Midsummer Day is one of the old pagan festivals which the Christian Church tried to pilfer in the Middle Ages. The Church succeeded with the midwinter festival, which is now Christmas, but it was less successful with the midsummer one, which became the not very widely celebrated feast for the birth of St John the Baptist. But the Church, bent on ideological monopoly, had another, more straightforward, means of countering the pervasive appeal of pagan nature-worship: condemnation and extirpation. In 1644, for example, the Puritans persuaded Parliament to ban the maypole as a 'heathenish vanity, generally abused to superstition and wickedness'. To this day, most of us associate paganism with something cultish, sinister and anti-social: with bizarre and probably orgiastic practices performed at unreasonable times of the day.
We should re-examine our prejudices. Few of us may be leaping through the Beltane bonfires this week or collecting St John's Wort to chase away the Devil, but the evidence of paganism surrounds us, and grows. Think of totemism - the 'primitive' identification of people with plants or animals, manifested nowadays by wearing T- shirts inscribed with emblems of whale, seal and panda. Think of the original (Latin) meaning of pagan - 'inhabitant of the land'. Since the 1960s, millions of people have abandoned cities throughout the Anglo-Saxon developed world in search of a better life in the countryside. The Travellers, perhaps as many as 60,000 (and growing), are merely the exotic fringe of this movement.
Consider, also, the size of the green movement. For all the claims that it is a spent political force, membership of environmental groups is put at about
5 million, up from 3 million since the mid-1980s. By contrast, according to the latest census of church attendance taken in 1989, 3.7 million adults go to church on an average Sunday, down 10 per cent in a decade.
Robert Runcie, the former Archbishop of Canterbury, is among those who have noted the appeal of environmentalism as a contemporary religious movement. William Temple, Dr Runcie's predecessor at Canterbury in the 1940s, wrote in Nature, Man and God that the human race was unlikely to correct its 'hideous' mistreatment of the earth unless it recovered its oneness with nature. 'Many people think this is fantastic,' he added. 'I think it is fundamental to our sanity.'
William James, the American psychologist and brother of the novelist, Henry James, would probably go further. Look inside his The Varieties of Religious Experience and you will find marvellous examples of the moment that changed people's lives. Here we have a Mr J Trevor, a Victorian cleric who has what we might now call an out- of-the-body experience on the hills near the Cat and Fiddle at Macclesfield in the Peak District. On a brilliant, sunny Sunday morning, Mr Trevor forsakes the family trip to the Unitarian chapel for a walk with his dog.
Suddenly he stumbles into 'Heaven . . . an inward state of peace and joy and assurance indescribably intense, accompanied with a sense of being bathed in a warm glow of light'.
For Rudolph Otto, the German philosopher and author of Das Heilige (The Holy), the essence of such experiences is that they involve confrontation with something 'ganz andere' - wholly other. From this perspective, the man-made world of church ritual and soaring Gothic architecture, while inspiring, is no substitute for nature: it is secondary and merely imitative. James's survey suggests that most religious experiences occur out of doors, amid mountains, sunshine, greenery. 'Religious awe,' James remarks, 'is the same organic thrill we feel in a forest at twilight or in a mountain gorge.'
Nature, in other words, is the raw material of religion - the psychic fuel that powers the religious impulse. In the Christian era - which, with less than one-tenth of the population attending church, can be said to be receding into history - the majesty of nature was seen as reflecting the majesty of God, who remained outside the visible world. Fewer and fewer of us believe that: we find nature to have sufficient meaning in itself. The recent Gaia theory, the idea that the earth is a kind of organic being, is a sign of that change.
What this means, in effect, is that we are all pagans now, whether we recognise it or not. Christianity, under the impact of theorists such as Teilhard de Chardin and bishops such as Hugh Montefiore, has long been going greener at the edges. Fortunately you do not have to be a paid-up member of the Christian ecologists or the ancient Order of Druids to derive pleasure - intense, life-enhancing pleasure - from a piece of woodland, a mountain view, or a wild creature. Nor, any longer, do you have to pretend it is something to do with God. The worrying question - of which the Midsummer shenanigans at Stonehenge serve as an obscure but regular reminder - is this: if more and more of us need nature for the good of our souls, what happens when there is less and less of it left?