Interview with Robert Bradbury
Questions by Sander Olson.
Answers by Robert Bradbury.
Robert Bradbury is a scientist
and software expert who has done groundbreaking research on ageing and
molecular nanotechnology. He has founded several companies and written
far reaching articles on the future of computation.
Question 1: Tell us
about your background. How did you first become interested in the concept
of molecular nanotechnology?
I studied computer science
at Harvard and spent around 15 years doing software development. I then
went back to school at the University of Washington and got an education
in molecular biology. During that process I became very interested in the
molecular biology of aging. It seemed to me that once we understood
the human genetic program completely we should be able to retard and eventually
stop aging, if we could apply patches to the genomic program. Sometime
during the early 90's, while studying these topics, I read "Engines of
Creation". Some of the ideas it contained gave me hope that we would eventually
have the means to modify the genetic program to end aging. Furthermore,
if reanimation following cryonic suspension proved feasible, it implied
that death was not the inevitable end for the billions of humans alive
today. So it served to focus part of my attention on the development of
molecular nanotechnology.
Question 2: You have
argued that extraterrestrial intelligences may be using "Matrioshka brains"
- computers the size of solar systems - how did this idea come about?
It was the result of a long
reasoning process about the hazard function to which humans with engineered
genomes would be subjected. If one studies the biology of aging,
one learns that the rate at which a species ages is determined in large
part by the hazard function for that species. Nature tunes genomes
for reproduction, not for longevity. Tom Kirkwood calls this the concept
of the "Disposable Soma Theory of Aging". Species with a high hazard function
age rapidly while species with a low hazard function age more slowly.
Thinking about the hazard function of non-aging humans made me realize
its very difficult to completely escape some hazards such asteroids and
nearby supernovas. In 1997 I realized that the only solution would seem
to be the development of a "distributed replicated intelligence". This
is analogous to companies that require very high reliability in computer
operations and to achieve that place redundant data centers in completely
different cities.
Around the same time I encountered
the idea of a "Jupiter Brain" on the Extropy Institute's mailing list.
This was a concept that had been discussed for several years as a "planetary
sized intelligent entity" that could be constructed by advanced civilizations.
The question arose as to whether a swarm of Jupiter Brains could effectively
utilize the entire power output generated by a star. Research seemed
to suggest that would not be the case so I invented the concept of a Matrioshka
Brain as an alternative computational architecture which would effectively
utilize the entire power output of a star. Briefly stated, a Matrioshka
Brains is a multi-layer swarm of orbiting satellites constructed using
molecular nanotechnology, utilizing all of the available matter in a solar
system to provide the greatest feasible computing capacity.
A Matrioshka Brain roughly
has the thought capacity of a trillion trillion human brains. So, if robust
nanotechnology allows mind uploading, as I believe will be the case, then
such an advanced computing architecture allows humans, even entire civilizations,
to evolve into "distributed replicated intelligences". The energy, matter,
computing and engineering capacity at the disposal of Matrioshka Brains
is so great that they can effectively trump the galactic hazard function.
Thus uploaded humans may evolve around the hazard function for a human
body and extend their average lifespan from thousands of years based on
engineered genomes to trillions of years or more.
Question 3: You appear
to be a supporter of the Drexlerian concept of nanotechnology. Yet
many scientists who are proponents of moving science to the molecular scale
are skeptical of the concept of molecular assemblers. What is your response
to Scientific American's most recent issue on nanotechnology?
I've written several critiques
of articles criticial of Drexlerian nanotechnology that people can read
for themselves. For example
see articles under http://www.aeiveos.com/~bradbury/Critiques/index.html.
Anyone who has studied molecular biology should have no problem with the
concept of molecular assemblers. They are called ribosomes. Drexler pointed
out natural systems in nature constitute an existence proof for molecular
nanotechnology in in 1981 PNAS article. I for one don't see why we are
still debating this other than the possibility that the skeptical scientists
simply haven't read the necessary literature.
Question 4: Whitesides
and Smalley argue that the tendency of atoms to stick together makes molecular
assemblers infeasible. Is this argument valid?
No. If we couldn't assemble
things an atom or molecule at a time then everything we see in nature would
not exist. Enzymes are perfect examples of special purpose molecular assemblers.
If there are questions regarding fesibility they relate to whether truely
universal assemblers that can assemble any valid atomic configuration can
exist. For example, can we produce a single assembler that can assemble
diamond, sapphire and titanium carbide at the molecular level or will three
different assembler architectures be required?
Question 5: You founded
Aeiveos to investigate the nature of ageing. Has your company made much
progress?
Aeiveos Corporation did some
research in Russia during the early 1990's. The results from that work,
led to a partnership with Tako Ventures called Aeiveos Sciences Group (ASG)
that started research in 1996 in the U.S. At that time two of our four
major projects were genotyping of centenarians to look for "longevity determinant
genes" and differential gene expression studies in mice of different ages
to understand the changes in gene expression that occur with age. We were
during that period the 2nd largest company, after Geron, conducting research
on the molecular biology of aging. Unfortunately it became clear by 1997
that the timing of that research effort was poor. Developing technologies
such as gene chips made it clear that much more information would be obtained
at a much lower cost by simply waiting a few years. I decided to separate
Aeiveos Corporation from ASG in late 1997. Subsequently Tako decided to
terminate the ASG research effort.
Today, one can see that my
foresight on these topics was fairly accurate. The first study using gene
chips in aging studies was made by Thomas Prolla and Richard Weindruch's
group in 1999. Another study was published by Stephen Spindler's lab in
PNAS September 4th 2001. Tom Perls, a professor at Harvard who was one
of the scientists with whom we were collaborating in 1996, published the
chromosome location for a possible longevity determinant gene on August
27th 2001. So information on the molecular biology of aging is starting
to evolve from a trickle to a flood.
Question 6: Isn't the
fundamental problem of ageing that our cells are programmed only to reproduce
a certain number of times? If we were to eliminate the telomeres, wouldn't
we all end up with multiple tumors throughout our bodies?
It seems accurate to say
that telomere shortening is one of the anti-cancer programs that appears
to be part of the human genome. It is also accurate that many (but not
all) cancer cells manage to turn on telomerase to lengthen their telomeres
to continue dividing. A side-effect of telomere shortening and its limits
on cell division may be aging in tissues where the cells continually divide
such as the skin, gut and immune system. This process doesn't, to me, seem
to be a very good explanation for aging in tissues where the cells are
not dividing such as most major organs, muscles and the neurons in the
brain. In those tissues a combination of free radical damage to mitochondria,
accumulation of undigestible molecules (e.g. lipofuscin), accumulated mutations
in DNA, and loss of cells due to apoptosis may all play a role. One thing
we know from the study of the evolutionary biology of aging is that there
will be no single cause of aging. There will be lots of flaws in our genetic
program that will need to be patched to extend human longevity.
Question 7: What technology
do you think stands the best chance of displacing silicon for future computers?
How long do you believe Moore's law will last?
Well, SiGe looks good for
a couple of years. Then the picture gets a bit fuzzier. Recent work from
ORNL (McKee, R. A. et al, Science 293:468) suggests that we may be able
to create MOS transistors using Ge alone. That would allow significant
unanticipated progress with regard to chip speeds. Motorola just announced
an entire suite of patents on methods that enable GaAs on Si. So
it looks like there are 3 competing technologies that will take Moore's
Law out to 2012 or so. That certainly provides ample time for molecular
electronics to ramp up to speed. One of the most interesting applications
may be if we see combined technologies. IBM's Blue Gene group mentions
the problem that they cannot put as much RAM memory as they would like
onto the Blue Gene chips. So, a strategy that could combine molecular electronic
memories, such as those being promoted by CALMEC and others, with SiGe
or GaAs chips could significantly increase our molecular modeling capabilities.
Question 8: Carbon
nanotubes show enormous promise, for both mechanical and electronic applications.
How extensively do you foresee carbon nanotubes being used?
Well, since we can manufacture
them now, people can actually develop applications using them. IBM's recent
molecular electronics announcements clearly shows that people are doing
just that. For robust macroscale applications its going to be necessary
to increase production volume, decrease production costs and deal with
quality control issues. I think that may take more than a few years.
Question 9: How extensively
do you see nanotechnology affecting society? Do you see nanotechnology
modifying and enhancing the traditional manufacturing base, or do you see
machine-phase nanotechnology completely replacing conventional manufacturing?
Right now, nanotechnology
is enhancing current methods. The "quantum dot" molecules, which are really
"quantum"-technology and not "nano"-technology, are being considered as
molecular labels in biotechnology applications. We have had fluorescent
labels for years, this type of "nano"-technology simply allows a refinement
of research methods by giving us more colors to work with. For example,
DNA sequencing machines that read DNA may be able to utilize 8 colors per
lane instead of the current 4 colors. That would double productivity.
Machine-phase nanotechnology
will replace traditional manufacturing only when we have very powerful
computers and the software to allow computer-aided-design of nanomachinery
has been developed. You certainly do not use humans to manage the placement
of the billions of atoms in a single nanorobot and you probably don't want
to use them to manage the millions of atoms in an assembler either. Human
design of an assembler is at the limit of what might consider "reasonably"
affordable. We must develop robust software tools and automated production
systems in order to achieve affordable manufacture of nanoscale parts and
systems.
Question 10: Many scientists,
such as Lyle Burkhead, argue that the best opportunity for working at the
atomic scale lies in using biological cells as miniature factories. What
do you think of this approach?
This is one of the best approaches
and I am currently circulating a business plan based on my ideas about
how this can be accomplished. I'll also be releasing a paper shortly that
details what I believe is a good overview of one path to molecular nanotechnology
based on this strategy. If one carefully considers Drexler's work such
as Table 16.1 in Nanosystems and his 1994 & 1995 publications, it is
clear that he has proposed progress along these lines as being one possible
path to robust molecular nanotechnology.
Question 11: What is
your opinion of the concept of a technological singularity - of artificial
intelligence? Do you believe it is feasible? If so, when do you believe
sentient machines will be built?
I think Vinge, Moravec and
Kurzweil have explored the topic of the singularity fairly well in their
articles and books. I think the idea that we get robust molecular nanotechnology
manufacturing capabilities (e.g. diamondoid assembly) and overnight we
get gray goo is silly. An enormous amount of design will need to go into
the creation of nanomachinery. CAD tools for nanomachinery will help and
we will gradually build increasing amounts of intelligence into the tools
but we do not get machines capable of intelligent design overnight! I think
Minsky's perspective on "artificial intelligence" is correct. It is a lot
of little programs with different strategies that have evolved at the hardware
and software levels that produce what we call "intelligence". I think he
also may have observed the fact that whenever we get a machine to do it,
we stop calling it "intelligent". When we fully understand the suite of
programs that humans use to produce intelligence, then I assume we will
be able to program machines to perform similarly.
In a sense we already have
"sentient" machines, if you mean sentience in the sense of self-awareness.
Lots of machines have sensors that can monitor their internal state and
respond to various conditions. William Calvin argues that we developed
this ability to a greater degree to allow the mental rehersal of strategies
such as rock or spear throwing. So you can consider sentience as the ability
to see yourself as the actor in a scene. It is now fairly standard practice
for chip companies to totally simulate the execution of a new CPU design
on other CPUs. Once we get to the point where the CPUs can observe the
simulation and alter its behavior, then I think we will be getting very
close to machine sentience. Of course it requires at least a Blue Gene
class machine to begin to approach human level sentience.
Question 12: What are
your plans for the future?
Well if the venture capitalists
buy my new business idea I'll be developing a company to do whole genome
engineering. If not, I'll probably go back to programming and wait for
the singularity to arrive. If I'm lucky I might manage to land a position
guiding the development of software for the design of proteins or enzymes.
I think that will provide the greatest leverage in accelerating the development
of robust molecular nanotechnology.
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