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The Iconoclast
- CMU’s Hans Berliner was at the center of the
decades-long worldwide quest to build a computer that could beat a human chess
champion—a race that ended 15 years ago this spring
By Jason Togyer
Do you want to understand the history of computer
science? You might want to start with computer chess.
“If you look at the names associated with advances in
computer chess, you’ll find most of the people who founded the entire field of
computer science,” says Daniel Sleator, Carnegie Mellon professor of computer
science and a founder of the Internet Chess Club. Those pioneers include Alan
Turing; Ken Thompson, co-inventor of the Unix operating system; Claude Shannon,
inventor of information theory; John McCarthy, inventor of the LISP programming
language; and the founders of CMU’s computer science department, Allen Newell
and Herbert Simon.
Computer chess has been called the drosophila—fruit
fly—of artificial intelligence, or AI, research. If you’re studying genetics,
says Jonathan Schaeffer, a professor of computer science and vice provost of
the University of Alberta, you start with fruit flies, because they live, mate
and die in a few days, and multiple generations of a mutation can be observed
quickly.
“Chess—like the fruit fly—allows us to have a controlled
domain where we can experiment with lots of issues in intelligence,” says
Schaeffer, who led the team that designed Chinook, a computer checkers program
that seems to be unbeatable, and who also leads the university’s computer poker
research. “We start with something simple that we can understand, and once we
progress beyond chess, we move onto harder problems.”
One remarkable man spent two decades at the center of
computer chess research: CMU senior research scientist Hans Berliner (CS’75).
It was Berliner who built the first game-playing computer ever to defeat a
human champion and the first chess computer capable of playing at “senior
master” level, and it was Berliner who 15 years ago this May awarded the
Fredkin Prize in Artificial Intelligence to IBM’s Deep Blue—the machine,
designed by three CMU alumni, that defeated world chess champion Garry Kasparov.
Today, retired and living in Florida, Berliner is
characteristically blunt. Computer chess was “a research dead-end” as far as
artificial intelligence was concerned, he says.
“The whole
AI thesis was wrong,” Berliner says. “AI researchers thought more knowledge
would do everything.” As it turned out, more powerful processors and
machine-learning techniques powered by statistical analysis, not human-devised
rules, were able to crack data-intensive problems in speech, image analysis and
data retrieval.
But although computer chess may not have been the Rosetta
stone to understanding and simulating human intelligence, those who’ve studied
Berliner’s work say his research was no dead-end.
“He covered
a lot of ground, and he achieved excellence in all of those areas,” says Murray
Campbell (CS’87), one of the members of the IBM Deep Blue team.
“It would have been nice to say that computer chess led
to a huge breakthrough that allowed us to better understand human language or
translation, or led to a general model of human intelligence, but it didn’t,”
Campbell says. “It did lead to a change of mind, a change in attitude, about
how we approached a large number of problems in computer science. And in this
field—and this is an important point—Hans Berliner produced something that had
lasting value.”
Berliner “never took the easy way,” Schaeffer says. As a
result, Berliner “has a legacy of excellent papers that contain insights,
algorithms and new ideas that aren’t as common today as they should be. People
continue to reference his work when they realize there are other ways to do
things, and then they point at Hans.
“Most scientists aren’t willing to take the kinds of
risks that Hans would take,” Schaeffer says. “But that’s why his papers are
still around, while the papers of his contemporaries are long gone and
forgotten.”
# # #
Taking risks may be embedded in Berliner’s DNA. His
great-uncle Emile Berliner invented the gramophone—better known as the
phonograph. Although Thomas Edison generally gets credit for inventing recorded
sound, his cylindrical records were difficult to manufacture and store. Emile
Berliner perfected recorded discs—superior to Edison’s records in every way,
and arguably the predecessor of all formats that followed, including hard
drives and BluRay discs.
Another relative took a risk and rescued Hans Berliner
and his family from a potentially awful fate. Born in Germany in 1929, Berliner
entered public school just as Adolf Hitler was rising to power. The first hour
of each of his school days consisted of “religion” (meaning, “Christianity”)
and “National Socialism.” Berliner wasn’t allowed to participate in those
activities, and he couldn’t join his friends in the Hitler youth. “I was told
that I was Jewish, and they didn’t want me,” he says. “That was quite a shock,
and I guess that’s one of those things that sort of grows you up a little bit.”
Yet in other ways, Germany was a wondrous place—“probably
the best place in the world,” he says—for a child interested in science. “The
Germans were full of inventiveness and managed to produce things that were
very, very good,” says Berliner, who remembers having a metal wind-up car that
sensed when it was about to run off of a ledge and automatically steered away.
“This was a child’s toy with a real, working servomechanism in 1935 or
thereabouts,” he says. “I thought it was fantastic—and it was.” While
kindergarteners in the United States were finger-painting, Berliner and his
German classmates were probably “three years ahead” in mathematics. Those
formative years “had a very positive effect on me,” he says.
But the atmosphere in Hitler’s Germany promised nothing
except despair, and Berliner’s parents knew it. In 1936, two visitors from the
United States came to stay with the Berliner family. Seven-year-old Hans was
soon shocked to learn that the family was leaving Germany. A nephew of Uncle
Emile, Joseph Sanders, had arranged for about 10 members of the extended family
to emigrate to America.
Along with his family, Berliner arrived in the
Washington, D.C., area speaking very little English, and that with a thick
German accent. But he doggedly pursued his studies and would graduate high
school with the top grammar marks in his class. Years later, one of his fellow
students at Henry D. Cooke Elementary School, Mexican novelist and essayist
Carlos Fuentes, vividly remembered Berliner, the “extremely brilliant boy” with
“deep-set, bright eyes … a brilliant mathematical mind … and an air of
displaced courtesy that infuriated the popular, regular, feisty, knickered,
provincial, Depression-era sons-of-bitches.”
It was a rainy day at summer camp when a teen-age friend
taught Berliner to play chess. “I saw these kids doing this thing on a board,
and it wasn’t checkers, which I was pretty good at,” Berliner says. “So I
learned the moves, and by the end of the day, there was already someone I was
beating regularly. I like to say I was never the worst player in the world.”
Chess was a wonderful way to discipline his mind, Berliner says. “You’re forced
to deal with a certain level of reality,” he says. “It’s up to you to do
something that improves your prospects in a certain way. If you’ve trained
yourself and you have the proper machinery between your ears, you can think
quite far ahead.” By age 20, Berliner had achieved master status, winning the
District of Columbia Championship and the Southern States Championship.
Campbell, the 1977 Alberta chess champion, says Berliner
wasn’t a “star” player in the mold of Bobby Fischer or Garry Kasparov, but
achieved chess greatness “using a very systematic approach and a lot of hard
work.” Now a senior manager at IBM’s Thomas J. Watson Research Center in
Yorktown Heights, N.Y., Campbell says Berliner “had competitive fire” and an
analytical mind that enabled him to beat players “who might very well have been
more talented than him.”
While Berliner could evaluate chess moves six or eight
“plies” (one move by one player) deep, real-life proved trickier to navigate.
He remembers feeling adrift—that “the future was there, and you didn’t have to
do anything about it, because it would come to you.” After high school, he
entered George Washington University to pursue a degree in physics—“a
mini-catastrophe,” he says, because courses were taught by rote memorization,
and as his grades plummeted, the draft beckoned. Berliner served his time in
the U.S. Army with the German occupation forces. Throughout his tour of duty,
Berliner continued to play chess, including one exhibition where he kept eight
games going simultaneously against one of the top German teams—and won them
all.
Upon his return to civilian life, Berliner came back to
Washington determined not to re-enter college. Local lumber magnate Isador
Turover set Berliner straight. A fellow European immigrant who knew Berliner
through chess circles, Turover told the younger man in no uncertain terms, “You
will finish your degree.” Turover hired Berliner into his company so that he
could pay his way through GWU, though Berliner switched from physics to
psychology. “I was so naïve, I thought that when I got a degree in psychology,
I could hang out my shingle as a psychologist and start counseling people,” he
says. Again fate intervened. A classmate who worked at the Naval Research Lab
told Berliner, “We need people like you where I work.” Berliner wound up
working for the federal government on problems in what was then called “human
engineering” or “engineering psychology”—a predecessor to today’s studies of
interface design.
In chess circles, his ranking kept increasing—Berliner
represented the United States at the 10th Chess Olympiad in Helsinki and won
the 1953 New York State Championship, the 1956 Eastern States Open, and the
1957 Champion of Champions Tournament. By this time, he was playing games
blindfolded. “Two times, I think, I played six games at a time without sight of
a board,” he says. “Both times, I got an incredible migraine headache, so that
was not a smart thing to do.”
His reputation grew especially strong in correspondence
chess—games played through the mail—and from 1965 to 1968, Berliner was the
World Correspondence Chess Champion. His first championship is the stuff of
legends; Berliner won 12 of 16 and drew four times, giving him a margin of
victory three times better than any other winner. He remained the top-ranked
U.S. correspondence chess player until 2005, long after he stopped competing.
# # #
Though Berliner never considered making chess his
professional life, his career trajectory was less than fulfilling. From the
naval lab, Berliner went to Martin aircraft, General Electric and IBM. “My pay
was skyrocketing, but I had an awful lot of spare time,” he says. Nearing 40
and feeling frustrated, Berliner in 1967 met future Nobel laureate and Turing
Award winner Herb Simon at a technical meeting.
In 1956, Simon, associate dean of what was then known as
CMU’s Graduate School of Industrial Administration, had predicted (to his later
chagrin) that within 10 years a computer would become world chess champion. Two
years later, with Allen Newell and Cliff Shaw, Simon wrote one of the first
chess-playing programs, known as NSS. Berliner remembers being unimpressed with
NSS, which took up to an hour to make a move: “They could play against some
human who played even worse, but it couldn’t come close to beating a ranked
player.”
More than a decade later, Simon remained interested in
chess computers. He offered Berliner a job. Berliner turned him down. “If I’m
going to come there, you’ve got to put me on the student track,” he said.
“Who knows what my thinking was?” Berliner says now. “I
was at the point where I felt like I wanted to do something with my life—something
worthwhile.” Simon agreed and Berliner was accepted into CMU’s four-year-old
Computer Science Department, arriving in 1969 to find a “good” but “chaotic”
environment, “up on wobbly feet.” The department’s founding head, Alan Perlis
“was an amazing, wonderful person,” Berliner says. “He wasn’t perfect and he
wasn’t always right, but he had a desire for progress and truth that was very,
very commendable … he was sort of the guiding light for us and in a sense, the
lifeblood of the Computer Science Department.”
All new graduate students were expected to pass a
rigorous 24-hour take-home exam, the Extended Duration Qualifier. Berliner
found it impenetrable, but in the meantime, Newell allowed him to start his
thesis—“because I wanted to work on computer chess,” he says.
# # #
As far back as the 1940s, Alan Turing was pointing out
that if games can be described by a series of mathematical operations, and
computers can execute mathematical operations, then computers can play games
such as chess. In 1950, Turing wrote a rudimentary chess program, though he
lacked a computer capable of executing it.
Newell, Simon and Shaw’s chess program was an outgrowth
of their Logic Theorist, a program designed to prove the theorems of the
Principia Mathematica in a way that emulated human reasoning. Each problem was
represented as a tree, with a hypothesis at its “root” and each rule of
mathematical logic represented as a “branch.” If a rule was untrue for that
hypothesis, that branch was “pruned” and the program went to the next branch.
If a rule was proved true, the program went further down that branch to the
next operation. (Today, this is called “traversal” of a tree or graph.) In that
way, the program eventually arrived at a formal proof. Widely considered the world’s first
“artificial intelligence” program, Logic Theorist generated proofs for 38 of
Principia Mathematica’s first 52 theorems, including one that was simpler than
the commonly accepted proof.
For the next 20 years, search trees and “pruning”—using
heuristics—formed the basis for most AI programs. Programs that attempted to
play chess, generate proofs, or solve other problems by calculating all known
positions were derided as using “brute force”; top researchers like MIT’s
Claude Shannon declared flatly that brute-force methods would never work.
Chess is particularly useful for AI research because it’s
bounded by rules, unlike more abstract problems in speech or vision, Campbell
says. “It’s known to be a very challenging game, and it takes intelligence to
play it, yet it’s limited in very nice ways,” he says. “With chess, you don’t
have to ‘boil the ocean’ to make progress. You can focus on an interesting
subset and make some progress.”
Another of Berliner’s students, Carl Ebeling (CS’84), now
a professor of computer science at the University of Washington, says that many
problems in AI research rely on measurements, statistics and analysis, and the
results are hard to tease out. “In chess, it’s not hard to figure out if
something is working or not. You can’t B.S. people. If your program doesn’t
win, there may be a lot of reasons why it lost, but it’s hard to make excuses.”
Alberta’s Schaeffer adds that if a researcher is trying
to build an “intelligent” machine, “and it can’t even play a simple game such
as chess, then clearly you have a long way to go.” In the 1970s, when Schaeffer
was beginning his own studies in computer science, “chess was the game, par
excellence, that everyone was researching, and when you looked at the
high-quality scientific venues, the premier journals, there was only one person
in the entire community who was publishing there, and that was Hans Berliner.”
# # #
Berliner’s first chess program was also his first
computer program of any kind. Written at IBM on his own time, it was called “J.
Biit”—“Just Because It Is There.” J. Biit came to CMU with Berliner and was an
early favorite to win the first North American Computer Chess Championship, but
it lost to Northwestern University’s Chess 3.0. His next program, written as he
worked on his doctoral thesis, titled “Chess as Problem Solving,” remembered
the errors it had previously made and learned to avoid them before beginning a
new search. Yet even as Berliner refined the program, called “CAPS,” he became
convinced that rule-based chess programs weren’t enough to defeat a human
champion.
Although their goal was to imitate human decision-making,
they left no room for intuition or guesswork. “I had a set of rules that were
limited,” Berliner says. “They were the most important things—maybe 80
percent—but that’s nothing. The other 20 percent includes the things the top
players know how to do. That’s why they’re the top players.” Newell and Simon
kept pressing Berliner to push onward: “Allen would say, ‘you’re not trying
hard enough—you’ve got to make up more rules.’”
As he looked for a new avenue for his research, Berliner
learned the game of backgammon from his father-in-law. Simpler than chess,
backgammon requires both luck and strategy; players start with their checkers
stacked at three different points on the board and move them based on rolls of
the dice, and the first player to move all of his or her checkers off the board
wins. Berliner decided to write a backgammon program. At first, it would get to
a certain point and then start to bog down. “It kept trying to optimize things
that it should have forgotten about,” he says. “At some point, you’re not just
winning, you’ve actually won, and your strategy should change at that point—you
should be aware that a transition is coming.”
Berliner hit on the idea of using fuzzy logic—still a new
concept in the 1970s—to assign different rules “weights,” or “application
factors,” based on their relative importance at each stage of the game. Now,
the program, called BKG, started winning games it would have previously lost.
In July 1979, it became the first computer program to beat a reigning world
champion in any game when it defeated backgammon player Luigi Villa. Despite
the success, Berliner found himself pigeonholed. One of his papers on BKG was
returned by an AI conference with a note from a reviewer: “Why isn’t Berliner
working on chess?”
But Berliner was working on chess. “A lot of the work in
computer chess was ad hoc—it was done by hobbyists for fun, and never got
published,” Schaeffer says. “Hans was a scientist, first and foremost. He
tackled chess with scientific rigor, and as he discovered new ideas or
insights, he published them properly—not in weak, mediocre conferences, but at
the top, in the premier journals and conferences.”
Campbell was drawn to CMU on the strength of Berliner’s
research in chess. “I read some of his papers, and that was where I wanted to
be,” he says.
# # #
One of the highlights of Berliner’s research in those
years was the B* (“B-star”) algorithm, designed to emulate what he calls the
“jumping around” process in human thought. Most tree searches were performed
either best-first or depth-first. Best-first searches find the lowest-cost path
to a goal, going from branch to branch as necessary, while depth-first searches
explore every branch on a tree to its end until reaching a goal. As Berliner
saw it, both searches had serious drawbacks—depth-first searches wasted time,
while best-first searches required a lot of effort to keep track of alternate
paths. Perhaps the worst problem—from his perspective—was that both searches
were strictly goal-oriented. They had to be arbitrarily terminated or else they
would keep trying to reach a goal, bypassing “good enough” paths while trying
to find an optimal solution. Like the first version of Berliner’s backgammon
program, they didn’t know when to quit.
The answer came to Berliner in the middle of the night.
Rather than writing an algorithm that searched a tree based on hard-and-fast
limits, Berliner’s B* algorithm assigned an “optimistic” and a “pessimistic”
score to each node. The algorithm kept searching a branch as long as the pessimistic
value of the best node was no worse than the optimistic value of its sibling
nodes. B* found paths that were sufficient to a task rather than theoretically
“perfect” ones—emulating the way that a human chess master will stop when she
or he finds a move that seemed to be clearly the best.
“B* tried to use the power of computers to search in a
way that was like a rational human being would search,” says Andy Palay
(CS’83), now at Google. Unlike simple A* “best-first” searches, B* is “a much
more directed search toward what appear to be the most promising paths,” says
Palay, who wrote his doctoral thesis on ways of extending the B* algorithm
using a probability distribution rather than upper and lower (“optimistic” and
“pessimistic”) values.
It was Palay who suggested applying B* to chess. There
are between 30 and 60 legal moves at any given point in a chess game, and
searching for those legal moves consumed up to 75 percent of a chess computer’s
time. In a chess tournament, each player is allowed an average of only three
minutes to make a move. In the early 1980s, when the fastest processor had a 10
MHz clock speed, efficient searching was a key to success. “There’s no trick to
solving chess with brute-force searching if you’re in a domain that’s
constrained enough,” Palay says. “If I can out-search everyone, I win. But life
isn’t that simple. That’s why I found B* much more interesting.”
Palay talked to Berliner about his friend Carl Ebeling,
who was looking for a thesis project that involved hardware. Using the
then-novel technology of very-large-scale integrated, or VLSI, circuits,
Ebeling custom-designed a processor to generate chess moves. The resulting
machine, named Hitech, used 64 of these processors—one for each square of the
chessboard—operating in parallel; a master control program polled the
processors and decided strategies. People inside and outside CMU’s CS
department took turns at a third-floor lab in Wean Hall, wire-wrapping
connections. “There was such an enthusiasm for Hitech that I’ve never seen
before,” Berliner says. “Everyone wanted to know what the latest developments
were, and if they could help.”
A working prototype was completed in 1984. Although
Hitech searched smarter, it also employed a certain amount of brute force;
Hitech could consider 175,000 positions per second. (A top human player might
look at one or two moves per second.) In October 1985, Hitech won Pittsburgh’s
Gateway Open chess competition, earning the rank of “master.” That year it also
won the ACM tournament for chess programs. By 1987, it was ranked 190 in the
United States and the only computer among the top 1,000 players.
# # #
Campbell was among those working on improving Hitech’s
search algorithms. As smart and flexible as the machine was, he says there was
a growing feeling that it “didn’t have the horsepower” to beat a human
grandmaster.
The field itself was changing. One of the developers of
the Unix operating system, Ken Thompson of Bell Labs, created his own powerful
chess-playing machine that reached master-level status. In 1982, Thompson
published what Schaeffer describes as “an innocuous little paper” that proved
that chess machines improve in direct correlation with the amount of processing
power they have.
After Thompson’s paper, “chess research died,” Schaeffer
says. For many researchers, the race was no longer to create smarter searches,
but faster computers.
Besides working on Hitech, Campbell also was
collaborating with fellow grad students Feng-hsiung Hsu (CS’90) and Thomas
Anantharaman (CS’86,’90) on another chess-playing computer that became known as
ChipTest. Like Hitech, it relied on VLSI technology, but it was much faster—by
1987, the year it won the North American Computer Chess Championship, ChipTest
was searching 500,000 moves per second.
Danny Sleator remembers the rivalry between the Hitech
and ChipTest teams. “The fact that we had two competing chess systems developed
at CMU simultaneously reflects a number of important things about the culture
in the Computer Science Department,” Sleator says. “For one thing, there is a
tremendous amount of respect for the work of graduate students. The faculty
gives them the benefit of the doubt, and in many cases, including this one, it
pays off. The place is also big enough and tolerant enough that more than one
group can work on the same problem using different approaches.”
In the early days, “there was some good
cross-pollination” between the rival groups, says Campbell, but the
relationship deteriorated. “There was some tension that never got resolved, and
there were some hard feelings in terms of the competition between the two
groups,” he says. ChipTest evolved into Deep Thought, which won the World
Computer Chess Championship in 1989. IBM hired Hsu, Campbell and Anantharaman;
Hsu and Campbell led development on the machine that became Deep Blue and beat
Kasparov in 1997.
# # #
Deep Blue was massively parallel, including 480
special-purpose chips designed to evaluate chess moves. It also demonstrated
conclusively that brute-force computing power could crack tough problems. “My
greatest regret, to this day, is that Deep Blue wasn’t really a ‘learning’
system,” Campbell says. Teaching a machine to play chess the way that humans
learn still hasn’t happened, he says. “You can take an existing program and
‘tweak’ it using machine-learning techniques to play better, but to teach it to
play from next to nothing—how people learn—is still beyond reach,” Campbell
says. “I think that’s a fascinating thing.”
Kasparov claimed to have seen “human intelligence” behind
Deep Blue’s moves—a statement some interpreted as an allegation that IBM
cheated, and which the Deep Blue team said was not true. Berliner says it would
be a mistake to assume that a system based on the statistical analysis of
massive data sets isn’t a form of intelligence. “Intelligence emerges just like
life emerges,” he says. “You take a bunch of inert chemicals which can
replicate themselves, and they form into a creature. It’s the same thing with
intelligence. We can talk about something being ‘intelligent’ when it meets
some certain criteria, but certainly even the dumbest living thing has some
sort of intelligence, or it wouldn’t stay alive.” In that respect, Berliner
says, Kasparov certainly saw intelligence in Deep Blue—but machine
intelligence, not human intelligence.
Berliner also sees intelligence in Deep Blue’s
descendant, IBM’s “Jeopardy!”-playing machine, Watson, which he calls “quite
marvelous.” Just as notable as Watson’s ability to answer “Jeopardy!” questions
is its understanding of slang and idiom, Berliner says. “I’ve worked in that
area of general intelligence, and it’s not easy,” he says.
But Berliner being Berliner, he doesn’t hesitate to point
out where Watson had an unfair advantage over its human competitors. Watson
received the Jeopardy! answers in written form and could immediately get to
work, while the human players were still listening to and parsing the text.
“The computer was way, way ahead in understanding the question—maybe a second
or two ahead—so 90 percent of the time, it rang in before the human,” Berliner
says. “That gives it a tremendous advantage. It was very, very smart to get the
answers, but many of the human beings never got a chance to show what they
knew.”
# # #
Berliner’s willingness to question conventional wisdom
and preconceived notions—including his own—has led to no small amount of
controversy over the years. “I have very high standards for myself,” he says.
“In the end, the only things we have to offer the world are those standards.”
When Berliner decided the work of Russian computer
scientist and chess grandmaster Mikhail Botvinnik didn’t maintain high standards,
he pulled no punches. After concluding that Botvinnik’s published results
couldn’t be duplicated, he accused the venerable old champion of fraud.
Botvinnik’s fans attacked Berliner, but Schaeffer and others reviewed
Berliner’s evidence and concluded that Botvinnik indeed massaged his published
results to achieve his outcomes. Berliner’s 1999 book “The System: A World
Champion’s Approach to Chess” attracted sharp criticism from a few professional
reviewers, but the sometimes very personal attacks left Berliner unbowed.
“A lot of people saw the significant value in what he
did,” says Campbell, who points out that in both the Botvinnik case and the
strategy book, Berliner refused to take an easier path just to avoid
unpleasantness. “There’s a lot to be said for that. It can be lonely, and it
takes a strong personality to be able to do that, and he has that kind of
personality.”
His former students say Berliner’s reputation as a
fearless advocate has overshadowed his generous spirit. “Working with Hans was
a lot of fun,” Palay says. “There was a great deal of graciousness, both on a
personal level and a professional level. He was very much concerned with making
sure that he was treating me well, not just as his student, but as a person.” Palay
says he consciously mimics Berliner’s style when interacting with his own
colleagues.
“You can’t become a top-rated chess player like Hans
without being competitive and self-confident, but I never saw him as being
‘over the top,’” Ebeling says. “He led by example more than anything else.
There was a constant attention to detail, and he was always thinking, looking
out for the next idea that might work.”
Berliner’s research legacy “might not at all be guessable
at this point,” says Palay, though he notes the pendulum seems to be swinging
back from purely statistical machine-learning methods in translation and other
fields to hybrids that include rule-based search techniques. “Some of the
things that he was working on will resurrect themselves over time, as we start
hitting walls,” Palay says. “Tracing them back to Hans will be difficult, but
the seeds will be there.”
As computer scientists try to reduce power consumption
and face difficulty adapting some problems to parallel computing, they’ll look
for more efficient search algorithms, Schaeffer predicts—and they’ll find that
Hans Berliner got there first. “We may find that maybe we don’t need all of
this massive computing power, maybe you don’t need this sledgehammer of
brute-force computing,” he says, but adds that Berliner’s most lasting legacy
is his graduate students. “He didn’t have many, but they were of very high
quality.”
These days, Berliner is out of the fray. He doesn’t play
chess—“once you get to a certain level, you don’t enjoy playing chess any
more,” he says—but he does work on his solitaire game, and keeps records of
winning strategies. When the weather’s good, Berliner finds peace strolling the
beach and thinking.
Before retiring from CMU in 1998, Berliner says he saw a
“deplorable trend” among some students of attempting to talk their way around
difficult problems instead of performing the necessary research. His advice to
today’s students? “Learn all the substantive knowledge that you can,” Berliner
says. “In the final analysis, all knowledge hangs together, and the more you
know, the easier it will be to make good decisions in the future.
“Learn something that has value—something quantitative,
hopefully. Have something you can do that someone else will want to pay you
for—a product. If you don’t have that, it’s going to be tough for you.”
# # # #
Author:
Jason Togyer
jt3y@cs.cmu.edu
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