Beyond Computation: A Talk with Rodney Brooks
Rodney Brooks is trying to build robots with properties of living systems. These include self-reproducing and self-assembling robots and one inspired by Bill Joy that wanders around the corridors, finds electrical outlets, and plugs itself in. His students' edgy projects include real-time MRI imagery, virtual colonoscopies, programs that create DNA for E. coli molecules that act as computers, and eventually, self-organizing smart biomaterials that grow into objects, such as a table.
Originally published on Edge.org
June 5, 2002. Published on KurzweilAI.net, June 7, 2002.
Introduction
Rodney Brooks, a computer scientists and Director of the MIT's
Artificial Intelligence Laboratory, is looking for something beyond
computation in the sense that we don't understand and we can't describe
what's going on inside living systems using computation only. When
we build computational models of living systems, such as a self-evolving
system or an artificial immunology system -- they're not as robust
or rich as real living systems.
"Maybe we're missing something," Brooks asks, "but
what could that something be?" He is puzzled that we've got
all these biological metaphors that we're playing around with --
artificial immunology systems, building robots that appear lifelike
-- but none of them come close to real biological systems in robustness
and in performance. "What I'm worrying about," he says,
"is that perhaps in looking at biological systems we're missing
something that's always in there. You might be tempted to call it
an essence of life, but I'm not talking about anything outside of
biology or chemistry."
-- JB
RODNEY A. BROOKS is Director of the MIT Artificial Intelligence
Laboratory, and Fujitsu Professor of Computer Science. He is also
Chairman and Chief Technical Officer of iRobot, a 120-person robotics
company. Dr. Brooks also appeared as one of the four principals
in the Errol Morris movie Fast, Cheap, and Out of Control
(named after one of his papers in the Journal of the British Interplanetary
Society) in 1997 (one of Roger Ebert's 10 best films of the year).
He is the author of Flesh and Machines.
ROD
BROOKS' Edge Bio Page
ROD BROOKS: Every nine years or so I change what I'm doing scientifically.
Last year, 2001, I moved away from building humanoid robots to worry
about what the difference is between living matter and non-living
matter. You have an organization of molecules over here and it's
a living cell; you have an organization of molecules over here and
it's just matter. What is it that makes something alive? Humberto
Maturana was interested in this question, as was the late Francisco
Varela in his work on autopoesis. More recently, Stuart Kauffman
has talked about what it is that makes something living, how it
is a self-perpetuating structure of interrelationships.
We have all become computation-centric over the last few years.
We've tended to think that computation explains everything. When
I was a kid, I had a book which described the brain as a telephone-switching
network. Earlier books described it as a hydrodynamic system or
a steam engine. Then in the '60s it became a digital computer. In
the '80s it became a massively parallel digital computer. I bet
there's now a kid's book out there somewhere which says that the
brain is just like the World Wide Web because of all of its associations.
We're always taking the best technology that we have and using that
as the metaphor for the most complex things -- the brain and living
systems. And we've done that with computation.
But maybe there's more to us than computation. Maybe there's something
beyond computation in the sense that we don't understand and we
can't describe what's going on inside living systems using computation
only. When we build computational models of living systems -- such
as a self-evolving system or an artificial immunology system --
they're not as robust or rich as real living systems. Maybe we're
missing something, but what could that something be?
You could hypothesize that what's missing might be some aspect
of physics that we don't yet understand. David Chalmers has certainly
used that notion when he tries to explain consciousness. Roger Penrose
uses that notion to a certain extent when he says that it's got
to be the quantum effects in the microtubules. He's looking for
some physics that we already understand but are just not describing
well enough.
If we look back at how people tried to understand the solar system
in the time of Kepler and Copernicus, we notice that they had their
observations, geometry, and a. They could describe what was happening
in those terms, but it wasn't until they had calculus that they
were really able to make predictions and have a really good model
of what was happening. My working hypothesis is that in our understanding
of complexity and of how lots of pieces interact we're stuck at
that algebra-geometry stage. There's some other tool -- some organizational
principle -- that we need to understand in order to really describe
what's going on.
And maybe that tool doesn't have to be disruptive. If we look at
what happened in the late 19th century through the middle of the
20th, there were a couple of very disruptive things that happened
in physics: quantum mechanics and relativity. The whole world changed.
But computation also came along in that time period -- around the
1930s -- and that wasn't disruptive. If you were to take a 19th
century mathematician and sit him down in front of a chalk board,
you could explain the ideas of computation to him in a few days.
He wouldn't be saying, "My God, that can't be true!" But
if we took a 19th century physicist (or for that matter, an ordinary
person in the 21st century) and tried to explain quantum mechanics
to him, he would say, "That can't be true. It's too disruptive."
It's a completely different way of thinking. Using computation to
look at physical systems is not disruptive to the extent that it
needs its own special physics or chemistry; it's just a way of looking
at organization.
So, my mid-life research crisis has been to scale down looking
at humanoid robots and to start looking at the very simple question
of what makes something alive, and what the organizing principles
are that go on inside living systems. We're coming at it with two
and a half or three prongs. At one level we're trying to build robots
that have properties of living systems that robots haven't had before.
We're trying to build robots that can repair themselves, that can
reproduce (although we're a long way from self-reproduction), that
have metabolism, and that have to go out and seek energy to maintain
themselves. We're trying to design robots that are not built out
of silicon steel, but out of materials that are not as rigid or
as regular as traditional materials -- that are more like what we're
built out of. Our theme phrase is that we're going to build a robot
out of Jello. We don't really mean we're actually going to use Jello,
but that's the image we have in our mind. We are trying to figure
out how we could build a robot out of "mushy" stuff and
still have it be a robot that interacts in the world.
The second direction we're going is building large-scale computational
experiments. People might call them simulations, but since we're
not necessarily simulating anything real I prefer to call them experiments.
We're looking at a range of questions on living systems. One student,
for example, is looking at how multi-cellular reproduction can arise
from single-cell reproduction. When you step back a little bit you
can understand how single-cell reproduction works, but then how
did that turn into multi-cellular reproduction, which at one level
of organization looks very different from what's happening in the
single-cell reproduction. In single-cell reproduction one thing
gets bigger and then just breaks into two; in multicell reproduction
you're actually building different sorts of cells. This is important
in speculating about the pre-biotic emergence of self-organization
in the soup of chemicals that used to be Earth. We're trying to
figure out how self-organization occured, and how it bootstraped
Darwinian evolution, DNA, etc. out of that. The current dogma is
that DNA is central. But maybe DNA came along a lot later as a regulatory
mechanism.
In other computational experiments we're looking at very simple
animals and modeling their neural development. We're looking at
polyclad flatworms, which have a very primitive, but very adaptable
brain with a couple of thousand neurons. If you take a polyclad
flatworm and cut out its brain, it doesn't carry out all of its
usual behaviors but it can still survive. If you then get a brain
from another one and you put it into this brainless flatworm, after
a few days it can carry out all of its behaviors pretty well. If
you take a brain from another one and you turn it about 180 degrees
and put it in backwards, the flatworm will walk backwards a little
bit for the first few days, but after a few days it will be back
to normal with this brain helping it out. Or you can take a brain
and flip it over 180 degrees, and it adapts, and regrows. How is
that regrowth and self-organization happening in this fairly simple
system? All of these different projects are looking at how this
self-organization happens with computational experiments in a very
artificial life-like way.
Continued at: http://www.edge.org/3rd_culture/brooks_beyond/beyond_index.html
Copyright © 2002 by Edge Foundation, Inc.
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