One aid to contentment is the ability to foregive life for being the way it is. The person who carries the proverbial grudge against the world lacks that valuable knack.

Starting Sunday night here at the All-Star Game, baseball fans will find out if they can discover it in their hearts to forgive baseball for being itself.

Perhaps the most frequent pat comment about the impact of his summer's strike is that an illusion was shattered, or a fantasy was destroyed.

From the taxi driver's tongue to the haughtiest editorial page, the same cliched assumption has flourished: that baseball's health is directly world of escape, and if that umbilical relation is severed, the game will wither.

Do baseball fans really come to their game in search of a trivialized alternative to daily experience? Or, more likely, do they inevitably find within the ballpark world a living theater where all the familiar, yet ambiguous, forces of life are at work?

The initial lure of baseball is certainly the simple heroism of a nineth-inning home run or the grace of a leaping catch above the fence.

However, baseball is sustained not by the occasional visitor who sees one game a season, as he might attend the circus, but by the hardball ecidivist who can't keep himself from coming back.

"When I was in Baltimore, we did a study which showed that almost all of our attendance, year after year, came from the same 100,000 people out of a city of two million," said Frank Cashen, then Oriole general manager, now the Mets' boss.

The reason that true fans, the hard-core 5 percenters, are permanently hooked probably has a lot more to do with their taste for reality than their desire for illusion.

The lifetime fan, the spine of the game's support, looks at the characters in his favorite pastoral passion play with an almost frightening throughness of knowledge. With the possible exception of presidential candidates, it is possible that no group of Americans is scrutinized so constantly and thoroughly as baseball players. Entertainers have their sensationalized tabloid press, but scandal is not synonymous with depth. Other athletes are put under the microscope, but none of them have the media mastication afforded by a 162-game eight-month season.

Perverse as it sounds, we may know more about many players -- their fears, traumas, hopes -- and we may have seen their reactions in more moments of genuine stress, then many a cousin or uncle in our own familes.

At least in the current age, we seem attracted by the excellence of athletes not so much because their deeds seem part of a fairy tale, but precisely because we know all the arduous human parameters of their achievement. Sit in the bleachers and you will hear far more speculation about injuries and age, about the mysteries of lost confidence or the ability to respond to pressure, than you will hear vacuous idolatry of muscles.

Perhaps that is just the temper of the times. But it's the case at present.

Will fans who want to see their flawed heroes whole be permanently put off by seeing the business machinations of their sport in equal fullness?

Isn't as likely that the strike of 1981, whether we consciously realize it or not, will simply become another part of lore, another exploration of the character, or lack of it, in the players and owners who are the major protagonists of the game?

As a group, baseball's players have shown as much about themselves in the last two months as in any June and July in the sport's history.

This summer's strike was, in part, a test of the players' ability to grasp a slippery moral principle. As a group, major leaguers had more to lose than gain in any strike. After all, in the last five years of free agentry, the majority of current players had their big shot at the pot of gold, and now have time to collect the cash that must bolster them for a lifetime; they knew that the strike issues would have more impact on future players than themselves.

The owners assumed that, if self-interest ruled, the union would become progressively weaker and, finally, capitulate on direct compensation. It didn't.

That the players association could stand almost 99 percent firm on an issue that was, for many players, more a matter of principle than principal, was a shock to owners, who learned to respect their employes more as strikers than as athletes.

"It's strange, but both sides seem to look at the other with more respect than we did before," said Yanbee owner George Steinbrenner.

Now it is baseball's fans who have a decision to make.

Will they see their game as a fairy tale industry that has unspecified "responsibilities" to its fans?

If so, then, in outrage, they will cry for fan boycotts and the like. One Washington bartender has already arrived here with 10,000 whistles to distribute to the crowd so they can "blow the whistle on the players and owners."

Or will fans, after their initial anger, accept baseball for what, beneath the skin, it has always been: an uneasy marriage of business and sport?

Almost surely, baseball will regain its vigorous health, so long as the product on the field is undamaged and undiluted. That's why gimmicks like the current split season are potentially more pernicious than the strike itself.

To be sure, plenty of fans have felt a genuine sense of loss this summer; for them, the ballpark may never seem the same, now that they suddenly believe that their enclave is no longer safe from the world beyond the outfield fence. That's a shame, and nothing's to be done about it. It's a dead loss.

However, what binds the vast majority of spectators to baseball is its validity as absolutely realistic theater life and entertainment is far thinner than the paper of a million-dollar contract.

For those of us who view the game that way, there is no reason to watch Sunday's All-Star Game, or the rest of the season, with any particular jaundice. Baseball always appealed to us despite its patina of illusion rather than because of it.