to left, roughly similar to the microbe transport motion we’ll be using. The grapple then retracts back into its silo.

In this second study [not shown], the grapple arm comes out of its silo and executes a complex twisting motion.

Here we show that adjacent grapple arms can physically reach each other, allowing them to hand off bound objects as small as a virus particle [not shown].

The frame on the left is a brief time and motion study [not shown] of the stereotyped motions that would be used by a succession of grapple arms, as they hand off a trapped microbe or virus particle from one grapple to the next.

The right frame shows how these grapple handoff motions can transport a large rod-shaped bacterium from its original capture site, forward into the mouth of the microbivore device [not shown]. The bug is rotated into the proper orientation as it approaches the open mouth.

Slide 64

Now I want to show you a real white cell in action. This video features a human neutrophil, the most common type of leukocyte or white cell, which is the large rectangular blob in the center of the scene. The neutrophil crawls between the spherical red blood cells, but there is also a Staph microbe on the film – the small dark dot near the upper left corner of the neutrophil. When I put the video [not shown] in motion, keep your eye on that microbe, because the viewing frame jerks around a bit to stay centered on the action.

The white cell detects the chemical effluents emitted by the bacterium, and gives chase. This movie is running about 10 times faster than real time. The neutrophil slides along at about 10 or 20 microns per minute, while ignoring the red cells. The leukocyte’s leading edge is stiff enough to deform the red cells and push them aside, as it bumps into them. At last, the white cell engulfs the bacterium. Although the final capture took only 30 seconds, complete digestion and excretion of the bug’s remains can take an hour or longer.

Now let’s see how the microbivore, an artificial white cell, does the same job [not shown]. Let’s say there are some rod-shaped bacteria floating in your blood. We inject an appropriate dose of microbivores.

A target bacterium binds to the surface of the microbivore, trapped by the reversible binding sites. Telescoping grapple arms emerge from silos in the nanorobot surface and anchor themselves to the microbe's outer coat, which is then released by the surface binding sites. The grapples transport the pathogen toward the ingestion port at the front of the device, where the cell is fed into the morcellation chamber. The microbivore’s mouth irises shut.Inside, the bacterium is mechanically minced, then forced into the digestion chamber where digestion is completed in just 30 seconds. The harmless remains are released back into the bloodstream through the rear of the device.

Our natural white cells – even when aided by antibiotics – can sometimes take weeks or months to completely clear bacteria from the bloodstream. By comparison, a dose of microbivores should be able to fully eliminate bloodborne pathogens in just minutes or hours, even in the case of locally dense infections. Microbivores would be up to ~1000 times faster-acting than natural leukocytes. They’d digest almost 100 times more microbial material than an equal volume of natural white cells could digest, in any given time period.

And even more powerful applications are possible.

Chromosome Replacement Therapy

Most diseases involve a molecular malfunction at the cellular level, and cell function is significantly controlled by gene expression of proteins. As a result, many disease processes are driven either by defective chromosomes or by defective gene expression. So in many cases it may be most efficient to extract the existing chromosomes from a diseased cell and insert new ones in their place. This procedure would be called “chromosome replacement therapy.”

In this procedure, your replacement chromosomes will be manufactured to order, outside of your body, in a clinical benchtop production device that includes a molecular assembly line. Your individual genome is used as the blueprint. If the patient wants, acquired or inherited defective genes could be replaced with nondefective base-pair sequences during the chromosome manufacturing process, thus permanently eliminating any genetic disease – including conditions related to aging. Nanorobots then install the properly methylated replacement chromosomes in every tissue cell in your body.

Slide 69

The end result of all these nanomedical advances will be to enable a process I call “dechronification” – or, “rolling back the clock.” I see no serious ethical problems with this. According to the volitional normative model of disease that is most appropriate for nanomedicine, if you’re physiologically old and don’t want to be, then for you, oldness and aging are a disease, and you deserve to be cured. After all, what’s the use of living many extra hundreds of years in a body that lacks the youthful appearance and vigor that you desire? Dechronification will first arrest biological aging, then reduce your biological age by performing three kinds of procedures on each one of the 4 trillion tissue cells in your body.

* First, a respirocyte- or microbivore-class device will be sent to enter every tissue cell, to remove accumulating metabolic toxins and undegradable material. Afterwards, these toxins will continue to slowly re-accumulate as they have all your life, so you’ll probably need a whole-body cleanout to prevent further aging, maybe once a year.

* Second, chromosome replacement therapy can be used to correct accumulated genetic damage and mutations in every one of your cells. This might also be repeated annually.

* Third, persistent cellular structural damage that the cell cannot repair by itself such as enlarged or disabled mitochondria can be reversed as required, on a cell by cell basis, using cellular repair devices.

We’re still a long way from having complete theoretical designs for many of these machines, but they all appear possible in theory, so eventually we will have good designs for them.

Slide 70

Using these annual checkups and cleanouts, and some occasional major repairs, your biological age could be restored once a year to the more or less constant physiological age that you select. I see little reason not to go for optimal youth – though trying to maintain your body at the ideal physiological age of 10 years old might be difficult and undesirable for other reasons.

A rollback to the physiology of your late teens would be easier to maintain and more fun. That would push your Expected Age at Death up to around 900 calendar years. You might still eventually die of accidental causes, but you’ll live ten times longer than you do now.

Slide 71

How far can we go with this? Well, if we can eliminate 99 percent of all medically preventable conditions that lead to natural death, your healthy lifespan should increase to about 1100 years. It may be that you’ll find it hard to coax more than a millennium or two out of your original biological body, because deaths from suicides and accidents have remained stubbornly high for the last 100 years, falling by only one-third during that time.

However, one can hope that the rate of suicides might be greatly reduced, with so much to look forward to, and with new nanomedical treatments for unhealthy mental states. Nanotechnology can also improve the overall safety of our material environment, leading to far fewer deaths from accidents.

Finally, genetic modifications or nanomedical augmentations to the human body may extend healthy lifespans still further, to a degree that cannot yet be accurately predicted.

Slide 72

In closing, I hope you’ll agree with me that natural death is an outrage. Indeed, it is humanity’s, and history’s, greatest outrage. Now, at long last, maybe we can finally do something about it. So let’s get on with it!

Thank you.

Last modified on 6 October 2005