Standing in Melbourne airport on the day before this year’s World Science Fiction convention, I found myself playing the familiar road-game known to all who travel to cons: spot the fan. Sometimes, ‘‘spot the fan’’ is pitched as a pejorative, a bit of fun at fannish expense, a sneer about the fannish BMI, B-O, and general hairiness. But there are plenty of people who are heavyset, and practically everyone debarking an international flight to Melbourne is bound to smell a little funky, and beard-wearing is hardly unique to fandom.

If there is one thing that characterizes fandom for me, it is a kind of cosmopolitanism. Now, we tend to think of ‘‘cosmopolitan’’ as a synonym for ‘‘posh’’ or ‘‘well-travelled.’’  But that’s not what I mean here: for me, to be cosmopolitan is to live your life by the ancient science fictional maxims: ‘‘All laws are local’’ and ‘‘No law knows how local it is.’’ That is, the eternal verities of your culture’s moment in space and time are as fleeting and ridiculous as last year’s witch-burnings, blood-letting, king-worship, and other assorted forms of idolatry and empty ritual.

One of science fiction’s greatest tricks is playing ‘‘vast, cool intelligence’’ and peering through a Martian telescope aimed Earthwards and noticing just how weird and irrational we all are. At its best, science fiction is a literature that can use the safe distance of an alien world or a distant future as a buffer-zone in which all mores can be called into question – think, for example, of Theodore Sturgeon’s story of the planet of enthusiastic incest-practitioners, ‘‘If All Men Were Brothers, Would You Let One Marry Your Sister?’’ published in Dangerous Visions in 1967.

Behind every torturer’s mask, behind every terrible crusade, behind every book-burning and war-drum is someone who has forgotten (or never learned) that all laws are local. Forgetting that all laws are local is the ultimate in hubris, and it is the province of yokels and bumpkins who assume that just because they do something in a particular way, all right-thinking people always have and always will. For a mild contemporary example, consider the TV executive who blithely asserts that her industry is safe, because no matter what happens in the future, the majority of us will want to come home, flop down on the sofa, and turn on the goggle-box – despite the fact that TV has existed for less than a century, a flashing eyeblink in the long history of hominids, most of whom have gotten by just fine without anesthetizing themselves with a sitcom at the end of a long day.

Which is not to say that cosmopolitans don’t believe in anything. To be cosmopolitan is to know that all laws are local, and to use that intellectual liberty to decide for yourself what moral code you’ll subscribe to. It is the freedom to invent your own ethics from the ground up, knowing that the larger social code you’re rejecting is no more or less right than your own – at least from the point of view of a Martian peering through a notional telescope at us piddling Earthlings.

My high-school roommate, Possum Man, was the very apotheosis of a science fiction cosmopolitan. Educated in the radical (and quite wonderful) Waldorf school system, Possum decided that quantitative grades and credits cheapened the learning process. So even though he took a full roster of courses, he rejected all grades and credits for his (quite excellent) work, and never received a formal diploma despite a long and honorable career in our alternative secondary school.

Possum was willing to reconsider anything and everything from the Martian distance. One day, he noticed that the insides of his knit sweaters were much more interesting than the outsides – busting with tasty asymmetries and pretty loose ends, a topography that was far more complex and chewy than the boringly regular machine-made exterior. From that day forward, he started wearing the sweaters inside out. (Today, he helps coordinate Toronto’s free school, AnarchistU.)

Which brings me back to spot-the-fan. Looking for fans isn’t just about looking for heavyset people, or guys with big beards, or people who are sloppily dressed. Looking for fans is about looking for people who appear to have given a great deal of thought to how they dress and what they’re doing, and who have, in the process of applying all this thought to their daily lives, concluded that they would like to behave differently from the norm. It is about spotting people who are dressed as they are not because of fashion, nor because of aspiration, but because they have decided, quite deliberately, that this is the best thing for them to wear. (Before I go on, let me hasten to add that some fans are simply bad dressers with poor hygiene and grooming – but that’s hardly the exclusive province of fandom or any other subculture).

There’s something comforting about cosmopolitanism, especially if you start off as someone who’s a little bit weird or off-kilter. Cosmopolitanism comforts you with messages like, ‘‘The head cheerleader and the quarterback may rule the school, but they have no more virtue than the peacock with the biggest feathers, the goldfish with the bulgiest eyes, and in most of the cultures that ever existed, they would be thought ugly, stupid and ridiculous.’’ The haughty distance of cosmopolitanism lets you avoid the misery of the daily, earthly reality of being a social pariah – I may be a Martian, but at least I can look down on all of you from Mars and see your absurdity for what it is.

And once you start, it’s hard to stop. Reading Patterson’s recent biography of Robert A Heinlein, Learning Curve, I was struck by how much fringey stuff old RAH dabbled in: telepathy, radical politics, polyamory (or ‘‘companionate marriage,’’ as it was called in his day), nudism, and all manner of funny business, all of which is reflected in his books, and all of which can be summed up with ‘‘all laws are local.’’

That takes me to the Web, and to ‘‘Rule 34’’: ‘‘If it exists, there is porn of it. No exceptions.’’ (Charlie Stross has recently completed a book called Rule 34, which sounds like a hoot). Rule 34 can be thought of as a kind of indictment of the Web as a cesspit of freaks, geeks and weirdos, but seen through the lens of cosmopolitanism, Rule 34 suggests that the Web has given us all the freedom to consider that the rules we bind ourselves by are merely local quirks, and to take the liberty to turn our sweaters inside out, practice exotic forms of vegetarianism, or have sex while wearing giant anthropomorphic animal costumes.

Rule 34 bespeaks a certain sophistication – a gourmet approach to life. As Kevin Kelly points out in his excellent new book, What Technology Wants, a gourmet isn’t someone who shovels everything he can get hold of into his gob; rather, it’s someone who looks long and hard at all the available options and picks the ones he finds best. Kelly’s definition is an important one, because it provides a roadmap to a sophisticated approach to any product or practice; for example, this definition makes the Amish into the world’s greatest technophile, since the avant-garde of Amish hackers try every new technology, evaluate whether it fits well into Amish life, and report back to the wider community who decide whether and how to adopt the tool or service based on what it is likely to do to their lives. While the rest of us are gobbling up new technologies like they were $0.99 Super Big Meals, the Amish are carefully tweezering out the best bits and leaving the rest behind.

Rule 34, the Amish, and fandom’s willingness to wear its sweaters inside-out are the common thread running through the 21st century’s social transformations: we’re finding a life where we reevaluate social norms as we go, tossing out the ones that are empty habit or worse, and enthusiastically adopting the remainder because of what it can do for our lives. That is modern, sophisticated, gourmet cosmopolitanism, and it’s ever so much more fun the old cosmopolitanism obsession with how they’re wearing their cuffs in Paris, or what’s on at the Milan opera.