I think AJ Liebling coined the phrase "The Sweet Science", or at least popularized it. He had a book by that title.
I think its apparent why boxing is given such a name. The boxing ring is the lab and the match is the experiment. All kinds of variables. What type of style does each fighter have? Who is younger? Who wants it more? Etc. But still, boxing is unpredictable. Fighters adapt. Survival of the fittest, etc. Sweet has multiple meanings. One is ironic. At times, boxing is anything but sweet. When your fighter wins and gets his formulas working correctly, really there is nothing sweeter than your favorite fighter beating his opposition.
Take last week. Mayweather vs. Gatti. Mayweather was the skilled technician. Gatti was the rough heavyhitter. This wasn't a street fight, with no skill involved. This was boxing, which requires technique. Mayweather was the sweetest Scientist. For me, it was great. One of my favorite fighters beat one of my most hated fighters. Dominated. Both physically and mentally, Mayweather imposed his will over Gatti. And that was one of the best displays of Sweet Science seen in recent years.