Yet the process of inhalation and exhalation are very similar to the process of love; both involve the refinement of useful substances from a pollution-rich medium, both involve the consumption of what is good, and both involve the eventual disposal of what remains. Coal is no use, if it is not burned; like oil, it is not worth preserving in itself, it is good that we dig it from the ground and burn it. Yet the chemicals so released enter the air, where they are of no use at all, except to strengthen and test my pleural membranes.

And that is love. I remember a few years ago, when the actor Charlie Sheen was involved in a court case involving a lady called Heidi Fleiss, a madam. Several writers wondered why Charlie Sheen - a relatively wealthy, relatively famous and relatively good-looking film star, blessed with the genetic material of his father, Martin Sheen - they wondered why Charlie Sheen would need to hire prostitutes, given that he would presumably not have difficulty attracting women to his undoubtedly large house. The reason given was that, for many men, the appeal of a prostitute is not that she arrives on time and performs unspeakable acts; it is that she eventually leaves, she can be dismissed on command. It is said of butchers that they can cut, mash, sell or use every part of the pig, except for the oink. The same is true of love.

Love is not like that. It is rather like hiccups, in that it takes a major event to prevent its recurrence. Without a traumatic shock, the hiccups continue, because they are not under conscious control of the body. As with nosebleeds and milk teeth, they are a continual reminder that our minds are merely passengers in a vessel which cannot be controlled and which is driving towards the edge of the world. Although many have mutinied - particularly the psychedelic experimenters of the 1960s - no-one has yet managed to install a lasting revolution. Our bodies are an amalgam of banana republics, but armed with nuclear weapons, and built on fault lines. The plates will shift, they will shift one day.

Love is the process of sucking smoke-filled air through gauze. It suffocates, and the end result is a dirty piece of gauze. It is not pleasant, and we watch as the gauze becomes ever-more filthy, and our doom approaches. Without it we would die. Desire draws me on, and fear pushes me back. Heroin itself is not harmful, instead the harm comes from society's reaction to the drug, and from the fact that someone who is in love with heroin is unable to look after and feed himself or herself, and to afford or procure the drug. We all need someone to nurse us, and that is love as well. There is so much love which is not in itself harmful, but which is unacceptable to society at large; or which is too expensive for the limited resources which most people command. Yet I must never speak of this. I was young, myself.