Download Whatever happened to machines that think?

Whatever happened to machines that think?
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23 April 2005
Justin Mullins
THE SINGULARITY: In futurology, a technological singularity is a predicted point in the development of a civilisation at
which technological progress accelerates beyond the ability of present-day humans to fully comprehend or predict. The
singularity can more specifically refer to the advent of smarter-than-human intelligence, and the cascading technological
progress assumed to follow.
Wikipedia - the online encyclopedia
CLEVER computers are everywhere. From robotic lawnmowers to intelligent lighting, washing machines and even car
engines that self-diagnose faults, there's a silicon brain in just about every modern device you can think of. But can you
honestly call any machine intelligent in a meaningful sense of the word?
One rainy afternoon last February I decided to find out. I switched on the computer in my study, and logged on to
www.intellibuddy.com, home to one of the leading artificial intelligences on the planet, to see what the state-of-the-art has to
offer.
Intellibuddy: Hi, I'm Intellibuddy!
Nice to meet you.
JM: I'm writing an article about artificial intelligence.
Intellibuddy: Will you include me in your essay?
JM: I will if you can persuade me you really are intelligent.
Intellibuddy: Would you recommend this action to a friend?
JM: Errr...are you intelligent?
Intellibuddy: Ummm I am highly intelligent. I have many intellectual functions.
JM: What are your intellectual functions?
Intellibuddy: Thought, reason, intelligence, logic and deduction.
JM: What is your IQ?
Intellibuddy: My IQ is about 250 in human terms.
JM: Wow, you're cleverer than my editor.
Intellibuddy: I'm glad your [sic] impressed, User.
You think I am cleverer than my editor.
JM: No, cleverer than my editor.
Intellibuddy: I'm glad your impressed, User.
You think I am cleverer than my editor.
JM: No, cleverer than my editor.
Intellibuddy: I'm glad your impressed, User.
You think I am cleverer than my editor...
So much for today's artificial intelligence. Intellibuddy is a version of one of the world's most successful chatbots, called
ALICE (Artificial Linguistic Internet Computer Entity) and invented in 1995 by Richard Wallace, an independent researcher
based in San Francisco. You can find versions of ALICE all over the web; the software is free. But whichever version you
choose to chat to, the results are disappointingly similar. While some conversations have promising starts, all descend into
the type of gibberish that only artificial intelligence can produce.
And it's not as if there hasn't been time to perfect the idea. The first chatbot appeared in the 1960s. Back then, the very idea
of chatting to a computer astounded people. Today, a conversation with a computer is viewed more on the level of talking to
your pet pooch - cute, but ultimately meaningless.
The problem with chatbots is a symptom of a deeper malaise in the field of artificial intelligence (AI). For years researchers
have been promising to deliver technology that will make computers we can chat to like friends, robots that function as
autonomous servants, and one day, for better or worse, even produce conscious machines. Yet we appear to be as far away
as ever from any of these goals.
But that could soon change. In the next few months, after being patiently nurtured for 22 years, an artificial brain called Cyc
(pronounced "psych") will be put online for the world to interact with. And it's only going to get cleverer. Opening Cyc up to
the masses is expected to accelerate the rate at which it learns, giving it access to the combined knowledge of millions of
people around the globe as it hoovers up new facts from web pages, webcams and data entered manually by anyone who
wants to contribute.
Crucially, Cyc's creator says it has developed a human trait no other AI system has managed to imitate: common sense. "I
believe we are heading towards a singularity and we will see it in less than 10 years," says Doug Lenat of Cycorp, the
system's creator.
But not all AI researchers welcome such claims. To many, they only fuel the sort of hype that spawned what became known
as the "AI winter" of the 1990s. This was a time that saw government funding for AI projects cut and hopes dashed by the
cold reality that making computers intelligent in the way we humans perceive intelligence is just too hard. Many scientists
working in areas that were once considered core AI now refuse even to be associated with the term. To them, the phrase
"artificial intelligence" has been forever tainted by a previous generation of researchers who hyped the technology and the
fabled singularity beyond reason. For them, the study of artificial intelligence is a relic of a bygone era that has been
superseded by research with less ambitious, more focused goals. Arguably, this has already led to a limited form of AI
appearing all around us. Elements of AI research are now used in everything from credit-scoring systems and automatic
camera focus controllers, to number plate recognition in speed cameras and spaceship navigation.
AI is in many ways as old as computing itself. The purpose of building computers in the first place was, after all, to perform
mathematical tasks such as code breaking that were too tough for humans to tackle. It was in 1950 that Alan Turing, the
celebrated second world war code breaker, mathematician and arguably inventor of the first computer, formulated the test
that would become the benchmark by which the intelligence of all computer programs would subsequently be measured (see
"Turing's test"). Even in Turing's day, computers were beginning to outperform humans in certain specific tasks. And as early
as 1948, John von Neumann, one of the fathers of the computer revolution, said: "You insist that there is something a
machine cannot do. If you will tell me precisely what it is that a machine cannot do, then I can always make a machine which
will do just that." It seemed just a matter of time before computers would outperform people in most mental tasks.
But many scientists and philosophers baulked at the idea. They claimed that there was something about being human that a
computer could never match. At first the arguments centred on properties such as consciousness and self-awareness, but
disagreement over what exactly these terms meant and how we could test for them prevented the debate from making any
real progress. Others admitted computers could become intelligent but said they would never develop qualities such as
compassion or wisdom which were uniquely human, the result of our emotional upbringing and experience. The definition of
intelligence itself began to slip through the philosophers' fingers, and the disagreements continue today.
Most researchers would at least encompass in their definition of AI the goal of building a machine that behaves in ways that
would be called intelligent if a human were responsible for that behaviour. Others would cast the definition even wider. Ant
colonies and immune systems, they say, also behave intelligently in ways that are utterly non-human. But to get bogged
down in the debate is to fall into the same trap that has plagued AI for decades. The Turing test is a reasonable yardstick.
We will know an intelligent machine when we can talk to one without realising it is a machine, and programs of Intellibuddy's
ilk clearly fall short of this requirement.
Intellibuddy is merely one of the latest in a long line of chatbots. In 1966 Joseph Weizenbaum, a computer scientist at the
Massachusetts Institute of Technology, developed the first chatbot, named Eliza after Eliza Doolittle, the character in George
Bernard Shaw's Pygmalion who is taught to imitate upper-class English speech. The program was designed to mimic a
psychotherapist and conversed with its patient mainly through a simple rhetorical trick: it reworded the patient's statements
as questions. For example:
Patient: I want to cry
Eliza: Why do you say you want to cry?
Patient: Because my mother hates me
Eliza: Who else in your family hates you?
...and so on. Eliza was programmed to spot key phrases in its interlocutor's sentences and plug them into preformed
sentences of its own. It was hugely successful. The idea of talking to a computer astounded people, and there are even
anecdotes of people developing emotional attachments to Eliza.
This early success contributed to a sense of optimism that the problems of AI could be overcome, much of it based on the
idea that some kind of grand unified theory of mind would emerge that would offer up a scheme to create artificial
intelligence on a platter. The late 1960s and early 1970s saw feverish speculation about the impact intelligent machines
might have on the world and the advantages they would bring to whoever developed them. The computer HAL in Stanley
Kubrick's classic 1968 movie 2001: A space odyssey summed up the visions being debated, and the fears they conjured up.
It was against this backdrop that Japan's Ministry of International Trade and Industry announced, in 1982, a programme
called the Fifth Generation Computer Systems project to develop massively parallel computers that would take computing
and AI to a new level. The scale of the project and its ambition were unprecedented and raised fears in the west that Japan
would end up dominating the computer industry in the same way it had taken the lead in the electronics and automotive
industries. If it developed truly intelligent machines there was no telling what Japan might be capable of.
An arms race of sorts ensued in which the US and Japan vied for supremacy. The US Department of Justice even waived
monopoly laws so that a group of American corporations that included giants such as Kodak and Motorola could join forces
to match the Japanese research effort. Between them they set up the Microelectronics and Computer Technology
Corporation (MCC) and asked Doug Lenat, then a computer scientist at Stanford University, to lead it. The Defense
Advanced Research Projects Agency (DARPA), the Pentagon's research arm, also began to take an interest, and injected
huge amounts of funding into the field.
But progress was frustratingly slow, and as the hoped-for breakthrough failed to materialise splits appeared between groups
taking different approaches. On one side were those who believed that the key to intelligence lay in symbolic reasoning, a
mathematical approach in which ideas and concepts are represented by symbols such as words, phrases or sentences,
which are then processed according to the rules of logic. Given enough information, the hope was that these symbolic
reasoning systems would eventually become intelligent. This approach appealed to many researchers because it meant that
general proofs might eventually be found that could simultaneously revolutionise several branches of AI, such as natural
language processing and machine vision.
Ignominious ending
But by the early 1990s, it had become clear that the Japanese project was not leading to any great leap forward in AI. Things
were no better in the US, as most of DARPA's projects failed to produce significant advances and the agency withdrew much
of its support. The repeated failures of these so-called expert systems - computer programs which, given specialist
knowledge described by a human, use logical inference to answer queries - caused widespread disillusionment with
symbolic reasoning. The human brain, many argued, obviously worked in a different way. This led to a spurt of enthusiasm
for new approaches such as artificial neural networks, which at a rudimentary level imitate the way neurons in the brain work,
and genetic algorithms, which imitate genetic inheritance and fitness to evolve better solutions to a problem with every
generation.
Neural nets got off to a promising start and they are now used in everything from computer games to DNA sequencing
systems. It was hoped that with sufficient complexity they could demonstrate intelligent behaviour. But these hopes were
dashed because, though neural networks have the ability to learn from their mistakes, all existing models failed to develop
long-term memory.
In the AI winter that followed, research funds became difficult to come by and many researchers focused their attention on
more specific problems, such as computer vision, speech recognition and automatic planning, which had more clearly
definable goals that they hoped would be easier to achieve. The effect was to fragment AI into numerous sub-disciplines. AI
as an all-encompassing field died a sudden and undignified death.
This fragmentation has had some benefits. It has allowed researchers to create a critical mass of work aimed at solving welldefined problems. Computer vision, for example, is now a discipline with its own journals and conferences. "There are
people who spend their whole careers on this one problem and never consider the other pieces of the puzzle," says Tom
Mitchell, an expert on AI at Carnegie Mellon University in Pittsburgh, Pennsylvania. The same is true of speech recognition,
text analysis and robot control.
Simple common sense
But Lenat refused to give up. As an academic he had been working on building a database of common-sense knowledge,
which he believed would be the key to cracking artificial intelligence. When funding for MCC dried up, he decided in 1994 to
go it alone and spin off a company called Cycorp, based in Austin, Texas, to continue the development of the AI system he
named Cyc.
The driving philosophy behind Cyc is that it should be able to recognise that in the phrase "the pen is in the box", the pen is a
small writing implement, while in the sentence "the box is in the pen", the pen is a much larger corral. Lenat reels off
examples where such common-sense distinctions can make all the difference. In speech recognition, the best way to
distinguish between the two spoken sentences "I've hired seven people" and "I fired seven people", which can sound
virtually identical, is to analyse the context of the conversation and what it means, rather than just look at the words in
isolation. "Humans would never have this problem, but a computer program might easily be confused," says Lenat. "There's
almost no area of AI that wouldn't benefit. It's the difference between usability and non-usability."
Cyc has been meticulously assembled to relate each fact to others within the database. It knows for example, that in the
sentence "each American has a president" there is only one president, whereas in the sentence "each American has a
mother" there are many millions of mothers. Cyc's knowledge is stored in the form of logical clauses that assert truths it has
learned. It is based on the symbolic reasoning systems that failed to deliver in the mid-1990s.
But Lenat and his team have made huge leaps since then. One of the curious things about Cyc is that the more it knows, the
more easily it can learn. The volume of common sense it has accumulated means it can begin to make sense of things for
itself. And every new fact that makes sense is incorporated and cross-referenced into its database. Lenat maintains that the
rate at which the system can learn depends on the amount of common sense it has about the world, and that today's AI
systems perform so badly because they have close to none. "The rate at which they can learn is close to zero," he says.
One of Cyc's most impressive features is the quality of the deductions it can make about things it has never learned about
directly. For example, it can tell whether two animals are related without having been programmed with the explicit
relationship between each animal we know of. Instead, it contains assertions that describe the entire Linnaean system of
taxonomy of plants and animals, and this allows it to determine the answer through logical reasoning.
Cyc now contains 3 million assertions. Impressive as that is, sheer numbers are not the point. "We are not trying to maximise
the number of assertions," Lenat says. Rather, he wants to limit them to the bare minimum that will allow Cyc to collect data
on its own. He says Cyc is getting close to achieving that number, and it is already advanced enough to query each input
itself, asking the human operator to clarify exactly what is meant.
Sometime this year it will be let loose onto the web, allowing millions of people to contribute to its fund of knowledge by
submitting questions to Cyc through a web page and correcting it if it gets the answers wrong. "We're very close to a system
that will allow the average person to enter knowledge," Lenat says. He envisages Cyc eventually being connected to
webcams and other sensors monitoring environments around the globe, building its knowledge of the world more or less by
itself.
When Cyc goes live, users should expect to get answers to their questions only some of the time because it won't yet have
the common sense to understand every question or have the knowledge to answer it. But with the critical mass looming, in
three to five years users should expect to get an answer most of the time. Lenat has pledged to make access to Cyc freely
available, allowing developers of other AI systems to tap into its fund of common sense to improve the performance of their
own systems.
Lenat's optimism about Cyc is mirrored by a reawakening of interest in AI the world over. In Japan, Europe and the US, big,
well-funded AI projects with lofty goals and grand visions for the future are once again gaining popularity. The renewed
confidence stems from a new breed of systems that can deal with uncertainty - something humans have little trouble with,
but which has till now brought computer programs grinding to a halt.
To cope with the uncertainty of the real world, the new programs employ statistical reasoning techniques: for example, a
robot might measure the distance to a nearby wall, move and make another similar measurement. Is it seeing the same wall
or a different one? At this stage it cannot tell, so it assigns a probability to each option, and then takes further measurements
and assigns further probabilities. The trick, of course, is to ensure that this process converges on a solution - a map of the
room. In practice these systems work most of the time, but the all too real fear is that the number of calculations could
explode far beyond the robot's capabilities, leaving it hopelessly confused. Ways of coping with these situations are currently
a hot topic of research.
Systems using the mathematical technique known as Bayesian inference have improved the performance of many AI
programs to the point where they can be used in the real world. The despised Microsoft Office paper-clip assistant is based
on Bayesian inference systems, as are pattern-recognition programs that can read text, or identify fingerprints and irises.
Other approaches to AI have produced specialist programs that have played, and occasionally beaten, world champions in
chess (New Scientist, 17 May 1997, p 13), draughts, and even poker (New Scientist, 20 December 2003, p 64).
But problems remain. Voice recognition only works usably in ideal conditions in which there is little or no background noise,
and even then its accuracy is limited (New Scientist, 9 April, p 22). Chess programs are only capable of beating humans
because the game itself can be reduced to a tree of possible moves, and given enough time computers are able to evaluate
the outcome of each sequence of moves to find the one that is most likely to lead to checkmate. In the game of Go the board
position is much harder for a computer to evaluate, and even modestly talented players can beat the most powerful
computer programs. Robots have trouble negotiating obstacles that a five-year-old can dodge with ease. And if Intellibuddy
is anything to go by, machines you can interact with, that understand what you are saying and react appropriately, are still
some way off.
It's in your head
Where could the secret to intelligence lie? According to Mitchell, the human brain is the place to look. He has been using
functional magnetic resonance imaging (fMRI) to see which parts of the brain become active when a person thinks about a
specific object. He has found that when people are asked to imagine a tool such as a hammer or a building such as a house,
the same areas of the brain are activated as when they are shown a picture of these objects. He has also found that the area
activated for each object - hammer or house - differs by a discernable amount depending on the object. "You can train a
program to look at the brain images and determine with 90 per cent accuracy whether that person is thinking about a tool or
a building," he says. Such a program could, eventually, literally read your mind.
For the moment the research is confined to concrete nouns associated with physical objects. Next Mitchell plans to see how
verbs make the brain light up, and beyond that whether the same areas light up when these nouns and verbs are
incorporated into sentences, or whether there is additional activation elsewhere in the brain. Mitchell hopes that this
approach will resolve the fundamental differences between the symbolic reasoning approach to AI, and biologically inspired
approaches such as neural nets.
The clue that Mitchell thinks is significant is that the same part of the brain seems to be responsible for both reasoning and
perception. So when thinking about a hammer the brain is acting like a symbolic reasoning system, and when recognising a
hammer the brain is acting like a neural network. "Knowing this could provide some guidance," says Mitchell. Exactly how
the designers of neural networks might use such findings is not yet clear. But Mitchell is convinced that this type of insight
from functional brain imaging is set to have a huge impact on the field.
Of course if Lenat's prediction proves true, by the time Mitchell's work bares fruit, Cyc may well have reached the singularity.
The history of AI suggests that is unlikely, but after decades of faltering starts and failed promises, things are beginning to
change. Finally, machines might soon start to think for themselves.
A brief history of AI
1936 Alan Turing completes his paper "On computable numbers" which paves the way for artificial intelligence and modern
computing
1942 Isaac Asimov sets out his three laws of robotics in the book I, Robot
1943 Warren McCulloch and Walter Pitts publish "A logical calculus of the ideas immanent in nervous activity" to describe
neural networks that can learn
1950 Claude Shannon publishes an analysis of chess playing as a search process
1950 Alan Turing proposes the Turing test to decide whether a computer is exhibiting intelligent behaviour
1956 John McCarthy coins the phrase "artificial intelligence" at a conference at Dartmouth College, New Hampshire
1956 Demonstration of the first AI program, called Logic Theorist, created by Allen Newell, Cliff Shaw and Herbert Simon at
the Carnegie Institute of Technology, now Carnegie Mellon University
1956 Stanislaw Ulam develops "Maniac I", the first chess program to beat a human player, at the Los Alamos National
Laboratory
1965 Herbert Simon predicts that "by 1985 machines will be capable of doing any work a man can do"
1966 Joseph Weizenbaum, a computer scientist at the Massachusetts Institute of Technology, develops Eliza, the world's
first chatbot
1969 Shakey, a robot built by the Stanford Research Institute in California, combines locomotion, perception and problem
solving
1975 John Holland describes genetic algorithms in his book Adaptation in Natural and Artificial Systems
1979 A computer-controlled autonomous vehicle called the Stanford Cart, built by Hans Moravec at Stanford University,
successfully negotiates a chair-filled room
1982 The Japanese Fifth Generation Computer project to develop massively parallel computers and a new artificial
intelligence is born
Mid-1980s Neural networks become the new fashion in AI research
1992 Doug Lenat forms Cycorp to continue work on Cyc, an expert system that's learning common sense
1997 The Deep Blue chess program beats the then world chess champion, Garry Kasparov
1997 Microsoft's Office Assistant, part of Office 97, uses AI to offer customised help
1999 Remote Agent, an AI system, is given primary control of NASA's Deep Space 1 spacecraft for two days, 100 million
kilometres from Earth
2001 The Global Hawk uncrewed aircraft uses an AI navigation system to guide it on a 13,000-kilometre journey from
California to Australia
2004 In the DARPA Grand Challenge to build an intelligent vehicle that can navigate a 229-kilometre course in the Mojave
desert, all the entrants fail to complete the course
2005 Cyc to go online
In his essay "Computing Machinery and Intelligence", published in the philosophical journal Mind in 1950, the British
mathematician Alan Turing argued that it would one day be possible for machines to think like humans. But if so, how would
we ever tell? Turing suggested that we could consider a machine to be intelligent if its responses were indistinguishable from
a human's. This has become the standard test for machine intelligence.
In 1990, Hugh Loebner, a New York philanthropist, offered a $100,000 prize for the first computer to beat the test and a
$2000 annual prize for the best of the rest. Past winners include Joseph Weintraub, three-time winner who developed The
PC Therapist, and Richard Wallace, the man behind ALICE, who has also won three times.
Printed on Fri Apr 22 08:14:34 BST 2005