The Sermon on the Mound : THE BROTHERS K <i> By David James Duncan (Doubleday: $22.50; 645 pp.)</i>

So much has been spouted--often piously or pretentiously--about our National Pastime as a sacred devotion that we should not be surprised when a book finally is written that deals with baseball and religion, paired. Baseball and religion are precisely the only two of our institutions that we regularly attach the defining adjective “organized” to. We always refer to Organized Baseball and Organized Religion, but we never say Organized Business or Organized Football or Organized Journalism.

David James Duncan not only understands the twin standing of baseball and religion here in the land, but he also appreciates the subtleties and the cadences of both very well indeed. He doesn’t get gooey about the game or preachy about the worship, and yet I think it’s ultimately fair to say that “The Brothers K” is spiritual.

The title brothers and the rest of the curiously affecting Chance family of Camas, Wash., reside upon a rickety platform held up by the pillars of Mama’s faith in the Seventh Day Adventist Church and by Papa’s might-have-been pitching career. Although the Chance saga covers a great deal of terrain as it lurches and meanders through a couple of decades, Duncan always jerks us back to either the diamond or the church, before, at last, everything runs smack up against Vietnam.

The family is, basically, composed of lunatics, or, anyway, putative lunatics, and even beyond cataloguing the Chances’ extensive hi-jinks, the author has plenty of wacky dissertations for us that come out of the blue. I particularly enjoyed a discussion of King David as a boy and a learned treatise connecting Darwin and slugger Roger Maris in a way that had probably not occurred to you before. Duncan also has a special talent for writing letters and school compositions and showing us, in print, the tick-less sound that an electric clock makes. Duncan is not a man familiar with Organized Restraint.

This makes his Chance family a good bunch for him. There is Mama, the fervent Adventist, and there is Papa, who comes to be better known as Papa Toe, because, after he loses his pitching thumb at the sawmill, his big toe is grafted on as a replacement. Then there are the four brothers: sensitive Irwin; Everett, “the natural ringleader” and “dark cloud”; Peter, who is known as Stanley Einstein, although it could have been Albert Musial; and Kincaid, the youngest and the narrator (although others periodically get their licks in telling the tale). There are, as well, twin sisters, girlfriends, wives, grandchildren with funny names, and what have you.

Papa Toe never grows up; or, anyway, he never grows away from baseball, which is about the same thing. A classic “phenom” until his soupbone was injured (even before he lost his pitching thumb), Papa Toe eventually finds his way back to The Game years later, and he stays, happily, in the minors--”a Triple A kind of guy”--as the boys grow up and get on with their spangled lives.

Mama never seems to come across fully, and that’s a considerable crack in the story. On the other hand, Papa reminded me a great deal of pitcher Jim Bouton, and maybe that is why I took to him so. Bouton left the majors, left baseball, and then, as a hobby, started messing around with a knuckleball, eventually went back into Organized Baseball and finally, around his 40th birthday, got back to the majors--actually won a game. Then he upped and quit. Papa Toe, likewise always in command even if nobody else can tell, does not choose to leave the diamond for good until he uncorks The Worst Pitch In The History Of Baseball as a valedictory.

Mama, meanwhile, devotes her sainted hours to praising the Lord, raising her sons and battling beer, home and away. The Chances are much more reminiscent of one of those goofy inbred Southern families than anything we expect to encounter in such a normal, regular place as the State of Washington.

Unfortunately, paying good attention to “The Brothers K” is difficult. While this is the sort of work where the sum of the parts is greater than the whole, it is also true that the sum of the parts is just too big a sum. No one--most particularly including Duncan’s editor--knows when to say “No, thank you.”

I do not mean to be a wise guy, but there are, for openers, simply too many brothers. I think the Marxes instructed us properly in this for all time when they put Gummo and Zeppo on waivers. Less is less. Other famous brothers that occur to me, namely the Cartwrights, the Karamazovs, the Gestes, the Alous and the Andrews Sisters, all reinforce this conclusion: Three brothers is the maximum.

This fraternal excess is evident in many other respects. Within a very short period, we find four major characters suddenly beset by death, depression, insanity and incarceration, and issues of great consequence in the novel are swamped by minutiae given as much attention. Granted, this is tricky footing for me. Am I being captious? Do I possess a particularly short attention span?

Duncan is a wonderfully engaging writer, and much of his charm is that he is so natural, that he goes with the flow--do we still say free associate ? -- but when things bounce about so frenetically it’s just awfully hard for the reader not to drift along with the story of Mama and Elder Babcock when suddenly we’re supposed to be all tuned in with Peter in India. I do not think it’s any coincidence that the two characters who are most blessed by sections of strong, straight narrative, Papa Toe and Irwin, are easily the two most fetching.

As clever as Duncan is, he just does try you. So you’ve to read him as you watch a baseball game, where there is no clock, and we may go into extra innings, and the fun is to ruminate and speculate and contemplate . . . and second-guess the manager. And suddenly, before you even realize there’s a rally going, we may have to call for the southpaw in the bullpen.