Were every celebrity residence in Manhattan marked with a blue plaque, the weight of extra metal would likely send skyscrapers crashing down through the East Coast seaboard, flattening the honeycomb of subway lines that sprawl underneath with the resonant impact of so many names, dates, achievements and moments in time that changed the world. And yet it feels wrong to be standing on the corner of West 18th Street and Sixth Avenue – 101-105 West 18th Street where John Cage and his partner, the dancer and choreographer Merce Cunningham, occupied the entire top-floor loft space of a building that once housed the B Altman and Company department store – and for there to be no lingering imprint left of two remarkable men and the lives they lived there.

I peer through the handsome double-breasted front door. A face glares back. Cellphone encased in sweaty palm, pink corporate shirt, tie bunched at one side, like an extra from The Bonfire of the Vanities; a dude making a deal. I wonder if he grasps the cultural importance of the building in which he stands? If he might understand why a UK-based music writer would choose to fly three-and-a-half thousand miles simply to stand in this spot? To listen, observe, experience those same sounds that Cage heard out of his window and then talked up in elevated terms that most people use to describe music: ‘If you listen to Mozart and Beethoven, it’s always the same,’ he claimed. ‘But if you listen to the traffic here on Sixth Avenue, it’s always different.’

This year, 2012, is the centenary of Cage’s birth. But, in the authentic Cageian spirit, I should have been bold enough to generate a magic random number to celebrate instead. Happy 99th and three months, or 103rd birthday, John! When Cage and Cunningham moved into their lower Manhattan loft in 1978, Cage was standing at a creative crossroads. He was 66 and Sonatas and Interludes, Concert for Piano and Orchestra, Fontana Mix and 4'33" – pieces which had frogmarched everything ‘classical’ music stood for in the opposite direction, over a cliff edge basically, were now decades old. They had status. They were avant-garde ‘classics’, an unsettling paradox which left Cage with profoundly ambivalent feelings. The trajectory between Sonatas and Interludes and 4'33" traces his aesthetic journey in microcosm. Sonatas and Interludes, completed in 1948, made good on the founding keyboard experiments of Henry Cowell. By carefully positioning screws, nuts and erasers et al into the inside of a grand piano, his ‘prepared piano’ was a percussion instrument of make-believe. But Cage’s rhythmic and melodic motifs still sounded like ‘music’.

Concert for Piano and Orchestra and Fontana Mix (both 1958) were by a different Cage. When, in 1951, the composer Christian Wolff gave him a copy of the I Ching, the ancient Chinese ‘Book of Changes’, Cage’s interest in chance procedures stepped up a gear. Concert is notated on 63 loose-leaf pages. Players can start anywhere, but – most radically – the spacing of notes on the stave is your guide about where to place sounds in time. Kiss adios to the narrative tension and release of directional harmony, shepherded by the interpretative goals of a conductor. And for all the soul-gazing provoked by his so-called ‘silent’ 4'33" (1952), that piece is simplicity itself. Cage offers listeners a performance situation analogous to ‘music’, but has stripped away all the apparatus of music.

And why? He would spend the rest of his life answering that question. But by placing environmental sound within a metaphorical frame, Cage was encouraging us to re-evaluate our assumptions about where music stops, or starts, and where sound starts, or stops. Anyone who still reckons 4'33" is about silence can leave the room now.

In his book A Year from Monday (1967), Cage twisted the thumbscrews ever harder. ‘I am less and less interested in music,’ he wrote, ‘[because] I find environmental sounds and noises more aesthetically useful than the sounds produced by the world’s musical cultures’; moreover, ‘A composer is simply someone who tells other people what to do. I find this an unattractive way of getting things done.’ During the 1970s, Cage flirted with the thoughts of Chairman Mao, while his belief in electronics representing the ultimate symbol of musical progress unravelled in proportion with his rising concern about the state of the planet.

Pieces with titles like Lecture on the Weather (1975, for the triumphantly impractical combination of ‘12 speaker vocalists, preferably American men who have become Canadian citizens’) and Litany for the Whale (1980, ‘vocalise for two vocalists’) began to appear; and by 1978, when he moved to West 18th Street, the case could be made that Cage’s philosophical stance had become self-indulgent, muddled and unworkable.

For a composer who had purportedly lost the music bug, Cage was composing a lot of music. If the modality of Litany for the Whale feels slightly vanilla, a sequence of works all invoking the word ‘etude’ could momentarily, if you didn’t know the full context, be mistaken for an adjunct to post-Darmstadt Euro-Modernism. Etudes Australes (solo piano, 1974-75), Freeman Etudes (solo violin, 1977-80) and Etudes Boreales (cello with optional piano, 1978-80) were by a country mile the most technically taxing music Cage had written. Notes everywhere – talk about telling people what to do! But Cage dragged what he termed ‘the writing of difficult music’ into his aesthetic purview by reasoning that, in the current ‘hopeless’ world system, ‘impossible music…[might] induce somebody who had been impressed by this performance to change the world’.

Standing there on Cage’s street corner, I look up five floors to his one-time apartment and wonder what the heck was going on in his mind. When it comes to social and environmental change, violins and cellos and pianos are blunt tools. Why did he insist on framing his critique of society with music? If he believed his statements had real weight, why not do something else altogether? I try to forget I’m a sonic tourist and let the sound of Cage’s corner of Manhattan soak into my being. New York is the best-sounding city on the planet. Bucolic wilderness? Getting away from it all? Count me out of that. Stick your country walks! But I’ll hike New York sidewalks endlessly. I like the ghosts – the reassurance that generations of minds have worked out what goes where, carving up the available space so that people can live, work, create, exchange ideas. Sonically, the city is underscored by this basso profondo of jangling-people energy: voices, car horns, police whistles, the rattle of the subway, the smells, the sirens, refracted light bending around skyscrapers deliberately placed on the New York grid, all coming together to orchestrate this magnificent human music.

When Cage praised the sounds outside his window – once he mused that ‘traffic noise gets louder and quieter, higher and lower, longer and shorter. And I’m completely satisfied with that’ – did he mean it literally, or were we being invited to think laterally? When George Gershwin and Leonard Bernstein needed to implant images of New York City into listeners’ minds, they drew on the associations of jazz. Flip forward a few decades and Steve Reich’s City Life constructed a sonic allegory for New York by embedding sampled recordings of the city’s ambience inside instrumental commentaries. We can be absolutely certain that Cage, had he thought about it at all, would have considered Bernstein’s and Gershwin’s New York to be hopelessly romanticised, and my guess is he’d have wondered why Reich bothered polluting his beautiful field recordings with ‘music’.

Jazz is a metaphor in West Side Story; in City Life, sound becomes dramatised. Cage was interested in neither. ‘I love sounds just as they are,’ he said. ‘I have no need for them to be anything more. I don’t want them to be psychological, I don’t want a sound to pretend to be a bucket, or that it’s President, or that it is in love with another sound. I just want it to be a sound.’

Look at the sequence of eight photographs at the top of this page. I snapped them with my iPhone on April 10, 2012, as a visual representation of how the Cageian spirit works – a photographic mock-up. Cage’s apartment runs along the top; his front door is to the far left of the picture, just beyond where that stony coloured shop awning juts out. Standing on the opposite corner, I decided to take a sequence of 14 photographs – one for every year Cage lived at the address – over four minutes and 33 seconds, and divide the time up accordingly. Gramophone’s editor, Martin Cullingford, then told me that eight photographs would be the optimum number, and so I let one of my cats, Willow, make an editorial decision. I put prints of all 14 images on the floor. You’re looking at the first eight she sniffed. So far, so random.

I believe Cage would have approved. By deciding to apply a sequence of calculations – part arbitrary, part symbolic – to my chosen material (an image of his apartment), and because of Willow’s randomised sniffs, narrative continuity is destroyed. Cage’s harmony works like that too. In Rozart Mix (1965), HPSCHD (1967-69) and Apartment House 1776 (1976), chance procedures dice, chop and reshuffle tonal source material so that you hear the ‘sound’ of tonal music, but without the connecting tissue. Chords we hear instinctively as needing to lean on others are robbed of their function. Cadence points have no meaning. Musical punctuation scatters. Questions are posed like why would a writer choose to end a paragraph in a magazine article with a semi-colon;

Cage’s notoriously mulish stance against Beethoven and jazz/improvised music was grounded in that same attitude. In Beethoven and jazz, the harmony is lined up so that, as he once put it, the sounds ‘talk to each other’; and the problem with sounds talking is that they tell stories which, however profound, detract from the fabric of the sound itself. And arguably my sequence of photographs says more about four minutes and 33 seconds in the life of Cage’s building than rolling footage could, when the medium of film itself becomes the story. Where would this imaginary film begin – where’s its middle, when will it end? Would there be clues about when it was shot? Flared pants might suggest 1978, but the man walking the opposite way is talking on his mobile. Still we’ve learnt nothing about Cage’s building.

But my eight snapshots locate the building in time by making us aware of the activity around it. A single taxi passes by; or the building is temporarily shrouded behind a richly harmonised chorus of vehicles. And then random procedures deal up a wider truth. In film, as in harmony, nothing happening is a problem. Art is useless when it comes to expressing nothing. In life, though, nothing happens with great urgency. One photograph allows this fact to be, as my shutter comes down just as nothing passes by the building. As Cage once said: ‘Which is more musical, a truck passing by a factory or a truck passing by a music school?’ A friend tells me that Cage walked most days to buy provisions from the food market on Union Square at 14th Street. Following in his footsteps, I think about how deeply New York formed Cage. Perhaps his decision to structure his ideas as music was ultimately a disappointing cop-out, belying the fact that, at one level, Cage was more of a composer than he was prepared to admit. There are those who argue that his legacy has left a certain type of composer tied in knots: composers like Michael Pisaro, Radu Malfatti and Jürg Frey whose work riffs off silence and who, the argument goes, prioritise theory and system over music as a social, interactive activity.

And that tired critical cliché doggedly persists: Cage’s ideas are more important than his music apparently, when all pointers suggest the exact opposite is true. Anyone who can make statements complaining about composers ‘telling people what to do’ while thinking, however briefly, that Mao represented liberation and beauty might not be an ideas man to trust. The British composer/improviser Cornelius Cardew’s descent into Maoism represented the end of the road for his life as thinking, creative musician as he turned political activist. But Cage’s belief in the dignity and intrinsic worth of sound rescued him from the same fate: he’d never have allowed politics to interfere with this basic credo – sound for Cage was everything, and he indulged New York and the city indulged him.

I arrive at Union Square and laugh. Alongside music and Marcel Duchamp, mushrooms vied for Cage’s affection because, he said, music and Marcel Duchamp and mushrooms all begin with the letter ‘M’. Randomly, the first thing I see is a mushroom stall and I think, wow, New York sure sounds like John Cage.

Listening to the sounds around Cage's appartment

I made these two field recordings on April 10th 2012 outside John Cage and Merce Cunningham's former apartment on the corner of West 18th Street and 6th Avenue in midtown Manhattan. They take inspiration from different elements of different Cage works in order to engage with and explore some of his ideas.

The first recording was made mid-morning, the second during the early evening after I'd walked with the composer and improviser Jessica Pavone to the food market in Union Square on 14th Street, where Cage shopped every day, and where the first stall we saw happened to be selling mushrooms.

Deciding on a duration of 4 minutes and 33 seconds (although one recording tipped the dial into 4 minutes and 34 seconds), I stood outside Cage's front door looking at a score of one of his late-period number pieces. Notes sit on disembodied staves. Time brackets above indicate a starting point and end point during which the note can be sounded. I used those durations to tell me how far to walk before changing direction and walking the other way.

Cage teaches us to be accepting of what happens, that randomness can be symbolically accurate and precise. That said, I didn't expect a vast utility truck to pass just I started the second recording; and if you listen carefully you can hear the steady plod of my feet imposing a rational pulse on the otherwise randomly captured soundscape.