The pragmatic philosopher who first advocated, "If you can't lick 'em, join 'em," was hardly aiming his counsel at the likes of a man who has won 29 of his 30 professional fights, and even now is the world junior middleweight champion.

Yet Tommy Hearns has solidly embraced that advice. He has joined the camp whence came Sugar Ray Leonard, the only man he couldn't beat.

Henceforth, Hearns will be a client of Mike Trainer, the Silver Spring attorney-boxing figure who constructed all those multimillion dollar purses and other emoluments that made Leonard the richest man in boxing history. Trainer had obvious charms for the Hearns people.

Hearns is not bypassing his manager, Emanuel Steward. It was Steward who initiated the arrangement with Trainer, approaching him after a chance encounter in a Syracuse airport and saying, "Mike, we could use your help. Let's talk."

According to Trainer, the talk lasted 15 minutes and "we had an agreement. The same strategy we used to get Sugar Ray everything he deserved, we'll aim to do for Hearns. The right matches, closed circuit, pay TV, foreign rights, deferred tapes, all those things." Plus the endorsements, he added. Trainer merchandises fights.

"There's still money out there," Trainer said, despite the retirement of the charismatic Leonard. He said he was thinking, of course, of a Hearns-Marvin Hagler fight for Hagler's middleweight title.

"Right now, Hagler-Hearns stacks up as a $10 million to $15 million fight, and with the right buildup it could go higher," Trainer said. It could also go toward comforting the unhappy Hagler, who groused last month that he earned only a paltry $1.25 million in his recent title defense against Wilford Scypion.

Boxing's champions are now given to measuring their own take-home pay in terms of the hefty sums Leonard used to earn under the aegis of Trainer. For only three of his bouts, two against Roberto Duran and one with Hearns, Leonard took home a tidy $26 million.

The Hearns people have been nursing a complaint similar to Hagler's. In contrast to the $10 million Leonard was paid in his last defense of his welterweight title, Hearns' pay for winning the junior middleweight title from Wilfred Benitez barely exceeded $1 million.

The Hearns-Trainer linkup was considered an unlikely one in 1981 when Hearns and Steward were firing off a stream of insults impugning Leonard's manhood as their title fight neared. "He's chicken," said Hearns of Leonard. There were other affronts. It was sticky.

"I went to see Steward and point out a few things to him," Trainer said. "I told Steward and Hearns they weren't showing any class and that they should stop the bad language." Trainer said he got a quick and easy agreement and the abusive stuff stopped, "and that's when I first gained respect for Steward."

With the emergence of Leonard, lawyer Trainer became the new fresh face in boxing, the wunderkind of the business. He learned the ropes quickly, took the matchmaking away from the promoters, made his own deals with the networks, exploited closed circuit and pay TV, demanded both guarantees and percentages, made them pay for Leonard's box-office value, set money records and spat in the faces of promoters who wanted options on Leonard's next fights.

He never had a contract with Leonard who, Trainer said, "paid me what he thought I was worth." He still handles Leonard's affairs, appearances, endorsements, his cohost show with Dick Cavett and TV commentaries that still add up to a multimillion a year bracket.

Trainer has already dealt promotor Don King out of Hearns' life, bringing an action against him in the Wayne County Circuit Court in Detroit. King was claiming he held one more option to promote Hearns' next fight, but in the final hours before going to court he decided not to press it.

"We were in a no-lose situation against King," Trainer said. "King's 90-day option on Hearns had long since expired but he was fighting for it anyway. We actually hoped we would lose in court, because King's option promised Hearns a $1 million guarantee against an opponent of Hearns' own choosing. It was a silly option unworthy of even King. Hearns could choose to fight Tom Thumb and collect a cool million from King."

Trainer already has another action pending against King, who claims he has an option on the services of Milton McCrory, another of Steward's fighters. McCrory is scheduled for a rematch with Colin Jones on Aug. 20 for the welterweight title.

King also goofed in spelling out his option on McCrory, said Trainer, who also might have cited the aphorism that "a blundering enemy is one's best friend." King's agreement with McCrory called for another option on him. "Win or lose," his previous fight against Colin Jones. Trainer says King didn't protect himself by providing for a draw, which it was.

Trainer assails "grabbing promoters," who tell fighters they will go nowhere unless they give them options. "They all say they can influence the WBC-WBA ratings. Bob Arum actually wanted seven options on Leonard after he beat Benitez for the welter title in 1979. I told Arum he could have only one, and we named the opponent, David (Boy) Green. After that we were in the clear, out of the option jungle."

Hearns has been idle since December 1982, waiting out King's claim he still had an option on him. "Hearns is a helluva property," said Trainer, the man who took Leonard so far and knows how to exploit boxing properties. His knockout string has earned Hearns the moniker of Hit Man. "Tommy will easily build up to the 160-pound limit, Trainer said. "He'll fight a couple of middleweights early next year and then we'll arrange the big one with Hagler."

Trainer's alliance with Steward is a broader one than merely the merchandising of Hearns. Also in Steward's stable is McCrory, on the verge of being the welter champ, and coming up are all those amateurs in Steward's famous Kronk Gym in Detroit, the same one that graduated Hearns.

Four of Steward's Kronk Gym amateurs are already given solid shots at making the U.S. Olympic team next year, perhaps jogging a Mike Trainer memory that Sugar Ray Leonard came out of that spawning ground. Could there be another one?

For Trainer, with Hearns and McCrory already under his wing, there is much to contemplate. Of a most pleasant nature.