The particular ritual of the concert brings a kind of order to living. Concert days culminate in a seventy- or eighty-minute period of time that begins at 8:05, or 8:13 (late ticket buyers still in line).

Of course, at Wigmore Hall, this "8 o'clock" is 7:30 (often 7:33), in Rome it's 9. Unlike the painter or the poet (one more revision?), the performer of live entertainments is on the spot/in the hot seat/in the limelight -- and then it's over.

Irretrievable. Done. One way or the other, gone to memory, or preserved "for posterity" in a "live recording." But not really. Really, it's not preserved, it's not saved -- we can't be saved. It's gone. Whatever it may have meant or signified, no matter how much it cost in dollars or sweat or blood -- it's over, gone, finito.

Until eight o'clock comes around again tomorrow...

A celebrated American violin pedagogue sent her young virtuosos to listen to five or six recordings of a new piece. The kids calculated the speed of each performance with a metronome, averaging the numbers together to determine the right tempo for their own performance -- a focus group for tempo!

Other teachers counsel strict avoidance of recordings. Is it better to read for ourselves? Erich Leinsdorf faulted young conductors who learned new repertory from recordings. Obvious sonic details (the triangle!) were prominent in their sense of a piece, but not basic structures or concepts, Leinsdorf maintained.

Embarking on research in science or the humanities, an initial stage is the discovery and reading of all the previous work. Lawyers study case law, as well as statutes. As he prepared to record Beethoven's "Hammerklavier," I discussed this with Russell Sherman. Would it make sense to find and listen to all the previous recordings of the sonata? Or can a pianist, in our period of relatively easy access to the legacy of recorded performing, dare not to listen to previous recordings of "his" piece? Can these recordings simply help in making sure there are not errors of text-reading? Or will they impede music making?

Perhaps listeners know the legacy. Jerome Lowenthal told me he was accosted backstage after playing Tchaikovsky's First Concerto. A woman asked: "Do you play the Rubinstein or the Horowitz version?" Arturo Toscanini is reported to have said he couldn't compose because his head was too full of other people's compositions.

Is there middle ground? Is there some way to be aware of the recorded past, to draw information about style from it -- even inspiration and courage -- and yet not become a jukebox or encyclopedia?

In classical music, there are those who believe that thinking about music can compromise feeling -- compromise our emotional response to music. Alfred Brendel's example vividly shows us that such notions are foolish. Mr. Brendel scrutinizes the canonic texts of the piano repertory. He examines the behaviors of piano playing and musical life, and he's shown that deep reflection can yield (not impede) a heightened emotional and even spiritual connection to the muses.

To a young pianist, it was a powerful example. From the high balcony at Carnegie Hall, I overheard Mr. Brendel grapple with Beethoven's music. I recall the thrill of anticipation I felt just buying the tickets for one of his Beethoven cycles. And then:

I had been, let us say, to hear
(From highest Carnegie incline)
The latest Fōld of the great garment of Beethoven's sonatas
Transmitted by Mr. Brendel through his hair and fingertips ...

(And for that, apologies to Mr. Brendel and to T. S. Eliot.)

From that high place -- from those cheap seats -- I witnessed probing and unforgettable performances: of Schubert's and Beethoven's music, of Liszt's Sonata, of the Two Saint Francis Legends, of Robert Schuman's C-Major Fantasy. On those occasions, control was "in league with chance," as Mr. Brendel has described an ideal.

Through Mr. Brendel's words, as well, provocative guidance has been offered. There are many well-worn copies of Musical Thoughts and Afterthoughts, and Music Sounded Out. Alfred Brendel has led generations of musicians "away from the piano, and to themselves."

Mr. Brendel has written of "the unseen hand" that can grip an audience and a player. I will paraphrase a passage from his essay, "On Recitals and Programmes":

There has been a spiritual link between Alfred Brendel and his public -- an intense physical experience, unique and unrepeatable, tied to a specific time in history, tied to the sounds of particular halls and instruments, to the sudden bursts of the athlete, and the peregrinations of the poet. All has been well, and Mr. Brendel's mastery has only been surpassed by the grip of an unseen hand, that has kept its hold over a player and his listeners alike for decades -- a few timeless moments... Through a long and magnificent career, he has brought us to an understanding, and a love, that we didn't know ourselves to be capable of.

Mr. Brendel, thank you.

I wasn't a prodigy. I took lessons from the lady down the street. (Her name was Joy Lord.) In high school, I played concertos with several Iowa orchestras. In a big city, I wouldn't have had the opportunity. I wasn't playing all of Chopin's etudes. Nothing like that. Being there gave me a chance, to dream bigger than I was.

What is musical talent? It is an ability to hear and coordinate, certainly. But also it is a capacity to experience. Talent can be a means to dream, unafraid.

We need adolescents(ce) to show us the future.

When I give the first performance of new music (I'm playing a new piano piece by Nico Muhly in May), my performance functions to begin staking out an identity for that music in public. Actors are said to "create" new roles. Immediately things begin to shift as my playing is heard, as I play again, or record. Nothing ever gets taken back.

With canonic music, no matter how significant we believe our insights or approach to be, we don't make much of a difference. The music is large -- like a person who has lived a long time and for whom a few minutes represent only a small, small fraction of a life. In contrast, a few more minutes in a child's life significantly increase the whole.

Scripted music does continue to change, as it's played. Its identity is recentered, at an increasingly slow rate. How radically we depart from what has been done before in performing may be part of how far this recentering goes.

Does this explain Mannerism? As a style, or a particular piece of art becomes more and more familiar, an artist's assertion of personal voice (an attempt to recenter the piece, or school) may result in extremes. It is not exactly a wish to shock that drives Beethoven or Parmigianino -- but the desire to be heard.

It's dangerous. And not because we don't want superlative music. Artistic experience isn't one-size-fits-all. What plays well in Los Angeles reads differently in Paris, or Dubai. We know music is changing. Well, music itself is change!

Celebrity can sell. Orchestras bank on it -- Beethoven: The Complete Symphonies. But we know every single performance by Mr. Pollini is not better than every performance by Mr. Ponthus. And we should know that every scrap of paper touched by Beethoven's hand does not encode music that is "superior" to every note penned by Muzio Clementi.

The greatest risk is in the making of music itself. If, as we play, we judge everything we do, and respond harshly to "mistakes," or momentary lapses of taste, technique, or style, we may be so disappointed that we cannot be our "best." In order to be really present in the moment, a certain suspension of judgment serves better. Not about the facts particularly. "Is it quiet, or quick, or connected in sound?" Fine. But when it comes to drawing conclusions, it's better to wait, just to keep going where the lines and harmonies take us. Just to surrender at least some of our control, to the sound we perceive, to the breathing of the audience, to what Mr. Brendel called the "unseen hand."

In other music, high registers are thin. Earlier instruments and techniques may corroborate this thinness: no steel "E" strings on eighteenth-century violins, singing voices differently "supported." Eighteenth-century pianos and harpsichords are paler higher up; high notes sustain less well than notes in their lower registers. High notes are up there -- where God is? Where Heaven is? A place a human might aspire to, but not confidently occupy. In a lot of older European music, gestures that rise into high registers don't just go up -- they "ascend."

Last year, I played Messiaen's "Quartet for the End of Time" with several different groups of excellent musicians. As the cast of players changed around me, the music changed too.

The final movement, the slowly unfolding "Louange à l'Immortalité de Jésus" ("Praise to the Immortality of Jesus"), is a poem for violin and piano. It goes up very high on the fiddle. It's hard to play. It's hard to ascend ...

In a performance in Boston in Jordan Hall with James Buswell, I became overwhelmed. Was it the intensity of playing this very emotional music in a big room for a thousand people, built up through the whole hour-long piece? Was it Buswell's magnificent mastery? The physical sound of the sustained line rising higher and higher above the impossibly slow heartbeats (bum-baaaa, bum-baaaa) of the piano, repeating, and repeating, and repeating? Was it the recollection that Messiaen heard this music played in the hall decades before? Or thinking of the memorial event for a friend that took place on the same stage the day before our performance?

After we finished playing, after the last thin sounds entirely dissipated, after I rose from my seat, and as we bowed, my eyes filled with tears.

Mr. Buswell is a very accomplished collaborator and complimentary (when due), though not effusive. The next day when I ran into him, he asked a slightly oblique and rather plaintive question:

"Have you been in the chair again?"

I had not.

"We have been, let us say, to hear the latest Pole
Transmit the Preludes, through his hair and fingertips."

Were those the celebrated red locks of Paderewski? Like many Poles playing the piano, he specialized in Chopin. There were so many Chopinists in the early years of the twentieth century -- just as sound recording really got going -- that, although we don't know how the players of the 1840s sounded when they played Chopin's music, we do have a lot of recorded evidence of the playing of the 1920s and 1930s. This forms a (somewhat anachronistic) performance-practice reference-collection for this repertory.

It can be intimidating. Before we play the Nocturne, opus 55, number 2, we might be thinking of Ignaz Friedman's 1936 recording. (And some players imitate it.) There are pianists who avoid the Fourth Ballade because of Josef Hofmann's overwhelming 1938 account.

Several years ago, in my essay "Exorcising Volodya," I described my efforts to remove, from my performances of Chopin's Polonaise-fantaisie, details from Vladimir Horowitz's 1966 recording -- details I imitated even though I didn't like them. Recently, as I have studied the Polonaise-fantaisie again, I've been thankful there are no early twentieth-century recordings of it. We can wonder how Friedman, Hofmann, or Alfred Cortot, may have played the piece. But, either because of technology -- it would have required several recorded "sides," like a concerto -- or perhaps because of this piece's reputation as discursive, none of the old players put it onto shellac.

Our sense of music is colored by when and how it entered the recorded repertoire -- even if we are not specifically aware of the first recordings. Do we have a more "modernist" view of the Polonaise-fantaisie than we might have of Chopin's First Ballade -- because the Polonaise-fantaisie was not recorded until after World War Two?

The music is intricate with a lot of syncopation, and these kids fit it all in, around the clicks. This kind of practicing is not so unusual in college and high school bands. Technology has allowed Maelzel's metronome to roar.

Previously, I've been aware of string quartets that practiced with amplified metronomes, souped-up clickers loud enough to be heard in a full-volume rehearsal. Old metronomes required quieter playing.

I don't believe we know just when musicians started to play whole passages, or whole pieces, with the metronome running. A few, like Arthur Schnabel, lined up the metronome's ticking with off-beats, or inner parts of beats, in the music being played.

In a 1948 essay, Arnold Schoenberg complains of the current style of performing "suppressing all ... unnotated changes of tempo." He writes: "Almost everywhere in Europe music is played in a stiff, inflexible metre -- not in a tempo, i.e. according to a yardstick of freely measured quantities."

Do we turn ourselves into machines: running on a treadmill at the gym, our hands gripping a game-controller, or practicing over and over with a metronome?

As I was speculating about this, I asked another question: "For the purpose of this count, what is a 'concert'?" Of course, evening-length performances with an audience in a theater. What about playing in somebody's living room? What about the performance of a single short piece? Television? Open rehearsals? No wonder I haven't kept track.

There are artists who monitor and record bodily functions, or document the mundane or arcane physical details of life. Ok, I'm keeping a log now. I'll list each time I play the piano, for how long, and for whom...

In the coda, several notes in piano part had been "redistributed" -- scratched out of the music written for the left hand and added to the right-hand part, and vice versa. Some pianists redistribute habitually, to make things easier, or take a note with their right hand if a wide left-hand stretch is unreachable without breaking. There may be questions about how specifically composers intend, or notate, piano music for one hand or the other (or how much we may want to grant them such authority)?

Certain difficulties in Beethoven's piano sonatas cause long discussion: the opening diminished-seventh octaves in Opus 111, the first treacherous left-hand jump in the "Hammerklavier." Jacob Lateiner insists that the notation of passages like the hilarious dive into the lower register in the first movement of Beethoven's Opus 54 (measure 38) shows the composer's awareness and authorial command regarding which hand is to play which notes. (The right-hand notes are all written with stems going up in this passage in Opus 54.)

Some piano composers care. Others may care less. And some pianists redistribute a lot, others resist. Alfred Cortot apparently played Ravel's Left-hand Concerto with two hands! Abbey Simon finds intricate redistributive solutions. Some players will redistribute a C-Major scale.

Before a performance of the "Hammerklavier", Lee Luvisi was struck with fear contemplating Rudolf Serkin's presence in the audience. He says: "In all my previous performances of the sonata I'd played the opening with two hands... I hadn't wanted to make a mess of it at the very beginning. Moments before going onstage I had a fit of conscience. 'My god, Serkin's sitting there, if he sees me play that with two hands, he'll never forgive me. He won't speak to me the rest of my life.' I had never even practiced it with one hand. But, I knew, it had to be all or nothing."

I asked Milton Babbitt about difficult-to-play jumps in register that occur in his piano music. It doesn't matter which hand is used, he said. The continuing question: Is musical notation a set of instructions or a map of what is to be heard? Of course, it's both, in varying and shifting proportions. For Babbitt, it seems it's the result that matters, not the means. (Or, that the result would not be affected by the means.) In other pieces, the route is critical.

In Messiaen's Merle noir, in the coda, the piano part is hard. If all the notes written on the upper staff are played with the right hand and all the lower-staff notes played with the left hand, then there's constant hand-crossing and overlapping. I practiced it. The result is not absolute tonal equality. Some notes protrude, others are subdued. It's a constantly shifting avian chiaroscuro of sound.

Virtuoso pianists spend so much time attending to what's difficult in virtuoso pieces that it can seem these difficulties -- often passages of short, quick notes -- really are the most important thing in a piece of music. Frequently, it's the other way around. Frequently, all those fast notes matter least. It's the long tones that convey "meaning" and emotion. It's with long tones that poignant dissonance is stressed. Long tones are where the important syllables of the important words would fall -- if there were any words ...

Some instrumentalists like to make fun of singers. Singers can't "count," singers have an imprecise command of rhythm, so the jokes go. But the kind of singing (or speaking) in which the long sounds of critical words in a text are strongly produced and held, and the relatively unimportant quicker syllables are not over-pondered, the sort of vocalizing that may even linger when something is disturbing, or hard-to-follow, and then rush ahead with little linking-words on the tongue -- that kind of singing has everything we players of instruments might want. Let's not learn how to count, but how to deliver.

9/8 meter is in three. (There are three beats in each measure.)

9/16 meter is in one.

Since the pervasive use of photography by visual artists, the question arises in art schools: "Do art students need to learn how to draw?"

To the question in Munich, my immediate answer was that pianists in music schools still do study Chopin's etudes, and Liszt's, and Beethoven's sonatas. Whether this is essential to master the instrument, I doubt. It does influence (or skew) a basic sense of what music is. And, that resultant understanding of "music" is inclined to line, goal (teleology), and development.

It used to be that almost every player of the viola started out by learning the violin. For a few decades, this has been changing. Now, there are excellent violists who start their musical lives directly with the viola. Do they sound different?

What kind of music-making would ensue if the repertory pianists studied began with Stockhausen?

Maureen made the video first. She started improvising movements and shooting video, with careful, subtle lighting. The movements are slow and slow changing. Her body makes the shape of a triangle: her back arched, her thighs down flat, one forward, one back, her knees and feet bent up and grasped and ungrasped by her hand behind her back.

The film was made in segments and edited. The angle of the camera shifts very slightly through the finished piece. After the film was nearly complete, Maureen found the music. She fitted Glass's own recording of his Fifth Piano Etude to the images.

Before our first rehearsals together, Maureen gave me the video with Glass's playing as the soundtrack. This is music I have played quite often. I didn't want to copy the details of Philip's playing. I tried to find the points of coincidence between notable details of the movement, and punctuations and cadences in the music.

My goal was to be able to accompany the film (with the sound turned down), making the phrases of music line up or make sense with Maureen's filmed movement -- without exactly mimicking Philip's tempos or rhythmic inflections. It's tricky. Some phrases of the movement patterns go by more quickly. A completely steady, unvaried pace in playing the music is not possible.

Once we got into rehearsals, I played through the music with the video several times, as Maureen drew my attention to details of the movement. "You see my thumb touches the floor there." Or, " My chin disappears behind my arm, on 'four'."

On stage, Maureen performs these same movements live. She can see some of the projected moving image, and she can hear my playing. Often, her live performance virtually matches the film, but never exactly. I feel that a lot of the beauty and overall emotional quality of the work come from this friction -- this failure of the live performing to exactly coincide with the movements seen in the film.

So there are layers:

• There's the video that doesn't change (although it's murkier or easier to see depending on conditions in each theater).

• There's me trying to match my live playing of the music to what I can see in the video.

• And there's Maureen watching and listening, and doing the movements in sequence in real time.

I've done performances with other dancers using "live video" -- real time projection of events taking place in the moment. Some critics and audience members thought my performances with Maureen used live video. Perhaps these observers were mesmerized, and didn't notice the subtle changing of camera vantage point, or slightly asynchronous cadences.

Live video would be easier. I could play more freely. But then, the fragile, elusive links from the "script" -- the pre-made video -- to me, and to Maureen, would not be part of the art.