Artificial brains are imminent...not!
Scientists are on the verge of building an artificial brain! How do I
know? Terry Sejnowski of the Salk Institute said so right here on
ScientificAmerican.com. He wrote that the goal of reverse-engineering
the brain—which the National Academy of Engineering recently posed as
one of its "grand challenges"—is "becoming increasingly plausible."
Scientists are learning more and more about the brain, and computers
are becoming more and more powerful. So naturally computers will soon
be able to mimic the brain's workings. So says Sejnowski.
Sejnowski is a very smart guy, whom I've interviewed several times
over the years about the mysteries of the brain. But I respectfully—
hell, disrespectfully, Terry can take it—disagree with his prediction
that artificial brains are imminent. Sejnowski's own article shows how
implausible his prediction is. He describes two projects—both software
programs running on powerful supercomputers—that represent the state
of the art in brain simulation. On the one hand, you have the "cat
brain" constructed by IBM researcher Dharmendra Modha; his simulation
contains about as many neurons as a cat's brain does organized into
roughly the same architecture. On the other hand, you have the Blue
Brain Project of Henry Markram, a neuroscientist at the Ecole
Polytechnique Fédérale de Lausanne.
Markram's simulation contains neurons and synaptic connections that
are much more detailed than those in Modha's program. Markram recently
bashed Modha for "mass deception," arguing that Modha's neurons and
synapses are so simple that they don't deserve to be called
simulations. Modha’s program is "light years away from a cat brain,
not even close to an ant's brain in complexity," Markram complained.
Talk about the pot calling the kettle black. Last year Markram stated,
"It is not impossible to build a human brain and we can do it in 10
years." If Modha's simulation is "light years" away from reality, so
is Markram's. Neither program includes "sensory inputs or motor
outputs," Sejnowski points out, and their neural-signaling patterns
resemble those of brains sleeping or undergoing an epileptic seizure.
In other words, neither Modha nor Markram can mimic even the simplest
operations of a healthy, awake, embodied brain.
The simulations of Modha and Markram are about as brain-like as one of
those plastic brains that neuroscientists like to keep on their desks.
The plastic brain has all the parts that a real brain does, it's
roughly the same color and it has about as many molecules in it. OK,
say optimists, the plastic brain doesn't actually perceive, emote,
plan or decide, but don't be so critical! Give the researchers time!
Another analogy: Current brain simulations resemble the "planes" and
"radios" that Melanesian cargo-cult tribes built out of palm fronds,
coral and coconut shells after being occupied by Japanese and American
troops during World War II. "Brains" that can't think are like
"planes" that can't fly.
In spite of all our sophisticated instruments and theories, our own
brains are still as magical and mysterious to us as a cargo plane was
to those Melanesians. Neuroscientists can't mimic brains because they
lack basic understanding of how brains work; they don't know what to
include in a simulation and what to leave out. Most simulations assume
that the basic physical unit of the brain is the neuron, and the basic
unit of information is the electrochemical action potential, or spike,
emitted by the neuron. A typical brain contains 100 billion cells, and
each cell is linked via dendrites and synapses to as many as 100,000
others. Assuming that each synapse processes one action potential per
second and that these transactions represent the brain's computational
output, then the brain performs at least one quadrillion operations
per second.
Computers are fast approaching this information-processing capacity,
leading to claims by artificial intelligence enthusiast Ray Kurzweil
and others that computers will soon not just equal but surpass our
brains in cognitive power. But the brain may be processing information
at many levels below and above that of individual neurons and
synapses. Moreover, scientists have no idea how the brain encodes
information. Unlike computers, which employ a single, static machine
code that translates electrical pulses into information, brains may
employ many different "neural codes," which may be constantly changing
in response to new experiences.
Go back a decade or two—or five or six—and you will find artificial
intelligence pioneers like Marvin Minsky and Herbert Simon
proclaiming, because of exciting advances in brain and computer
science: Artificial brains are coming! They're going to save us! Or
destroy us! Someday, these prophecies may come true, but there is no
reason to believe them now.
ABOUT THE AUTHOR
John Horgan, a former Scientific American staff writer, directs the
Center for Science Writings at Stevens Institute of Technology.
The views expressed are those of the author and are not necessarily
those of Scientific American.
Source: Scientific American
http://www.scientificamerican.com/blog/post.cfm?id=artificial-brains-
are-imminentnot-2010-05-14&sc=WR_20100520
On the Other Hand
Scientists are on the verge of building an artificial brain! How do I
know? Terry Sejnowski of the Salk Institute said so right here on
ScientificAmerican.com. He wrote that the goal of reverse-engineering
the brain—which the National Academy of Engineering recently posed as
one of its "grand challenges"—is "becoming increasingly plausible."
Scientists are learning more and more about the brain, and computers
are becoming more and more powerful. So naturally computers will soon
be able to mimic the brain's workings. So says Sejnowski.
Sejnowski is a very smart guy, whom I've interviewed several times
over the years about the mysteries of the brain. But I respectfully—
hell, disrespectfully, Terry can take it—disagree with his prediction
that artificial brains are imminent. Sejnowski's own article shows how
implausible his prediction is. He describes two projects—both software
programs running on powerful supercomputers—that represent the state
of the art in brain simulation. On the one hand, you have the "cat
brain" constructed by IBM researcher Dharmendra Modha; his simulation
contains about as many neurons as a cat's brain does organized into
roughly the same architecture. On the other hand, you have the Blue
Brain Project of Henry Markram, a neuroscientist at the Ecole
Polytechnique Fédérale de Lausanne.
Markram's simulation contains neurons and synaptic connections that
are much more detailed than those in Modha's program. Markram recently
bashed Modha for "mass deception," arguing that Modha's neurons and
synapses are so simple that they don't deserve to be called
simulations. Modha’s program is "light years away from a cat brain,
not even close to an ant's brain in complexity," Markram complained.
Talk about the pot calling the kettle black. Last year Markram stated,
"It is not impossible to build a human brain and we can do it in 10
years." If Modha's simulation is "light years" away from reality, so
is Markram's. Neither program includes "sensory inputs or motor
outputs," Sejnowski points out, and their neural-signaling patterns
resemble those of brains sleeping or undergoing an epileptic seizure.
In other words, neither Modha nor Markram can mimic even the simplest
operations of a healthy, awake, embodied brain.
The simulations of Modha and Markram are about as brain-like as one of
those plastic brains that neuroscientists like to keep on their desks.
The plastic brain has all the parts that a real brain does, it's
roughly the same color and it has about as many molecules in it. OK,
say optimists, the plastic brain doesn't actually perceive, emote,
plan or decide, but don't be so critical! Give the researchers time!
Another analogy: Current brain simulations resemble the "planes" and
"radios" that Melanesian cargo-cult tribes built out of palm fronds,
coral and coconut shells after being occupied by Japanese and American
troops during World War II. "Brains" that can't think are like
"planes" that can't fly.
In spite of all our sophisticated instruments and theories, our own
brains are still as magical and mysterious to us as a cargo plane was
to those Melanesians. Neuroscientists can't mimic brains because they
lack basic understanding of how brains work; they don't know what to
include in a simulation and what to leave out. Most simulations assume
that the basic physical unit of the brain is the neuron, and the basic
unit of information is the electrochemical action potential, or spike,
emitted by the neuron. A typical brain contains 100 billion cells, and
each cell is linked via dendrites and synapses to as many as 100,000
others. Assuming that each synapse processes one action potential per
second and that these transactions represent the brain's computational
output, then the brain performs at least one quadrillion operations
per second.
Computers are fast approaching this information-processing capacity,
leading to claims by artificial intelligence enthusiast Ray Kurzweil
and others that computers will soon not just equal but surpass our
brains in cognitive power. But the brain may be processing information
at many levels below and above that of individual neurons and
synapses. Moreover, scientists have no idea how the brain encodes
information. Unlike computers, which employ a single, static machine
code that translates electrical pulses into information, brains may
employ many different "neural codes," which may be constantly changing
in response to new experiences.
Go back a decade or two—or five or six—and you will find artificial
intelligence pioneers like Marvin Minsky and Herbert Simon
proclaiming, because of exciting advances in brain and computer
science: Artificial brains are coming! They're going to save us! Or
destroy us! Someday, these prophecies may come true, but there is no
reason to believe them now.
ABOUT THE AUTHOR
John Horgan, a former Scientific American staff writer, directs the
Center for Science Writings at Stevens Institute of Technology.
The views expressed are those of the author and are not necessarily
those of Scientific American.
Source: Scientific American
http://www.scientificamerican.com/blog/post.cfm?id=artificial-brains-
are-imminentnot-2010-05-14&sc=WR_20100520
On the Other Hand
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Simubot believes in Simulation