What quality distinguishes ATGs?

Our perceptions.
Who is or is not an ATG is subjective.
For example, I've seen Floyd Patterson called an ATG on this board. I completely disagree, but for those who believe it, he's an ATG

 

Just off the top of my head, chronologically:

Fitzsimmons
Jeffries
Johnson
Dempsey
Tunney
Louis
Marciano
Liston (maybe)
Ali
Holmes
Tyson (maybe)

A lot of people will disagree with some of these. That's kind of my point.

 

Showmanship.

 

Quality. There are as many types of fighters as there are types of birds, and they're all good for different reasons. To be an ATG, you need to be quality.

 

It is hard to find a common factor.

What might give us a clue is the number of fighters who have the talent on paper to be great but never make it.

They all have a certain level of consistency, which sets them apart from the nearly weres. I don’t think there is any all time great who you could really say was inconsistent.

They all have a certain completeness. That is not to say that they didn’t lack elements because they all lacked something. They were all a very complete package in terms of their particular style i.e. boxer, swarmer, slugger, boxer puncher.

 

Had a family friend, contemporary of my father's, in my youth who was a big boxing buff.

He would say of this fighter or that: "He has a lot of champion in him."

To me that is the indefinable quality.

 

"It's great to want to be great"
- Larry Merchant

Ego. Maniacal preparation. Physical/Mental aspects. Hunger. Determination. Desperation.

 

You can't be an all-time great if you're a technically incompetent bumsteak like Dempsey. :deal

 

....

Hes written the best book on boxing/punching technique

 

^^^

 

it's different for different fighters. sam langford was an atg because he never ducked anyone and was undersized in most fights, plus he could punch. benny leonard was an atg because of his skill level and who he beat in his title reign. dempsey gets so much crap on these boards but he was an atg, no question. he took the sport to a place it had never been before.

 

I agree with all of that plus heart. Fighters like Holyfield who have shown heart in spades fit the definition of all time great. Heart plus the quality that you mentioned so Robinson, Hagler, Leonard, etc all qualify.

It's very subjective, though, because someone can be a cracking fighter but not necessarily great. For example Nigel Benn. Was he an all time great or not? Some will say yes, others no.