The Democratic conventioneers will more than likely ask themselves the question. Everybody who comes here does. Sometimes they ask it silently, sometimes they blurt it right out: How can people live in New York City?

The folks coming to the convention that starts tomorrow will see a somewhat sanitized version of the town, of course -- the mayor and the cops will have pushed the prostitutes, the garbage, the sidewalk gamblers, the dope dealers and the shopping-bag ladies off to other parts of the city for the duration of the convention. They may even pick up the garbage and clean the streets in the immediate vicinity. Everybody will be on his tooth-grinding best behavior. But any visitor with the time and inclination to stroll from hotel to convention hall will almost certainly have cause to wonder: How can these people live in this place? And (in the case of those who could move if they wanted to) why do they stay in New York?

The question comes up almost everywhere -- in Atlanta where I used to live; in Raleigh, N.C., my hometown; from a lobsterman in Rhode Island; from an old boy with a grinning face full of catfish in Lake Okeechobee, Fla.; from a trucker on Channel 19 on Interstate 40 in New Mexico. I've heard it most, though, from people who live in and around Washington. This is not surprising, since New York and Washington compete with each other on numerous levels and since each maintains an ongoing, nagging curiosity about the other.

Having plugged away at the question in the past, I've found it best to begin with the bad news. First, New York is filthy. The trash and garbage in the streets are the first things a tourist notices, and the putrefaction is pretty depressing for us residents as well. I have never been in a city where there was less inclination on the part of government to pick up the filth. And the reason for this is the explanation for many of the city's problems: It is greed.

New Yorkers are among the most profoundly selfish people in the land. And when they band together into groups to promote and protect their selfishness, their greed assumes truly awesome proportions. This quality, which outside observers often perceive as typical New York "pushiness," has created a municipal bureaucracy, police force, medical establishment, sanitation department and retail clerk class that, with some but not enough exceptions, is shiftless, surly and arrogant, concerned solely with looking out for Number One and to hell with the job that they are paid to perform.

Our mayor is given to insensitivity, childish petulance and great bursts of harmful rhetoric. The Koch administration is roughly comparable in quality to early-evening television, and the mayor himself might well be called the Chuck Barris of municipal politics. He acts like a racist and he apparently enjoys humiliating people; he has lowered the quality of life here significantly and has been afraid to deal with hard issues that confronts the city.

The public schools churn out iliterates by the hundred thousands, as anyone can tell from the misspelled graffiti that covers the city (and from more high-class proclamations, such as Saks Fifth Avenue's show-window announcing "American Design at it's best").

A municipal ambulance driver got probation for picking the pockets of the sick and dying he was carrying to Bellevue. The city's judges are of a quality comparable to daytime television. The transit authority spends millions to slop paint inexpertly around the subway while people ride to work in unsafe equipment and in an ambience of stale fecal matter. The South Bronx is Dresden, and even the feds, who once thought it would be good campaign fuel, are trying to forget it's there.

In an atmosphere in which the fundamental rules are set by greed, criminality flourishes. Consumer protection is virtually nonexsistent. The police force is racist and marbeled with corruption, and many of its members are shiftless to boot. A lawyer friend of mine recently called the police emergency number, 911, when he discovered an elderly neighbor lying incoherent on the floor, the victim of a stroke. It was an hour and a half before the ambulance arrived. On another occasion the same friend encountered a young burglar in the front room of his Park Slope home. He physically held the intruder while he dialed 911. The police never came, despite his repeated calls, and he had to let the burglar go.

Many of our celebrated institutions, particularly those in the area of communications, are shockingly inferior to thier advertised images. New York's outlets for public television and radio are shoddy when compared to those of the most backwoods towns, and The New York Times has abandoned the city in favor of stories on the order of what Mimi Sheraton's mommy used to fix for dinner and what to do if your au pair girl loses a finger in the food processor.

New York is an environmental tragedy. Faced with federal orders to clean up its rotten air, the city has proposed a series of phony programs embarrassing even to the bureaucracy. New York was built on the water, but its citizens have little access to it. The water we drink is clean and sweet, but the system that brings it down from the Catskills is collapsing.

What is worst of all for us is that New York's greediness, selfishness and rudeness have made me greedy, selfish and rude. When I'm in Washington or Virginia or Santa Fe -- any place where the competition for time, space, money, privacy, and power is not so great -- I find myself becoming les pushy and obnoxious, more tolerant. I can watch almost in amusement as someone nudges into the supermarket line in front of me. When the same thing happens at my local grocery, an urban battleground where the unit pricing law is ignored and where I have caught them mislabeling chicken and selling outdated milk, I am as likely as not to make a loud scene.

I think the reason for the difference is that in New York much of your time is spent in trying to hurry through overcrowded, unpleasant situations so you can get back to your own little triple-locked cell, where you can escape millions of other greedy, rude, intolerant people. Look at office workers on their lunch breaks: fully 5 percent of them are blowing grass as they walk down the sidewalks -- not for fun, as God intended grass to be smokd, but so they can get through the day. They are scowling as they consume their skinny little joints. For all their attention to self, New Yorkers are not, as a rule, happy people.

It is, when you think about it, a pretty unsatisfactory existence. When you add on Con Ed, the telephone company, the dog-droppings and the caprices of New York State (our government has the charisma of a used teabag), it becomes almost unbearable.

There. That felt good. There's nothing a New Yorker (after 17 years, I qualify) likes better than to talk bad about New York City. And that's just a parital list.

"It's so dirty ," say the people who want to know why someone choosess to live here. "Every time we go there it seems filthier," say my friends in Washington. "Compared with L.A.," said a Californian, "it's a garbage can."

Comparisons, of course, are what it's all about. Los Angeles is frequently mentioned, but as cosmopolitanism has brought bean curd, pita bread and live music to towns once to small to host Tupperware parties, a number of cities have emerged as serious revals to New York. And they can offer amenities -- a more civilized attitude, cleaner air and streets, higher-grade poliitcians -- that you can't get in the Big Apple. Washington, particularly, has the amenities.

I like Washington: It comes very close to New York in the serendipity category; it is relatively easy to get from the capital out into not-very-spoiled nature, and it may be the most racially intergrated city in the nation (although a long way from perfection) and I am bone-tired of segregation and all its awful byproducts. In Washington you can really celebrate the arrival of spring, everything grinds to a proper halt when ther's a little snowfall, and you can ride a bicycle without getting run down by a taxi driver for sport. aWashington's confidence in itself, and therefore its sexiness, seem to have grown as the city has matured and (perhaps more importantly) as it has become the financial turstee of the errant, aberrant city to the north. I like Washington, too, because it's fairly close to New York City, and a lot of my friends there come up here a couple of times a year to get transfusions ("fixes" are what they universally call them) of whatever it is that draws people to New York.

But I continue to dodge the question. What's good about the place? Well, two good things about living in New York are that it isn't Dallas and it isn't Houston. And a New Yorker who has nothing else can still rise every morning and thank God that he or she isn't a Philadelphian.

The point most often made is the enormous degree of access New Yorkers have to things cultural -- to the Broadway stage, the dance, music, art, museums -- although I admit that I, along with most of my citymates, patronize these attractions only rarely. But that's not the real point. the real point is the knowledge that it's there for you to take you want it, and it isn't there if you live in Baltimore of Chicago (even though diehard New Yorkers are starting to notice that it's getting to be there in Washington).

Of much greater importance to me, and I suspect to a lot of the others who remain in this crumbling anachronism, is another attraction, one that I patronize every day. And that is New York's ehtnic diversity. The Irish, Italians, Jews, Poles, blacks, Mohawks, India Indians, West Indians, Puerto Ricans, Cape Verdeans, Filipinos, Chinese, Scandinavians and even my own tiny minority, the white Southerners, a.k.a. crackers, have never melted into the pot, thank godness, and I see no signs that they ever will. It is they, and their neighborhoods and tastes, and the ways their faces are sculpted and their minds and attitudes shaped, that make the difference between a city that's worth living in and one that isn't.

Lots of cities, particularly older East Coast ones, have ethnic diversity, but I know of none where the idea of neighborhood is so important and where the neighborhoods are so wide open to everyone's inspection. If you walk into an ethnic neighborhood in Philadelphia or Boston, you're as likely as not invading someone's territory. More individual ethnic classifications may probably be found in Washington. Most of their representatives, however, may be observed not in neighborhoods, but in limousines on their way to embassy parties. New York's ethnics are here, by and large, because they were fleeing the sort of people who ride in limousines.

It is in New York's neighborhoods that you can find the foods and clothes and customs which succeeding generations of exiles have blessed the city. That's where you feel the humor and rage and passion of all those people, bound together by few things other than the fact that they all live packed too closely together in a geographical, political and emotional entity known as New York City, and that they therefore share a feeling of common destiny. Or perhaps it is one of common doom.

You can see all this diversity at stree level because New York remains essentially a walking town. This fact will become even more attractive as the domestic oil cartel deepens its gouges, and it is one that my friends in more cardependent cities have mentioned to me with more than a touch of jealousy.

I use shoe leather, in conjunction with the sewer (my friendly little name for the subway), as my prime means of locomotion. It is the ideal way for treating yourself to the endless theatrical performance that is life in New York.

Take a walk, especially on one of those extremely rare days of early summer or fall when the sky s very clear and the mortar is sharply defined along every brick and the shadows are translucent on every wall. Go to the Village, which always has been the best place for mask-wearing -- protecting your privacy by hiding behind whatever facade you choose. SoHo was pretty good, too, until the people with money and little else started buying up all the lofts. And Bedford-Stuyvesant, a black ghetto as big as Toledo that people are rebuilding with their own hands and precious little help from their government. And the Upper West Side, where young Jewish intellectuals with very white skin and very black beards walk about in Greek fishermen's caps; and the Lower East Side, were a half-hour stroll can take you past kosher pizza parlors, places that sell butcher block by the square foot, and stores that specialize in home wine-making equipment, where you can be knocked flat by the foul breath issuing from the front door of an old Irish bar at 10 a.m.

And you can turn into the East Village, where some of the late-'60s hippies celebrated their brief Summer of Love, and see that not much love has remained. And walk past the place where the Filmore East was, where I once heard The Who do the real version of "Tommy." The theater's marquee is gone, its entrance cinderblcked beyond recognition, and next door is a store that advertises "We Sell COLD Perrier Water. "In it is a young man, bearded and wearing a Grateful Dead T-shirt, and I calculate that he must have been about the right age for the Summer of Love. He is carrying, in 1980, a six-pack of expensive imported drinking water.

So neighborghoods change, just as generations do. I happen to like the bittersweet ambience of a place like this, a place that has been one thing and is still deciding what it's going to be next. But some people don't like it. If You'r e one of them, take the IRT a few stops uptown and drink your own imported water (or even domestic) with a bag lunch at a little white table with fresh flowers on it in the open-to-public atrium of the Citicorp Center. A bank , yet, and it is one of my favorite places in the city, right up there with the graveyard at Trinity Church. Or sit on the steps of the 42nd Street Library at lunchtime and watch a ventriloquist, or walk anywhere in midtown and watch the Three-Card Monte artists fleece the suckers in absolute assurance that they won't be hassled by spoilsport cops.

Or you can walk a little farther downtown and you'll be in Little Italy, and then Chinatown, both of them incredibly filthy but both of them also incredibly alive. And if your feet are still in good shape, you can mount the Brooklyn Bridge and take your life in your hands (for the cops will not protect you) and walk across the East River into Brooklyn, where I live.

It is my own neighborhood, I think, that most seriously challenges my periodic resolutions to get the hell out of New York, to move to Washington, D.C., or Washington, State of, or Madrid, N.M., or, best of all, to a sailboat. o

My neighborhood is a community of brownstones in what is called South Brooklyn, and it stands about a mile and a half from the eastern ramparts of the Brooklyn Bridge. It is predominantly Italian-American and not much "gentrification" has occurred because the historical homeowners have not scared easily. Within a sixblock radius of my house there are four Italian bakeries which produce long, crisp loaves in batches throughout the day (when you carry it home it is still hot in your hands); a fine old man who sharpens scissors and knives and things like that; dozens of Spanish stores where you can buy everything from green bananas to entire pink piglets; a dry cleaner who will sew on a button and when you ask him how much, he will make that "gedovdzhesh" gesture; a man who will do an honest job of fixing your television set; two produce stores where nothing is wrapped in plastic and where you can get eggplant and scallions year round. And a fish market that sells all the usual stuff plus squid and conch; a longshoremen's hall and medical center where the men stand around all day discussing their hernias; and a small park I can walk through any hour of the day or night.

All of this is available, of course, on a year-round basis, but it really assumes majestic proportions in the warm weather, when people are out on the street. And that's when the block parties and street festivals are held, too -- the really true, sincere affirmations of faith in city living.

A few blocks to the north of where I live is the middle eastern trading center of Atlantic Avenue, where you can get handmade pita bread and 200 herbs and spices and your choice of a dozen fine, inexpensive restaurants. One of my neighbors has planted a dozen poplar trees in our common back yard, where we have taken down the fence, and it is possible to sit back there, or even glance out a window, and engage in fantasies of pastoralness. Another neighbor keeps racing pigeons on his roof, and they practice aerobatics every day, free of charge.

Court Street, which connects the edges of a number of neighborhoods, is where we shop. Because of the way New York is laid out, we engage in the wasteful but pleasing practie of buying food from day to day. I enjoy the ritual of dropping in on neighborhood businesses to catch up on the gossip, and many of the store-keepers have become friends in the dozen years we've lived here.

I didn't realize how close the friendships had become until Romeo's closed. Romeo's Food Center, a block from my home, was a small but well-found grocery store owned by the Romeo family -- Rose, the matriarch, her sister Fran and her brothers Joe and Bruno. In addition to all the usual staples, American and Italian, Romeo's provided me with hamburger ("chopmeat," they call it here) that Joe ground before my eyes and that tasted better than sirloin; sausages (hot, sweet and cheese) that Joe made himself; a charge account and check-cashing service; a place that inquired after, and apparently cared about, my health and the progress of my work; free delivery; advice on what Rose thought -- no, knew -- was the proper way to make eggplant parmigiana and pasta with pesto. And, it turned out, real friendship and even (dare I mention the word in the harsh setting of the Great American Free Enterprise System?) love.

Early last summer Joe told me they were closing. Bruno had been sick, and it was getting increasingly tiring for the rest of the family to run a busy store 12 hours a day, six days a week. "I figured it out," said Joe. "I haven't had a vacation in 40 years. Forty years. Think of that." I found myself agreeing that they had to close, no matter how mu ch the departure might disrupt the lives of the rest of us.

There was a good deal of disruption. Between the time the customers found out about the Romeos' plans and the time the doors were closed it was like mourning at 317 Court St. Some of the customers cried when they found out. Romeo's has been closed for a full year now and a part of my life is still confused. I still am shopping around for a new store -- no real problem, since there are three others within a couple blocks -- but there is little joy in the search. It is like going out and trying to find a new friend to take the place of one who has gone.

The closing of a grocery store has affected my life to an unexpected degree, particulary considering all this has taken place in the city that's the capital of human greed for the free world, the center of surliness, fountainhead of filth and paragon of pushiness. But now that I've thought about it, I realize my feelings about Romeo's, and about other aspects of life in my neighborhood, have everything to do with my feelings about New York.

I guess if I had to boil it all down into one word, it would be hope. That's what keeps New York people going, and that's what keeps me and a lot of other people from leaving. You hope, perhaps in vain, that things'll get better, that this absurd involuntary experiment in mass urban living will work. You are heartened by little signs of continuity, for continuity means hope: At about the time you start to detect a decline in old-fashioned, mom-and-pop produce markets, you notice that Korean families are getting into the business, and that they seem to be taking special care to present their fruits and vegetables attractively. Indians are taking over the newsstands in the subways, and many of them say "Thank you" when you spend money with them -- a revolutionary gesture that may not last but that's pleasant while it's here.

Those who would promote New York have flooded the place lately with T-shirts that proclaim varying fealties to the city. (This may be a good sign, for so great has been its lack of humility in the past that New York rarely has felt it necessary to pay for publicity.) Boroughs and neighborhoods have come along with their own insignia. I, myself, prize a T-shirt that depicts a fine old tree and, down there amongst its roots, the word "Brooklyn."

Well, the other day I was walking along Canal Street, which is one of the finest places I know to do simultaneous open-air shopping and people-watching, and I saw a young man wearing a T-shirt that said "That South Bronx." He didn't look particularly happy; in fact, he looked sad. That should not have been surprising, considering the past and present of that ravaged part of the city. But he must have had some hope for its future or he probably wouldn't have been wearing that T-shirt. His hope spilled over to me, and I found myself feeling especially good about New York for the whole rest of that day and well into the next.