To anyone whose conscience asks why attention must be given to what seems yet another Muhammad Ali con comes a reasonable answer. Simply - and sadly - there is only one more compelling Ali spectacle, his athletic death, the night someone knocks him senseless, and a plodder named Earnie Shavers has a chance to do just that Thursday in Madison Square Garden.

In truth, Ali versus Shavers - or Ali versus somebody who hits harder than Chuck Percy - is about all that allows the champ to attract the multimillion-dollar purses to which he is accustomed, it having been obvious for more than a year that Ali wins any fight that finds him on his feet at the final bell.

Ali's latest show will net him a modest $3 million, with no closed-circuit television and no Yankee Stadium. But there is a possibility the Garden crowd will be several thousand less than the one that watched two pro wrestlers go at each other Monday. And Ali was trying to make us believe he'll dispose of Shavers before the first home-television commercial.

"Attention, attention press," he shouted before entering the ring for three rounds with sparring partner Jimmy Ellis this afternoon. "I'm not gonna change my (overall) prediction, but I might change it to a little earlier. I predicted he'd go in seven, but I might have to get him in one or two.

"He's shown me no respect since he arrived here, no mercy. It can't be over seven, but if it goes over four it'll be exactly seven. But don't be surprised if this isn't another Sonny Liston deal, over in one minute of the first round, 'cause I'm comin' out."

It is possible for a cynic to leave one of Ali's workouts without smiling, but not likely - because, given the general level to athletic humor, the champ often comes across as a roaring wit. Because Shavers has shaved his head for the affair. Ali calls him "the Acorn." And Ali glanced about the crowd at the Felt Forum today and spotted other acorns.

"They're all over the place," he said. "Even Howard Cosell's an acorn, only he's all covered up."

As if on cue, his entourage began chanting. "The acorn must fall, the acorn must fall."

"And the proper place for an acorn to fall," the champion replied, "is the Garden."

Earlier, Shavers had talked about altering his style, from the get-'em-quick charge that weakens near the end if the other fellow fails to fall early, to a more even pace that will allow him to stay with Ali longer than most fans believe possible.

"If he's got to revert to another style," said Ali's trainer, Angelo Dundee, "he's in trouble."

It was about that time that Ali, having gathered every photographer and microphone in the room to him, began speaking to and about his roots, his father, Cassius Marcellus Clay Sr.

"There's never been a fighter like me," said the son.

"Not in a hundred years," said the father.

"Only a hundred years?" said the son, who then added: "You should a seen this man and his daddy years ago, goin' into neighborhoods they weren't supposed to go and getting' off their ice wagon and beatin' up four or five white guys. They're where I got my toughness from, my mean streak."

If his legs have slowed to 33 1/3 (at least), Ali's mouth continues to run at 78. And though he still seems to have a right hand attached to his body, it was largely inactive once again during a session on the heavy bag.

Logic and consistency are two things almost never attracted to Ali and boxing. And sure enough, five minutes after suggesting he would plant the acorn firmly on the canvas quite early. Ali was giving a lecture on rope-a-dope.

"What'll happen," he said, "is that I just might lose the first three rounds, but then he'll be so worn out from punchin' me that he'll be helpless by the seventh. It'll be like bakin' a cake for me. The first few rounds all you'll see is the egg shells and what looks like a mess.

"But when that $3 million's in the bank, and I step in the ring with all them lights and them foxes in the first rows, Oh, Lordy, will I show off. Right now - and maybe the first few rounds - I'll be in my lab, gettin' my cake ready."

It was then Bundini Brown suggested, quite strongly, that Ali stop talking and do some work.

"Hush, nigger," the champ said. "This is my show."

Ali did get with it, though, when the esteemed promoter, John F. Condon, said: "If you don't finish this workout, there won't be any pictures in the paper tomorrow."

When the workout ended, the Garden, which had sued to get Ali to fight Shavers and complained about his lethargic training methods, prepared to admit him into its Hall of Fame, with Condon saying, "If you'll get ready for the official induction," and Ali suddenly shouting:

"Induction into what?"

"The Madison Square Garden Hall of Fame."

"Oh," said Ali. "That should have happened 10 years ago."