There's no anticipation in sports like that before a fight between famous boxers who have never met. Nothing would seem to be simpler than visualizing how two fully scrutinized veterans will react to each other in a ring. In fact, nothing in sports is so unforeseeable.

That's why the welterweight championship fight between Ray Leonard and Thomas Hearns here Wednesday (10:30 p.m. EDT, no network or cable television) will be the richest sports event in history, with net profits expected in the $25 million neighborhood.

The reason that Leonard can figure on a $10-12 million payday ($8 million guaranteed) and Hearns more than $5 million for one hour of work is that nobody, but nobody, knows what is going to happen when the WBC champion "Sugarman" (30-1, 21 knockouts) meets the WBA champ "Hit Man" (32-0, 30 knockouts). The official line reflects that: 6-5 pick 'em.

Seldom have so many basic questions about a fight been so completely moot on the eve of the showdown. Interestingly, one of the new such boxing bonanzas came just a year ago -- Leonard versus Duran I.

Such great mystery fights need a known and respected champion against a flamboyant but less-than-completely-proven phenom. For the Brawl in Montreal, Duran was the blue chip commodity, while Leonard had the flash but lacked a victory over a legend.

In the last 25 years, few if any nonheavyweight fights offered the richness of debate over the tactics and relative basic worth of Leonard-Duran. That's why it grossed nearly $25 million, second only to last fall's Larry Holmes-Muhammad Ali heavyweight title fight, which grossed $30 million.

Now, Leonard versus Hearns promises even more dazzling contrasts than Leonard versus Duran and asks more provocative questions.

Is Leonard one of the all-time boxing greats, dominating a strong welterweight era, including Duran, Wilfred Benitez and, now, Hearns?

Or did Leonard barely edge Benitez, then get revenge for his only loss with a victory over a fat, over-the-hill Duran? Has Leonard been as lucky as good?

How can Leonard, at 5 feet 10 with a 74-inch reach, handle a man of 6-2 1/2 whose 78-inch reach is longer than either Joe Louis or Jack Dempsey's?

Is Hearns, just one day hence, going to look like the guy who could become the first four-division champion in history?

"This fight could put me in the Hall of Fame . . . like, ever. This is a chance to show that I'm the best fighter who ever lived. I might be champion right on up through light heavyweight," said Hearns, getting carried away in front of his No. 1 enemy -- a microphone. "Well, anyway, it'll make me the top welterweight in the world," he quickly amended, realizing that he'd just kayoed the next several years of his career in one sentence.

Or, on the other hand, is Hearns, as Leonard insists, just an unpolished, untested 22-year-old with a big punch and a world of flaws waiting to be exposed? After all, Hearns has trouble with a jump rope and a speed bag. Will Leonard make him look like a man in a revolving door?

Can Hearns go 15 strong rounds? Can he handle an inside fighter as tough as Leonard proved himself to be against Duran?

In fact, is Hearns, whose only Grade-A win came last year over Pipino Cuevas in two rounds, really an outstanding fighter or just a heartstopping aberration of physique?

Only in boxing could such fascinating and fundamental questions remain open to sane debate in the shadow of the biggest day on the sport's calendar.

In such circumstances, it is the central task of each boxer, and his pug think tank, to sift through all the ponderables and, by an act of imagination, "see" the fight as it will truly happen. The man who sees the fight correctly, then builds a plan to match that precognition, usually wins.

The Hearns scenario is extremely simple. The Motor City Cobra will fight as he always fights: long, hard jab, octopus defense of arms and elbows, not too much footwork, and a patient wait to land the meanest right hand-- pound for pound -- on earth.

Asked what he thinks are Leonard's weaknesses, Hearns answers, astonishingly, "Basically, I don't know. I just prepare to fight my way, then I figure out the other guy's openings as the fight goes along."

Manager and guru Emanuel Steward says, "I don't even consider the other guy's abilities. Thomas does the dictating. Hell, Leonard was intimidated and scared by Duran. What's he gonna think when he discovers he can't get inside against my big, strong man? I see no future for Leonard. He'll retire after this fight, a broken man. He'll even lose his (TV) commercial . . . He can't clinch Hearns like he clinched Duran. When you get hurt by a big man, the only thing you can tie up is his knees."

What should Leonard be practicing?

"Clotting," said Steward.

The Hearns way is the Kronk way -- the method he learned in the tiny Kronk gym in Detroit where the temperature stays above 90 degrees -- and the proper Steward technique for anything is the one that causes the maximum pain in the minimum time. Cruelty and simplicity are the twin codes.

Anyone looking for a synthesis of all the ideas flying around this fight has to go to the Leonard side. That's where the midnight oil has been burning.

In the last hours before a fight, hints sometimes become heralds of history.

From Leonard's mouth, and from his entourage, new and strange sounds are coming.

"For the first time, I've had visions of a fight at bedtime," claimed Leonard.

"Hearns is so programmed that I see what he'll do. I see myself putting all the fundamentals of boxing on display. I will dictate the pace. And it might not last long," said Leonard.

"I've had this dream, this vision, for nearly two months. It has to happen. I have no concerns about Thomas Hearns," he rhymed, and then dropped into a less oratorical voice, adding, "Notice how people never give me credit when I win? Like talking about Duran's 'cramps.' I get tired of that. I'm fighting this one for me."

Never before has Leonard, or his camp, seemed so anxious -- almost greedy -- for the first bell to ring.

"My guy's liable to hit this guy on the chin real early," said Angelo Dundee, Leonard's manager. "Hearns gets hit solid, too, 'cause he's off-balance and flat-footed when he misses (a punch). We think Hearns can be hit hard and often."

What have we here? Self-hypnosis? Collective delusion? Or just some deliberately misleading prefight smoke?

Says a man in the Leonard camp: "I think they're serious about going after Hearns in a hurry. I see Ray and Angelo and Janks (Morton) watching films and they get all excited when they see Hearns' defense."

"I've watched Hearns' films and he always starts with the same feint," Leonard said, imitating a whole series of Hearns gestures. "If he'll just accommodate me and do it one more time, I'll throw a left hook that could end the fight."

Even putting aside this daydream Sunday punch, it seems that the same self-assured Leonard who decided, against all advice, to brawl with brawler Duran in Montreal, now may have decided, with all advice, to slug it out with slugger Hearns.

Leonard believes that Hearns' indisputable power is only dangerous at long range, while, on the inside, the balance of power, experience and technique is all with him. Get inside the walls, then start setting the dynamite.

"Everybody says if I win, it'll be a decision," said Leonard. "Maybe so. I can fight a lot of different ways, any way I have to. But I don't think it'll go 10, at the max."

The strangest of all conceivable strategies against Hearns would appear to be: attack him and tear him apart.

Yet Sugar Ray Leonard, determined to prove that the best of him has neither been fully seen nor properly appreciated, may well have decided that this is the path to glory.

Or unconsciousness.