''Fundamentally,'' Barzun said in an interview last week, ''things haven't changed. Baseball still reflects our society, it's just that our society has changed.''
Baseball, Barzun says, once expressed the unification of America, the teamwork involved. ''When we look at the triumphs of American technology on a large scale,'' he says, ''we see the fine workings of a national machinery - everybody in every department cooperating effectively with no gaps in time.
''It was like the making of a double play perhaps. Or a relay in which nine men speedily clicked together to achieve a desired result. It's a beautiful thing to observe.
''But now, the contentions in baseball parallel the enormous unrest in our society - there's more litigation, for example, than ever before. And the star system has gotten out of hand. The teamwork that once marked the beauty of baseball is now scorned, and along with the diminishing appreciation for the rich qualities of baseball, there has developed diminished appreciation for the rich qualities of American life.'' A Dimension of Summer
But a summer without baseball would not be quite the same for Barzun - who is still a casual fan - or for Jake Rabinowitz, proprietor of A & J Grocery on Second Avenue, who said, ''I wouldn't have all the aggravation watching the Mets and Yankees, especially this season, but sometimes they give me pleasure - once in a while they win.''
For Roger Angell, a writer for The New Yorker magazine, baseball would be missed. ''It's part of my summer habits - and maybe my winter habits, too,'' he said. ''I suppose I'd get along all right without it, but I'd rather not. There is a continuity with baseball -and there'd be a feeling of loss with it, like, there goes something else in our lives.''
One of the qualities that Angell likes