Anyone old enough to remember the Horatio Alger stories of bedraggled lads rising to fortune, or current enough to have heard the beer commercial that says you only go around once, will understand.

Somewhere between Alger's paeans to capitalism and Joseph Schlitz's appeals to get it while you can, there is a sobering enlightenment

Jan Cassidy feels it. So do Eriskia Smith and Julene Pasour. All three have worshipped at the altar of acquisitiveness, but each has had a crisis of faith. No longer is life as simple as the jingles have it, or as easily shaped by Alger-inspired ambitio.

Cassidy, a nurse in suburban Washington, used to own 40 pairs of shoes. She can't afford such extravagance now. Smith, a $13,500-a-year Air Force sergeant in Duluth, had to dump his second car, a Buick Electra 225. Expenses got so high for Pasour, a Charlotte bank teller, that she couldn't show her prize quarter horse at the state fair this year.

Times are tough, no doubt about it. But wait a minute. Forty pairs of shoes? A Buick Electra? A pet quarter horse?

Keep them in mind when you come across, as inevitably you will someplace else in this newspaper today, a story about the rocky American economy.

There is no argument that the economy is under real stress. Inflation is running near 14 percent, and wage increases are generally lagging behind that. Less money finds its way into savings accounts. Prime interest rates are up, and productivity is falling. Oil imports drain away more dollars. Other traditional indicators tell of instability.

On their face, these statistics are worrisome, and they ought to be. Many Americans, caught in the income-price squeeze, are forced to get along with less and to readjust their taste -- it's tuna for dinner when it used to be tuna for lunch. Others work longer hours and take second jobs just to stay even.

Some never had much hope to begin with, but for most it was not supposed to be that way. "Things are so tight for many of the older people in my district," Miami Rep. Claude Pepper (D-Fla.) said recently, "that their biggest decision in the morning is whether to buy a cup of coffee or a newspaper."

At the other end of the scale, where such meanness of life is unknown, enlightenment comes in a different wrapper. Millionaire Herbert Allen Jr., who runs the family-owned Allen & Co. investment banking firm in New York, described it: Inflation makes people very protective and defensive. . . . Everyone pulls in his horns a little bit and plays things a bit safer."

Jostling around in the middle, between Claude Pepper's retirement-in-come constituents and Herbert Allen's super-rich friends, are the Cassidys, the Smiths and the Pasours, people who are doing a lot of thinking about what is important in their lives.

"It is clear that there has been a fairly widespread view among the public since the early 1970s that the future is not going to be that easy, a sense that things are leveling off, which is different than the 1950s and the 1960s," said Lee Rainwater, a sociology professor at Harvard.

This view, Rainwater claims, leads to a kind of unhealthy pessimism, an alien and dangerous gensation in an energetic consuming society whose values rest on 40 pairs of shoes in a closet or a quarter horse out in the shed.

But there is another side to it out there in the middle, more a sense of reality than pessimism, given expression in a new American debate over values and the issue of what might be called "enoughness."

Jan Cassidy, a divorcee who lives with her two young daughters in Prince George's County, works two jobs to make ends meet. She is angry about inflation, she is upset with her government and she doesn't like the scrimping.

But something has happened. "I have more respect for money as far as learning to control spending habits," she said. "I've learned to look and not buy."

Kevin McLaughlin, a bushy-haired disc jockey in Boise, says he is so strapped for money he can't even take a giggly groupie to lunch. But he has changed, too:

After a divorce 18 months ago, he abandoned the buy-it-on-credit mania that had obsessed his life.

"It was an attitude of 'we're young and free,' that without children we might as well do it now because, if we don't, we never will," he said.

McLaughlin is still paying for that, but his ideas are different. More realistic. "I can't remember the last time I bought new clothes, and going out to dinner -- well, it really is a treat to go to McDonald's."

"We're all greedy. We all want money. It's just a constant circle," he said.

Staff writers and special correspondents of The Washington Post, in recent intervews with heads of families in 10 states and the District of Columbia, heard repeated variations on those themes.

They found inflationary hardship and unhappiness cheek by jowl with wild contradictions -- luxury trips, lusty appetites unabated while creditors rap on the door. But even as they turned up examples of golden success and staying-ahead-of-the-game, they found a nearly universal kind of groping, unstructured questioning and challenging of the old assumptions of enoughness.

Official government statistics, of course, do not measure those intangibles of spirit. But they do reflect the pinch and some of the contradictions. Figures from the Joint Economic Committee of Congress show, for one thing that personal savings are at new lows.

In the third quarter of 1978, 4.1 percent of disposable income went into savings; for the same period this year, it had dropped to 3.6 percent.

Where does the money go? Perhaps into debt payment. Perhaps into the cost of keeping up. Whatever, the savings dropoff is proof of a new and real strain.

And the committee's figures show that Joe Consumer is getting himself deeper in hock -- consumer installment debt has risen steadily during the past three years. In one month of this year alone, consumer credit increased by $2 billion.

But the questioning and the groping go on, as well, although perhaps not apace with the time-honored indicators of economic activity.

Two good examples surfaced in Houston, one offered by Tommy Clayton, an Atlantic Richfield refinery worker who is strapped even with help from his wife's second income, and another by Paul Aless, a comparatively well-off neighbor who teaces Latin at the University of Houston.

The Claytons don't go out on the town as much as they once did. They feel they are losing ground, even with their economizing. They did something else when the enlightment came. They cut out the credit cards -- expelled the plastic temptress.

"We sent all those things back, "Clayton said. "They were putting a lot of extra load on me. I didn't even want the temptation around, because I got myself in a bind with those things before."

The Alessis, with a combined annual income of $37,000, live sparely, indulging only a taste for good wine and gourmet food. But they have an outlook that keeps life in check.

"All of us are to blame for this," Alessi said, putting neighbor Clayton's thoughts in different words. "We are beginning to pay for generational mistakes. We have been told to buy as much as we can, get the biggest car and the biggest house. A lot of it has to do with the postwar boom psychology. We've gotten used to living in a certain way. . . and it's all coming back now to haunt us."

Inflation and that boom psychology have made a very comfortable life for Tony Perez, a Sears appliance salesman in Tampa. He's making money hand over fist, accumulating capital gains, staying out of debt.

But Perez sees something new. "I've noticed more people are paying cash now," he said. "They are not using credit like they used to. They don't want to pay that 18 percent interest."

That is a major change, as Perez sees it. "The younger generation especially doesn't know how to handle money," he said. "They expect to live like thy did with their parents. They're spoiled. We got younger salesmen in here making good money and they're complaining they can't live on it."

Perez couldn't have been talking about Norman Howard, a 32-year-old Air Force veteran who works in industrial relations at a Ford Motor Co. plant near Detroit. Cost-of-living allowances and austerity at home with his wife and three children have kept him solvent, but the attitude is different.

He doesn't buy what he doesn't need, and he avoids the credit card. Howard said he had seen too many friends succumb "to those 10 plastic cards. . . It's you, me, all of us, we are the only ones who can make it happen, but nobody is willing to give up things voluntarily."

Across Detroit, handyman Dean Acheson, 33, teaches college night courses while building a tiny house-restoration business, sometimes bartering his labor for something he, his wife or their 5-year-old son need.

Inflation makes life tight, but it hasn't ruined them -- their restored house in five years has quadrupled in market value to $80,00.

The Acheson attitude reflects their own kind of enlightenment, their own realism. "In American, people seem to believe it's their inalienable right to sit down every day to a huge meal -- and only eat half," Dean Acheson said. "We've got to cut back."

If that sort of realism is a product of the ratcheting pinch of inflation, it would add a bit more force to a thought of Harvard's Rainwater.

"It always intrigues me," he said. "Inflation is presented as an issue on which everybody loses. But what is claear is that there are winners and losers. . . In a period like this, it is probably the very wealthy, those who have stocks and bonds, who have suffered the most. So one could say, 'so what, what difference does it make?' We keep score with money. The value changes and it shifts around."

Few who take a professional interest in it think inflation is a good thing. But some, such as economist Robert Heilbroner, argue that the ready inflation vested pon the United States over past 15 years is merely a natural and revolutionary development in a dynamic capitalistic system, though seldon recognized as such. Rather than treating inflation as an illness of the system, Heilbroner says, we ought to regard it as a by-product of the straining and shifting within the basic framework -- not bad in itself.

There is some evidence, if the Post interview are a guide, that individual capitalists -- the Jan Cassidys, the Tommy Claytons, the Norman Howards -- are intuitively ahead of the politicians and the traditional economists on this score.

In one sense, it is almost as though they are on their own. Left by institutions in an intimate vacuum to fend for themselves. They alternately blame and absolve politicians for their problems. And they don't think the press gives them much help in understanding.

So they begin to tune out, much like Joyce Wilding, 47, a divorced mother of two sons who teaches school in Louisville. She talked about "sensory overload" from newspaper and TV stories on the economy. "I feel that I'm more or less a spectator in terms of the larger economic issues," she said.

"I can't really say I'm angry or that I'm being singled out," said Eriskia Smith, the Air Force sergent in Dulth. "I'm just caught up like everybody else -- It's just something I have to live with."

So they confound the economists, spending when they should be saving cutting back when some hidden theremostats tell them to, making do with last year's automobile, resoling battered shoes, dining on tuna casseroles. Yet they hang tenaciously to the widgets of enoughness they consider most important.

They do so on the strength of a certain logic a sense more practical than philosophical. John Ellis, an engineer for the city of Chicago, father of six children, put it this way:

"Sure I'm troubled by inflation, but I'm an engineer and I tend to look at these things rationally. Frustration, anger, rage -- they're not going to solve my problems."

No one is saying out loud that-the great age of consumerism is at an end or that the acquistive binge is over. That light of dawn has not yet broken over the horizon. But in a nation which sets status and the terms of self-worth by possession, these may be notable distinctions of maturity -- a realization that we've had it too easy for too long.

Sure, the widgets still intrigue us. We're buying those electronic football games and the home video recordings machines as fast as the Japanese can ship them here. But who, after all, ever guaranteed us 40 pairs of shoes in a closet, two cars in a garage, show horses for pets? The real world is something else.