A science fiction writer needs two things: a wild imagination, and a suspicion that the world is not what it is commonly presumed to be. These two qualities are in addition to the usual writer's items of equipment, such as egotism, endurance, and a loyal wife or husband.
Establishe d writers are often asked, "How do I become a writer?" But becoming a writer is child's play compared with remaining a writer. To go on creating, and enjoy creating, and not lapse into formula, is a rare talent (or a piece of good fortune). Which is where the medium of science fiction is such a help.
In its popular origins, in pulp magazines in the Twenties and Thirties, SF existed mainly in the form of short stories, "novellas", or serials. It was the paperback revolution of the Fifties that gave rise to the popular SF novel. But SF magazines survived, and are still publishing. Their circulations are modest, as are the fees they pay writers. But they encourage a variety of story lengths.
This means writers can change their pace, from the slow-cook rhythm of the novel form to the brisker progress of short stories. One thousand words or 30,000, the magazines will usually welcome them. The short story is a precious and under-estimated creature.
But how do you define SF? Well, stories have to contain at least an element of divergence from the world we know. Or they can be set in that convenient grey area, "the future". Or they can be about a scientific developmen t, or the effects on society of a scientific development.
The very label "science fiction" warns the budding writer that he is dealing with a hybrid. You need to read a good deal in the genre to decide on the mix that suits your talents. You do not have to be a professional scientist. In fact, few scientists write SF, the most famous exception being Fred Hoyle, whose celebrated novel, The Black Cloud, appeared in 1957.
SF writers may have a scientific background. They generally nourish a restless conviction that change is all about us, with more to come. Some of those I have most enjoyed are satirists, who use spaceships and computers much as Western movies use horses, as picturesque plot devices. Good examples are Frederik Pohl, Damon Knight, Robert Sheckley, Margaret St Claire, and William Tenn. Their stories are witty social commentaries. I never understood why such writers are not enjoyed by a wider audience, and better known, although certainly Frederik Pohl has his share of fame.
Many SF stories are conceits in the old literary meaning of the word - elaborate exaggerations or far-fetched images designed to illuminate contemporary trends, feelings or dangers. As such they fulfil the same function as, say, Orwell's 1984 and Animal Farm.
But science is the bedrock of SF. I've given up counting the number of science articles on cloning, genetic engineering, materials design, robotics, or cosmology which begin, "What used to be science fiction is now . . ." We do pride ourselves on trying to get the science right. or at least plausible. I just wish we prided ourselves more on getting the writing right. SF has become very commercial; many authors make big bucks from it, so big that neither author nor editor cares greatly for the style in which the product is presented.
I have my own rather cranky theory about the joys of SF. A running argument within the genre is being fought between the "Hard SF" authors, such as Gregory Benford, and the "Soft SF" authors, as to which is the more authentic brand. This battle is being fought in the wrong field. The intellectual pleasure we derive from an SF novel or story is that we have to determine whether what we are being told is within the bounds of the possible or is just fantasy. We can enjoy this tease whether the story is loaded with robots and machinery or set in a mutated cabbage patch.
This literature of change is changing rapidly. It allows a new writer plenty of scope. The biggest change came not from new technologies but from the good old printed page, when Tolkien's Lord of the Rings was published in the mid-Fifties, to become a cult campus book for many years. The idea of archaic, imaginary, and inaccessible worlds proved attractive. Imitators, the planetary romancers, swarmed into the field. Among those influenced by Tolkien's methodology are such well-known names as Stephen Donaldson, Marion Zimmer Bradley, and David Eddings. These authors have produced long series of books, of which Bradley's Dark Over books are best known.
Developing technology has brought more change. Arcade games, computer games, and blockbuster movies have increased the influence of SF without necessarily extending its range of ideas. The film Waterworld, based on the fact of global warming and melting icecaps, abandons its premise for colourful action adventure - the prime ingredient for films which must recoup a $70 million investment. Your true SF buff regards such waste with contempt, even while enjoying the archaic-type machinery and the explosions. It is the same with Jurassic Park: the dinosaurs are wonderful and the plot inane.
Yet clearly much thought had gone into Jurassic Park. In an age when genetics and bioengineering have a vital future, the question the film raises, of whether an extinct animal might be recreated from the DNA held in the stomach of an insect embedded in amber, is of interest to more than the cinema-going public, and has provoked much serious discussion.
Here was a case where we were teased to wonder if the central idea was within or beyond the bounds of the possible. With a little more education, a better understanding of scientific principles, we might be better placed to decide.
I had a vivid illustration of this when my three novels about the planet Helliconia were published. Helliconia is a planet in orbit about binary suns. A learned Oxford friend praised my story-telling abilities before saying, "But you couldn't really have two suns in the sky, could you?"
I had taken the idea of binary suns for granted, a rather elementary astronomical fact; I had believed myself to be writing science-based SF, whereas a reader took it for fantasy.
A recent poll taken in Britain and the US revealed that almost half the population of both countries believes the Sun goes round the Earth. It is extraordinary that, so close to the millennium, so many still live under the old Ptolomaic system, simply because the orbiting of the Earth about its primary seems to violate the common sense everyday experience. While it is hard to see how the geocentric mind can sustain itself after the reality of space travel has appeared on our TV screens, it provides an explanation for the hostility towards science and science fiction. In this respect, they are up against the same thing: a fear of novelty. Accustomed to one system, the average punter dislikes having to discard it for another.
SF is a passionate embracer of new systems. Let it be worse than the present one, as long as it is different! But SF is somehow regarded as beyond literary consideration. In fact, it is the true literature of our murky century, and has played a part in the Cold War and the collapse of the Soviet system.
Some of today's most brilliant exponents - let's say Iain M Banks in Britain and Greg Bear in the States - vibrate with energy and imagery. And, despite the poor quality of some fictions, those of us involved in the field remain fired by the platonic image of the literature of the futures into which we plunge.
Most publishers will publish science fiction, not always labelling it as such. Beginners are best advised to submit their novels to publishers who have a specialist SF list. The best British magazine for short stories is Inter zone, which receives an Arts Council grant and is published in Brighton.
* Brian Aldiss's latest book, a collection of essays, The Detached Retina,is published by Liverpool University Press
* Next week Jonathan Myerson on writing for television series such as The Bill
* The Arvon Foundation runs highly respected creative writing courses at centres in Devon, Yorkshire and Scotland. The first 10 readers to send a TES masthead together with their address to David Pease at The Arvon Foundation, Lumb Bank, Heptonstall, West Yorkshire HX7 6DF will receive the new Arvon brochure in January and 20 per cent off the course of their choice