"If you tell your leg to stop hurting," says the Venerable Monk, "does it listen to you?" We're not meant to look at him when he's speaking. We have to focus on our sitting, because he's walking around with the incense board in his hand. The incense board is like a flat whacking-stick, to be used if any of us nods off during meditation. When it's swung against someone's back, it makes a noise that jolts the rest upright.

"The triangle is the most stable shape in trigonometry," the Venerable explains, "so that's why we sit in full-lotus." The full-lotus position is sitting cross-legged, with your left foot on your right thigh and your right foot on your left thigh. It locks you in, so you can focus on training your mind while sitting in the semi-dark facing a blank wall in the Buddhist Meditation Centre.

Chan Buddhism, which the Japanese call Zen, was introduced to China from India by a monk named Boddhidharma. It is said that Boddhidharma sat in a cave for nine years before he attained enlightenment. They say he sat so still for so long that his shadow became permanently etched on the wall.

When we enter the meditation hall, we must leave all our distractions outside. The monk passes around a basket for us to deliver over our final attachment to the outside world. Everyone looks anxiously at the stack of mobile phones as they drop theirs in, but no one says a word, because this is a five-day silent retreat. There is also to be no reading or writing, or tactile contact with anyone.

According to the most recent census, Buddhism is the fastest growing religion in Australia. We have the earthly signifiers to prove it - the biggest Buddhist temple in the southern hemisphere is the Nan Tien, or ‘Paradise of the South', Fo Guang Shan temple, near Port Kembla. There are massive stupas in unassuming suburbs, as well as small temples and meditation centres dotted all over the land, for different denominations: Mahayanan, Theravadan, Tibetan, Sri Lankan, Pure Land, Thai forest tradition, Zen or Chan. But it's the heart of the practice, not these buildings, that matters, all the Venerables say. During my first retreat, a friend who almost became a monk explained Chan Buddhism to me: "It's like having a single flower in an empty room. Some people don't see the point of the empty room, but it's the empty room that brings out the beauty of the flower."

Quite a few Buddhist centres conduct retreats. It is here that people learn fast that the festively plump Buddha in their backyard water feature may be rollicking in fits of laughter, but the actual practice is very painful. If it isn't, then we're taking short cuts. No pain, no gain. Even without any distractions, I find I can't sit still for half an hour without suffering. The side of my ear itches. Unexpected spasms shoot through my leg. The backside is more complicated than I'd appreciated: every time there is a clenching ache, I discover a new muscle. Out of the corner of my eye I notice 65-year-old Irene, who has sat still for an hour, unperturbed by my restless shifting.

I also discover how quickly feelings of loving kindness cultivated in the last half-hour dissipate when the person next to me releases gas. Because we are not supposed to move, all our attention is focused inwards - and we start to magnify all our small irritations. What a torment the mind is.

Mine starts thinking about mobile phones a lot, because I have just relinquished mine, and also because it used to be my job to sell them. In the silence, I realise that I was a speech peddler - that when I sold a phone, I was helping people to discharge their verbal effluent at the cheapest cost. In the past, only schizophrenics or sages heard a thousand voices in their heads. Now, anyone who doesn't hear these voices is seen to be cutting themselves off from society. A person's phone is like a lively child they can show off to others: Look! Mine can sing, vibrate to a tune, show faces, play games and remember important events. But after the sound-and-light show, it is dumped in the bottom of a handbag clotted with congealed lollies and used bus tickets. It is suddenly bewildering to me how a whole living person can be compacted to this small plastic rectangle. I marvel that we don't have more reverence for the device, because it would have been a miracle to a person living two centuries ago. The quiet also reminds me that there used to be a time when people saved their speech for certain times, a time when words had more weight.

After a few days, I begin to do things without so much witless white-noise commentary in my mind. Our head, hands, ears and eyes are kept busy in other ways. The gong wakes us up at 4.30 in the morning, while it is still dark, to do yoga exercises so our muscles don't cramp up. Between silent sittings, we sweep and mop and clean. We eat our meals in silence, so we can reflect on all the efforts of the thousands of sentient beings it took for a single grain of rice to reach our bowls: from the first person, who planted the rice seeds, to the last, who scooped it into the dish.

After eating, we rinse our bowls with hot water and drink up the residue, so nothing is wasted. We wash up. The Venerable then fills each of our bowls almost to the brim with water, and directs us to walk around the great perimeter of the centre without spilling a single drop. It takes me three attempts to understand how much effort it takes to be careful. Then we go back to our sitting.

My fellow retreat-goers are not people with lots of time on their hands. They are Chinese parents and professionals and other full-time workers who have saved up their annual leave to do this. In theory, it's about being present in all our thoughts and actions. In practice, it's about learning to sleep through the night when a stranger in the bunk below is snoring heavily from a cold. It's about quietening your mind down enough that you are no longer affected by severe, irrational annoyance, and about recognising that a noise is just a noise. And if sleeping through the night is impossible, then it's about not whingeing in the morning.

When the retreat ends, we are allowed to talk again and our mobile phones are handed back. There is a world outside to catch up with, because we've slowed down so much. Some people switch their phones back on when they get into their cars. Others put theirs back in their bags and still don't speak. We've only just begun to realise what silly, monomaniacal obsessions we think and talk about each day, so we make resolutions to listen. We leave the Chan hall and the door closes, with its sign intact: Noble Silence Please.