If all goes well, any adventure into love, headlong or hesitant, may seem an obvious and simple matter. Yet it is not simple at all, for it is entangled with all the greatest influences that bear on humanity. The vast network of social and cultural pressures under which we live our lives; depth-psychology, social psychology, cognitive psychology; the driving forces of our evolutionary ancestry; the physiological urges of our sexual bodies - all contribute to what may often seem to be an exciting but uncomplicated event.
The relationships of these pressures is a matter of hot controversy, between (at one extreme) those who believe we are born not made, and who see failing in love as a "natural" innate behaviour; and those (at the other extreme) who believe we make our own destiny, and regard love as a cultural construct, varying in nature and significance at different periods. There are some who assert that love would not exist at all if we did not name it so. All that is agreed is that falling in love is intense, absorbing, ecstatic - and brief.
Whatever the answers - which must surely lie in a combination of these views - love continues to fascinate us, and the emotion, time and ink expended on it has changed little in at least 3,000 years. For this is an ancient experience, and those who assert it was created by the 12th- and 13th-century troubadours of Provence are looking not at a new experience but at the intensification of an old one, fraught with a new inward significance.
As to what is happening when we fall in love, explanations are as various as the experience itself. Are we simply responding to sexual urges suffused in romance? Are we engaged in reconstructing our infant experience? Or are we only following the expectations of our culture? Could it be that we are simply repeating the "imprinting" of infant birds and many mammals? Or are we irresistibly impelled by the archetypes and "love-maps" lurking in the unconscious?
As to why this experience should ever have evolved, when it appears nowhere else in the animal kingdom, we have to decide if it arose chiefly to provide a close parental bond for the rearing of the remarkably helpless human infant; or as an attempt to combat human loneliness, isolation, anomie; or as a device of patriarchy to encourage the control of women and ensure the proper descent of wealth. Or as a combination of these and possibly other pressures. There are no easy answers. Although we surmise endlessly, we still know very little of our wondrously intricate minds and brains.
It is still customary to seek and celebrate and extol the raptures of failing in love - but not everyone approves it. No one could question that it can produce agonies and treacheries and entrapments every bit as consuming as its joys and loyalties and freedoms, and there is strong opposition stirring against love's slavery selfishness, blindness, and a growing conviction that its excesses could be tamed, by knowledge and reason, into a new alignment of sex, honesty, and companionship.
For those who see our basic emotions as ancient, intractable stuff, this may seem an over-optimistic view - yet perhaps we are not helpless. The unravelling of confusion offers a chance of deeper understanding, and through that it should be possible to find attitudes to love more aware, more alert, more ironic.
Sheila Sullivan is the author of `Falling in Love' (Macmillan, pounds 14.99)