These are excerpts and elaborations from my book "The Nature of Consciousness"
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The British philosopher Andy
Clark, too, wants to bring back the body into the reasoning brain. We can dispose of the body
and still find ways that a brain would calculate how to perform actions, but
the very reason that we have bodies is that bodies make it a lot easier to
perform those actions even without calculating every single movement. The fact
that a body's movements are constrained by the body's structure is actually an
advantage: once the brain directs a general action, there are only so many ways
that the action can be carried out by the body. There is no need to calculate
ways that are beyond the capabilities of the body. Clark attacks the kind of Artificial
Intelligence that wants to equip machines with logic and "problem
solving" techniques (usually based on an abstract representation of the
world.) This is a way to build a brain without taking into account the body; a
very intelligent brain (possibly more intelligent than its creators) but
pathetically out of touch with the reality of its body and its possible
interactions with the environment. Clark, instead, envisions a road to artificial intelligence via
"autonomous agents", who are controllers of bodily action along the
lines of Rodney Brooks' "subsumption
architectures". They have simpler "brains", but their behavior
is largely driven by their interaction with the environment instead of pure
logic. Where logical systems take input from perception and calculate action,
these agents use action as perception. Thus the distinction between perception
and action fades away, as they are two sides of the same coin. And cognition
becomes simply the interaction with the environment, not a system of logic.
Learning occurs while we act. This, Clark reminds us, is more similar to the
"quick and dirty" strategies employed by Nature. All these theories of
"situated agents" that criticize the "problem-solving"
approach (the approach in which there is a "brain" planning
everything the body does) tend to miss an important point. They look at
biological organisms for inspiration, but they forget that biological organisms
evolve. Robots do not evolve (yet). That is the very basic reason that
Artificial Intelligence scientists came up with the need for a problem solver,
for an entity capable of solving every possible problem on purely logical
bases. Biological organisms embody their interaction with the environment:
their body has been sculpted by evolution to optimize that interaction. It is
hard to create a robot that can display the same degree of "fitness".
What we do not have (yet) is evolving robots: robots that, given an
environment, will build better and better fit robots. It is just very difficult
to have a robot build another robot. At best, we have software inside a robot
that evolves and fine-tunes itself. But that is not what happens in nature,
where it is the hardware itself (not just the software) that evolves. The
reason that Artificial Intelligence originally adopted the view of a
"disembodied brain" is that a robot "is" disembodied: it is
just a container for a mind. Our bodies are not mere containers of minds: our
bodies have been shaped by evolution to be the natural object and subject of
the mind. When Clark and Brooks build their robots, they commit
the same sin of the "problem-solving" crowd: they design the robot,
instead of letting evolution design it. The problem-solving crowd builds a
system that uses logic to decide behavior. Clark and Brooks use their own logic
(the logic of their brains) to design a robot that (according to their logical
thinking) will behave correctly in its environment. They have simply moved the
problem-solving activity from the brain of the machine to the brain of the
humans that design it. But nothing substantial has changed. Back to the beginning of the chapter "Ecological Realism: The Embodied Mind" | Back to the index of all chapters |
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