Listening to a recent Gardeners' Question Time on the radio I heard a panelist quote the 18th century French writer Voltaire. The state of the world is so frightening, said the panelist, so utterly dreadful, that one should concentrate on 'cultivating one's garden'. The words come from Voltaire's novel Candide. The hero is an innocent abroad, who finds the world too unpleasant and complicated to handle. Cultivating one's garden becomes a retreat to what is controllable, comfortable and safe. This was, of course, before artificial pesticides and fertilizers made gardening an eco-political issue.

Voltaire himself was a brave but contradictory hornet of a man -- the last person to want to retreat to his garden. He spent his working life campaigning for social justice and tolerance, attacking the corruption of royalty and the Church, and eventually making a fortune for himself. He prepared the ground for the French Revolution, which hit the road eleven years after he had died.

In case you are wondering, I am not about to claim that Voltaire was a great lover of the bicycle. It hadn't been invented then, and anyway I suspect he would have preferred a coach and four. I am not even sure that he ever put hand to spade. However, gardening and cycling do have a few things in common: both can involve exercise, a love of nature and a sense of personal control.

The irony is that the very people with the most ordered gardens, with the most meticulously manicured lawns and flower beds, are often the keenest to use the offerings of the chemical companies in their command-and-control operation against insurgent Nature. By convincing the individual that he can control at least one small patch of his life, big industry at the same time removes many of his options and creates a lifetime customer.

We've seen the same thing in car advertising. Downtrodden and inadequate people are given superhuman powers -- powers over life and death in the case of the driver, whose super-car helps him steer clear of the unpredictable cyclist knocked into his path by a mere football from the footpath. The cyclist is clearly not in control of his destiny: the motorist is -- or at least could be -- if his destiny also involves forking out fifteen grand for the four-wheeled personality enhancement vehicle which is being advertised.

For a significant minority of inadequate car drivers the interior of a car is a private world where they can lay claim to a distinct and controllable space, where they can cultivate the gardens of their ego, fertilized with the artificialities of a thousand command-and-control car ads. The exhaust pipe is not the only source of car pollution. The minds of countless young males have been polluted by promises of spurious and destructive power.

The cyclist has other ways than the motorist to find space to be what he or she wants to be. The cyclist can find what Voltaire might have called a private garden of the soul. Yet that garden is the whole of nature. It's everything we pass through and become part of during our rides. The difference is that we don't subjugate nature for our own satisfaction; we're not in the hands of manipulative mind-benders who promise the very things they cannot deliver: freedom, individualism, escape and (in most crowded towns) unfettered speed.

In general, the bike delivers what it promises. False promises are difficult to make for a machine which is so transparent. And cycling is in many ways a very public act. A few weeks back I was visiting a friend in Lancaster. It's a city with magnificent countryside right on its doorstep, so we jumped on bikes and headed for the hills, following a roller-coaster road to the Trough of Bowland. I wasn't particularly dressed for a long ride and the borrowed mountain bike was a real pig, but I enjoyed every pedal stroke.

We were overtaken by citizens in their later middle age, the good honest people of Lancaster out for a quiet drive, many of them cultivating their own spirit gardens as they went along. I like to think that each time they saw a cyclist on the road, they remembered what cycling had meant to them in their youth and wondered about giving it another go. Or it might just dawn on the occasional command-and-control fast car freak that their could be more to life than imitating the heroes of action films.

It's hard to cultivate your garden if you're a cyclist, because you're inevitably a very visual and challenging detail of the social scenery each time you ride. Ironically, it is when you feel yourself to be a completely free and independent spirit, mixing it with the elements, that you have the most telling effect on other people's lives. Cyclists, like, organic gardeners, are redefining innocence.