All I can tell you for sure, is that he was the best in the world in his own day, by a very substantial margin.
Yeah, he was once the best in the world - like 130 (or so) years ago! But what did it take to be the best that far back? We simply don't know.
I would guess that at the very least, it took being a specialist in boxing, as opposed to another combat sport. Obviously we have to call it based on what little we know.
Because he was homeless and it was an MMA trainer that stumbled upon his talent.... If legend is to be believed.
Perhaps he is in the wrong sport then? You could argue that switching from Queensbury to LPR boxing, as many fighters did in Sullivan's day, was like shifting from MMA to boxing. Either way, are we going to speculate who good a boxer he would have been, if he had taken a different path?
But that's just it, we know next to nothing about Sullivan. But you just take it for granted, that he would beat a MUCH bigger, stronger modern athlete... who, for all we know, could be a better BOXER than John L. ever was.
I am not taking anything for granted, but we have to work with what we have got. In the absence of any better evidence, it is probably fair to pick the dominant boxer of era A, over somebody who was never a world class boxer in era B. Do you have any better suggestions?
"Almost certainly" sounds pretty much as granted as it can be. Yes, it would be fair to pick a top boxer from one era over a non-top boxer from another era... provided the two eras are even remotely comparable. And I can't see, how anyone can honestly think the 1880's can be compared with today.
That 130 years ago the talent pool was but a very small fraction of what it is today. That gloved boxing was a fairly new thing, and not yet "evolved". That most boxers in the earliest films we can study today look very primitive.
Working out the size of the global talent pool is a minefield. There is strong evidence that it was bigger than it is today, in the years just before the first world war. There is circumstantial evidence that you had a very large talent pool in the early 1800s, but the sport would have to be seen as being in a state of transition when Sullivan arrived on the scene. Make of all this what you will. It cannot be denied that gloved boxing was a very recent development, though you can make the argument that the key methodology of gloved boxing, actually developed late in the bare knuckle era. The word "primitive" might not be appropriate here. They might simply reflect the rule set of the era.
For the entire 1880's decade, BoxRec has registered a total of 4.638 pro fights. For the year 2016 alone, 26.873 fights can be found in their database (as of April 9, this year). Are you really gonna argue, that 130 years ago there may have been as many active boxers, as there are today?
Yes, absolutely. Boxrec is just a record of what historians of the last few years have been able to find, by looking at old newspaper cuttings. No historian imagines that it is a complete record, or anything close to a complete record for the 1880s. Obviously if a fight takes place tomorrow, it will be on Boxrec the same evening.
Good point. Cro Cop was a converted boxer and even in his 40's he managed to give Jarrell Miller a licking. Miller actually did better with his knees in their K1 fight and Cro Cop the kickboxer had better hands.
I'd say it's possible; there are probably thousands to fighters and their fights from the 1800's that are lost to time. That said, the overall standard of modern boxing is higher. Some of the greats from the early eras look like stiffs to the modern eye.