NARRATOR：

Listen to part of a lecture in a music history class.

MALE PROFESSOR：

So, let's continue our discussion of twentieth-century music.

By the early twentieth century, some composers in Europe and the United States, composers of what's considered classical music, were already moving away from traditional forms and were experimenting with different ways of composing- in many cases, moving away from traditional Western scales and tonalities.

But as the century progressed, some composers, composers of what was called avant-garde music, went further.

Their experiments with musical composition were not always well accepted.

Quite the contrary. You see, many people felt avant-garde music was too radical and wasn't even legitimate art.

A case in point is the composer John Cage.

Cage was probably the most famous composer of twentieth-century avant-garde music.

He didn't begin as a musical radical, but as time went on, his musical experiments led him there.

What caused the change? Two experiences in particular entirely changed how he thought about music.

The first was his 1951 meeting with the avant-garde painter Robert Rauschenberg...

Now, avant-garde is a term that applies to many different artistic genres.

Rauschenberg had created a series of famous paintings that consisted simply of white paint of different textures, on canvas. That's all they were-white.

But the concept of these paintings actually wasn't so simple.

Rauschenberg was asking, in effect, how much could you leave out of an artwork and still have something?

Because in fact, even on a purely white canvas there's still plenty to see-shadows, dust, reflections....

For Cage, Rauschenberg's White Paintings opened up a whole new way of understanding what art could be.

The second key experience in Cage's development came when he stepped into an anechoic chamber.

An anechoic chamber is a room with special walls that absorb sound. Anechoic means without echoes.

So an anechoic chamber is a room where, in theory, you can experience total silence.

But Cage entered this room and he heard two sounds- one high and one low.

The high sound, he was told, was his nervous system operating. And the low sound was his blood circulating.

Cage was profoundly affected-he realized that music doesn't need to be created intentionally-we find it all around us.

This idea came to be called found sound.

It's the sounds that are already there- traffic outside your window or whatever- for Cage they were just as musical as sounds made by musical instruments.

These experiences led Cage to create a composition that would convey the idea of found sound.

That is, it would provide an opportunity for the audience to identify random sounds of the environment as music.

So he composed a piece called 4'33'', commonly known as the silent composition.

And this composition was completely silent. Literally.

When it was performed the first time, a pianist sat on stage at the piano, and the only thing he did was raise and lower the lid of the keyboard to indicate the beginning or ending of a movement.

4'33'' had three movements- but not a note was played in any of them.

Well, the audience was outraged. Music critics called the piece ridiculous. But Cage saw no reason for the outrage.

The fact that the audience was scandalized showed that they missed the whole point of his composition, which was that there's no such thing as silence- no such thing as a complete absence of sound.

There was, in fact, during that first performance, the sound of wind and rain and people muttering.

Cage had a different understanding of silence- he defined silence as the absence of intended sounds.

So to perceive 4'33'' as music, the audience needed to tune into the sounds around them.

This was quite revolutionary, so, we should probably be sympathetic to their reactions at the time... I mean it's confounding people even today.

Cage's silent composition is still performed all over the world. But I'm afraid to say, it's often misinterpreted.

It's been choreographed, in dance performances, for instance, in which case the sound was the beat of the dancers' feet against the stage floor.

And it's been performed by people who made noises on purpose to call attention to the piece's silence.

Can you see why we can consider these performances to be misinterpretations?