No, the fight did not set boxing back 25 years. Fifteen, maybe. A rusty George Foreman overpowered Ron Lyle in a carnival of knockdowns last Saturday in Las Vegas, and if the cause of scientific boxing was not advanced, a good time was had by all. Foreman had wanted to show that, despite his loss to Ali in Zaire, he could take a punch. He took them by the dozens. A couple of them sent him down twice, and one sliced a three-stitcher inside his lip. But at the end of Round 5, sagging but still slugging, Foreman finally stepped back to let Lyle fall unconscious. So much for the first big one in George's comeback. "Lord," he said, "now I've paid my dues."