Sounds Like Bach |
Back when I was young -- when I wrote "Gödel, Escher,
Bach" -- I asked myself the question "Will a computer program ever
write beautiful music?", and then proceeded to speculate as follows:
"There will be no new kinds of beauty turned up for a long time by
computer music-composing programs... To think -- and I have heard this
suggested -- that we might soon be able to command a preprogrammed
mass-produced mail-order twenty-dollar desk-model 'music box' to bring forth
from its sterile circuitry pieces which Chopin or Bach might have written had
they lived longer is a grotesque and shameful misestimation
of the depth of the human spirit." I went on and on in this vein. What do I make of such speculations now, a quarter-century
later? I am not quite sure. I have been grappling for several years now with
these issues, and still there is no clear resolution. In the spring of 1995, I came across the book "Computers
and Musical Style" by David Cope, a professor of music at the University
of California at Santa Cruz, and in its pages I noticed a mazurka supposedly
in the style of Chopin, written by Cope's computer
program EMI (short for "Experiments in Musical Intelligence"). This
intrigued me because, having revered Chopin my
entire life, I felt certain that no one could pull the wool over my eyes in
this department. So I went straight to my piano and sight-read through the
EMI mazurka several times, with mounting confusion and surprise. Though I felt there were a few little glitches here and there, I
was impressed, for the piece seemed to "express" something. Had I
been told it had been written by a human, I would have had no doubts about
its expressiveness. It sounded slightly nostalgic, had a bit of Polish
feeling in it, and it did not seem in any way plagiarized. It was new, it was
unmistakably "Chopin-like" in spirit, and it did not feel
emotionally empty. I was truly shaken. How could emotional music be coming
out of a program that had never heard a note, never lived a moment of life,
never had any emotions whatsoever? The more I grappled with this, the more disturbed I became --
but also fascinated. There was a counterintuitive paradox here, something
that obviously had caught me enormously off guard, and it was not my style to
merely deny it and denounce EMI as "trivial" or
"nonmusical". To do so would have been cowardly and dishonest. I
was going to face this paradox straight on; I was going to grapple with this
strange program that was threatening to upset the apple cart that held many
of my oldest and most deeply cherished beliefs about the sacredness of music,
about music being the ultimate inner sanctum of the human spirit, the last
thing that would tumble in AI's headlong rush towards thought, insight, and
creativity. Had I only read about EMI's architecture and not heard any of
its output, I would have paid little or no attention to it. Although Cope has
put in far more work on EMI than most AI researchers ever do on any one
project, its basic principles simply did not sound radically new to me, or
even all that promising. What made all the difference in the world for me was
carefully listening to EMI's compositions. Over the next few months, I lectured about EMI in many places
around the United States and Canada, and what I found truly surprising was
that hardly anyone in my audiences seemed upset at Cope's
coup in the modeling of artistic creativity; hardly anyone seemed threatened
or worried at all. I, on the other hand, felt that something of the
profundity of the human mind's sublimity was being taken away. It seemed
somehow humiliating, even nightmarish, to me. The deepest underlying principle behind EMI is what Cope terms
"recombinant music" -- the identification of recurrent structures
of various sorts in a composer's output, and the reusing of those structures
in new arrangements, so as to construct a new piece "in the same
style". One can thus imagine feeding in Beethoven's nine symphonies, and
EMI coming out with Beethoven's Tenth. EMI's central modus operandi, given a set of input pieces, is: Lack of space unfortunately prevents me from describing here the
many types of intricate mechanisms by which EMI picks up stylistic
characteristics and carries out the many-leveled "recombination"
that Cope has programmed. In my lectures on EMI, I nearly always let my audience hear a
handful of small two-voice pieces for the audience. The listeners are
forewarned that there is at least one piece by Bach in the group, and at
least one by EMI in the style of Bach, and they should try to figure out
which ones are by whom (or by what). After the pieces have been performed, I
ask the audience to vote. Usually, most of the audience picks the genuine
Bach as genuine, but usually it is only about a 2/3 majority, with roughly
1/3 getting it wrong. And it is not by any means always the less
sophisticated audience members who make the wrong classification. EMI is evolving -- it is a moving target. Cope began work on his
program in 1981, and in all these years he has not let up on it. EMI's early
pieces are, like any fledgling composer's, pretty amateurish affairs, but its
later output sounds increasingly impressive, and Cope has grown more and more
ambitious over time. Whereas initially he was proud of EMI's production of
short two-part inventions and short mazurkas, he now has EMI producing entire
sonatas, concertos, and symphonies. There is even a "Mahler opera"
under way now -- something that would certainly be a challenge for any human
composer to carry off. Style, of course, is a multi-layered phenomenon. There are
shallow and deep aspects of style. It is quite possible that someone could be
capable of capturing many of the shallower trademarks of a composer and yet
miss the bull's-eye as far as essence is concerned.And
so, how much are we being fooled when, on hearing a piece of music, we
respond to some gestures that in the past we have come to associate with
composer X, and then exclaim to ourselves, "This piece sounds like
X"? Can we even distinguish clearly between responses at a shallow level
and a deep level? Indeed, what is the difference, in music, between "shallow"
levels and "deep" levels of style, between "syntax" and
"semantics", between "musical form" and "musical
content"? Is there really any such difference at all? In my lectures, I usually have a second musical interlude, this
time involving mazurkas -- one by Chopin and one by EMI. One time, when I
gave this lecture at the world-famous Eastman School of Music in Rochester,
New York, nearly all the composition and music-theory faculty was fooled by
the EMI mazurka, taking it for genuine Chopin (and the genuine Chopin piece,
by contrast, for a computer-manufactured ditty). An Eastman music student, Kala Pierson, wrote me an email about this event in which
she said, "I voted real-Chopin for the second piece, as did most of my
friends. When you announced that the first was Chopin and the second was EMI,
there was a collective gasp and an aftermath of what I can only describe as
delighted horror. I've never seen so many theorists and composers shocked out
of their smug complacency in one fell swoop [myself included]! It was truly a
thing of beauty." One stunning lesson from my Where will we have gotten in twenty more years of hard work? In
fifty? What will be the state of the art in 2084? Who, if anyone, will still
be able to tell "the right stuff" from rubbish? Who will know, who
will care, who will loudly protest that the last (though tiniest) circle at
the center of the style-target has still not been reached (and may never be
reached)? What will such nitpicky details matter, when new Bach and Chopin
masterpieces applauded by all come gushing out of silicon circuitry at a rate
faster than H2O pours over the edge of Niagara? Will that wondrous
new golden age of music not be "truly a thing of beauty"? Consider "Prokofiev's tenth sonata", as Cope calls it.
In the liner notes to EMI's first compact disk, called "Bach by
Design", Cope wrote, "This computer-composed Prokofiev sonata was
completed in 1989. Its composition was inspired by Prokofiev's own attempt to
compose his tenth piano sonata, an attempt thwarted by his death. As such it
represents another of the many potential uses of programs such as EMI (i.e.,
the completion of unfinished works)." To me, this remark comes close to
blasphemy. What worries me about computer simulations is not the idea that
we ourselves might be machines; I have long been convinced of the truth of
that. What troubles me is the notion that things that touch me at my deepest
core -- pieces of music most of all, which I have always taken as direct
soul-to-soul messages -- might be effectively produced by mechanisms
thousands if not millions of times simpler than the intricate biological
machinery that gives rise to a human soul. This prospect, rendered most vivid
and perhaps even near-seeming by the development of EMI, worries me
enormously, and in my more gloomy moods, I have articulated three causes for
pessimism: That loss would be an inconceivable source of grief to me. In a
sense, the loss just described would not be worse than the loss Although Kala Pierson and many others
may hail its coming as "truly a thing of beauty", the day when
music is finally and irrevocably reduced to syntactic pattern and pattern
alone will be, to my old-fashioned way of looking at things, a very dark day
indeed. |