By Kristine McKenna, 4/5/2002

IT'S AMAZING what it's OK to do in public these days.

If you need to blow your nose while walking down a city street and find yourself without a tissue, it's OK to press on your left nostril, lean to the right, and blow hard out of your right nostril. I've seen this nose-blowing technique performed with considerable aplomb several times.

Not only is it OK for your cellphone to ring as the casket is being lowered into the ground at a funeral, it's OK to take the call.

Whereas business attire was once de rigueur for air travel, wife beater T-shirts are now OK, and once your plane is airborne, it seems it's OK to unbutton snug trouser waistbands, remove your shoes and pad up and down the aisle in threadbare socks. It's also OK to pack your travel gear in a Hefty bag and drag it on board with you.

Leaf blowers are illegal in many communities, but it's still OK to use them, at least in my neighborhood. And, yes, it's apparently fine if you go away for the weekend and leave your three dogs in the backyard to bark nonstop for 48 hours, as my neighbors recently did.

What all these instances of infantile narcissism share is a failure to grasp the fact that the world is a small place. There are lots of us crammed together, and there are aspects of the world we have to share. When occupying public spaces - or even when within earshot of others - we would do well to remain respectful of issues involving body space, eye contact, sound, and smell. No one has the right to pollute these shared spaces, whether by driving in a car blasting music at a decibel capable of triggering seizures, throwing trash on the ground, or screeching into a cellphone.

More annoying than the sound cellphone users make is the subtext of this activity. Essentially, a person on a cellphone is saying to everyone around him, ''I'm not here inhabiting this space with you, we are not together, I am someplace else.'' This incredibly antisocial message is a complete negation of the notion of community and is also a way of not being fully present in the world. The world's an interesting place. Let's show up for it and pay attention.

If you're thinking of heading for cyberspace in an attempt to escape the madding crowd, don't bother - things are bad there, too. When a friend sends you one of those blanket e-mails that's also been sent to 20 other people, don't you feel as if you've been demoted? I always scan the list of fellow recipients and think, ''Oh, so this is how I rate.''

''It's a way to stay in touch in a busy world,'' protest those multi-tasking spammers, but a mimeographed memo is not my idea of communication. If you're not convinced of the depths of cyberspace gaucheness, just check out Roger Clarke's 1995 typology ''Net-Ethiquette: Mini Case Studies of Dysfunctional Human Behavior on the Net,'' which covers such things as ''flaming,'' ''trawling,'' and ''spidering'' along with the ultimate in what he terms ''power rudeness'' - firing someone by e-mail. Nice, huh?

While evidence seems to abound that man is rapidly creeping back to the primordial ooze, in fact, the ever-shifting code of etiquette we cling to in an effort to perceive ourselves as civilized creatures is constantly in the process of breaking down. The offenses listed above represent nothing more than how it's breaking down right now.

It's tempting to romanticize the past, to think of it as a sort of endless ''Sunday Afternoon on the Island of La Grande Jatte,'' the signature work painted by Georges Seurat during the years 1884-86. In this romantic vision, life used to be a choreographed social minuet in which beautifully dressed, impeccably polite people enjoyed interacting.

Although wealthy people lived more formally in Paris 150 years ago, they also engaged in behavior that would strike us as weird today. Most of the rules that have governed public conduct for centuries originated in the French royal court in the 16th and 17th centuries, and while some of them still make sense, others have become obsolete. Children were once taught the proper way to kneel before a teacher and to remain silent until spoken to, but they were also taught how to use a pointed dinner knife as a toothpick.

When people began reading in public shortly after the industrialization of literature in the early 19th century, it was considered downright thuggish, just as when people first started walking around plugged in to Sony Walkmans, they were often perceived as hostile and remote. Neither activity raises an eyebrow now.

My mother nursed her children with a cigarette hanging out of her mouth, and so did most of her friends. Driving drunk was once considered not that big a deal. It's unlikely such behavior would pass without sterner condemnation now.

What constitutes acceptable behavior is clearly a kind of a one-step-forward, one-step-back situation. We've gotten smarter about some things, but we've gotten wretchedly grubby about others.

The guy at the next restaurant table is no longer allowed to light up a cigarette, but he may go outside and blow his nose on the sidewalk. Granted, that nose-blowing isn't endangering anybody's life, but it hardly seems a mark of social progress that people have come to feel at liberty to do it. Somebody needs to rework the rule book.

Kristine McKenna wrote this column for the Los Angeles Times.

This story ran on page A23 of the Boston Globe on 4/5/2002.
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