Recently, I have been finding a paradox at the heart of all that is in life and the world. And so it was with Marina Abramovic’s 512 Hours , a long-duration performance at the Serpentine Gallery in London involving the artist, a dozen or so black-clad assistants, some props, and all 160 gallery visitors. On one hand 512 Hours seemed ridiculous and banal, and on the other, quite extraordinary.

In leafy Kensington Gardens, at precisely 10 am Abramovic swung open the double doors of the Serpentine and welcomed the assembled throng with a broad smile, as if into her own home. At least she was clothed. (In Imponderabilia, 1977, visitors had to squeeze between the naked bodies of Abramovic and her long-term collaborator Ulay to enter a Bologna gallery.) Here she looked demure, in white shirt, black trousers and shoes. Her long black hair swept into a ponytail off a white, remarkably un-aged face.

The self-styled “grandmother” of performance art was born in Belgrade, Yugoslavia, in 1946. There she had what she describes as her “one good idea” (a good artist will have one in his or her lifetime, a genius may have two): to use her body as her material.

In an early work, she scratched out the five-point communist star on her belly with a razor. She screamed until she lost her voice, danced until she collapsed, took psychoactive drugs, lived with Aborigines in the Australian desert for a year in temperatures that never dipped below 45°C. Her work pushed at all limits: of pain, physical and mental endurance, of what is art, of the relationship between artist and audience.

Later years have seen a mellowing, a movement towards long-duration performance and mass audience participation. More than half-a-million people saw Abramovic’s 2010 retrospective The Artist is Present at MoMA New York, 1,400 of them took part in “mutual gazing”, sitting across from her at a table and staring into her eyes. This show brought her a rockstar status (not to mention rockstar friends), shifting her and her medium into the “cultural superhighway”.

There is a locker room where everything has to be deposited. No sunglasses, no watches, and certainly no telephones or cameras are allowed into the performance. “It’s very important that the visitor will not be connected to any other reality,” explained Hans Ulrich Obrist, the Serpentine’s co-director of exhibitions and programmes. Ear defenders are handed out to those who want them. I don mine and enter.

People are randomly arrayed across a low, wooden platform, standing alone or in pairs, and they are sitting quietly on chairs surrounding the platform. Others are leaning against the white walls of the gallery, observing the strange tableau. This is what happens: Abramovic or an assistant leads a visitor by the hand to a platform or chair, instructs her to keep her eyes closed, to breathe, and they stand together for some time, like statues, holding hands. Then the assistant leaves to draw another person into the picture. How do you get picked? I wonder. It’s like waiting to be chosen for a school team without being sure that you like the sport.

In the second room, the sport is slow-motion walking and I immediately like it more. Seven people are taking tiny steps at the slowest pace they can. Abramovic is holding the hand of a slim older woman in a floral dress taking small and purposeful steps, her eyes lowered, shoulders rounded. They walk perhaps seven lengths of the room together.

An assistant with a pixie haircut (in fact, Lynsey Peisinger, Abramovic’s key collaborator) is unexpectedly at my shoulder. She smiles and leads me to the end of the room to start our walk. It is an extraordinary experience. I notice the warmth of her small hand and the comfort of the contact. I am alone but not alone. I have an acute awareness of my surroundings — of the dark green terrazzo tiles on which I am placing my feet, the leopard print onesie five paces ahead of me. I am absolutely present and the slow walking seems to expand each moment, time itself, in a profound way. This is meditation.

In a third room, heads are bunched over 23 school desks in three long rows. On each is a pile of puy lentils and rice, a sheet of A4 paper and a sharpened pencil. Some people have separated their rice and lentils into large piles, others have arranged them in linear patterns. An assistant whispers, “Count the grains of rice.” Surprised (could there be anything more banal?), I ask if this is the task everyone has been given, and she nods. But actually I can hardly get over the marbled beauty of the blue-green lentils; the humble staple has somehow been imbued with a grandeur that brings to mind Blake’s famous line: “To see a world in a grain of sand…”

In 512 Hours the audience becomes the material of a performance that shows them what can happen when they enter fully into the present moment. And the overwhelming response has been gratitude. The exhibition’s Tumblr page abounds in this kind of comment: “Beautiful... I feel thankful for the experience and time to wander through thoughts, memory, silence and stillness.” There is the odd dissenting voice: “This is a complete farce. Art as a great deception.” And some who don’t know what to think, “I don’t know if I loved it or hated it.”

On balance, the experience was more profound than banal or ridiculous — it was probably the most fully present I have ever been in an art gallery. But perhaps the greater paradox was this: the performance was billed as Abramovic’s most radical yet, but it was about sharing with the public a form of a practice — mindfulness, meditation — that is 2,500 years old. A spiritual practice (also radical in its day) first documented in India in the time of the Buddha and the Upanishads.

(512 Hours runs at Serpentine Gallery, London till Monday.)

Charty Dugdalewrites on travel and art

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