In the meticulously planned career of Joe Calzaghe that is expected to reach a perfectly orchestrated climax at Madison Square Garden here tomorrow, only one possibility has been left to chance.
However, it is a detail that can change any fighter's life. It concerns the ability of Roy Jones Jnr to renovate at least some of the talent that once made him the shooting star of the ring.
Anarchic – he was once arrested for carrying a gun through an airport – and often misunderstood away from his bailiwick of America's southern states, he had mesmerising speed and punch selection that sometimes seemed to come from another fighting planet.
They were filled with a mad certainty, those punches of the man from the Florida back country and they made nonsense of the orthodoxies of the ring.
He threw punches from no known textbook but his own wild and destructive imagination, disabling blows beyond the resources of the most concentrated defence.
At 39 that lightning cannot be reproduced and he concedes it is so with a nod and a sigh. "Hey," he says, "the years take from everybody, but sometimes, when it matters enough, you can find that a little something is left. I'm not making any big claims right now, but maybe you all, including Joe, should not forget that. I want this fight very badly, I want to show I'm still Roy Jones Jnr. No one should ever forget what Roy Jones Jnr can do."
Those who have been around Jones from the days before he seemed to lose a self-belief that, as he strutted and posed, often brought glassy-eyed terror to his opponents prior to the first bell, say that when he speaks in the third person it is a sign that he feels that once more he can produce some of that old intimidating aura.
If Calzaghe was 26 rather than 36, if it was not true that in his long and acclaimed career of 45 wins without defeat he has never been in with an opponent remotely of such pure punching ability, the apparent revival of Jones's spirit here might not carry the substantial hint of menace that it does.
It is certainly not diminished by the belief of Bernard Hopkins, beaten on a split decision by Calzaghe in Las Vegas in the spring, that the Welshman is made for Jones. Nor is Hopkins any old witness. Back in 1993, when Hopkins was considered the best pound-for-pound fighter in the world, he was not just beaten but outclassed by Jones. A few months ago in Las Vegas Hopkins knocked down Calzaghe in the first round. Disturbingly for those who see Calzaghe-Jones as the present versus the past, Hopkins is 43.
Even at this advanced age, Hopkins' own ambitions certainly remain alive after his defeat of the previously unbeaten warrior Ohioan Kelly Pavlik last month in the wake of the Calzaghe loss. The manner of his defeat by Jones, a decade and a half on, still gnaws at a proud man who believed that, in a shuffling, time-expired way, he deserved a decision over Calzaghe.
Hopkins thinks that the remnants of Jones, the last of his speed of hand and mind, can ambush the Welshman tomorrow night. He says: "Joe will suit Jones. He will not have to worry about finding him. That's when Roy's at his best, picking his counter punches."
Yet of course it is not quite so simple. Jones, grey-bearded and, his people say, more serene than at any time since those days when he swaggered into the ring as though it was his most natural habitat, certainly lost something down the years.
The theory of one boxing insider here is that the terrible consequences of his compatriot Gerald McClellan's defeat by Nigel Benn in London in 1995 may have had a deep effect. Jones was breezing through his boxing and his life then, and this week he recalled the mood of those days when he said, "I was having a good time. I was beautiful. I was more than just a fighter. I was able to make it so delightful."
Delightful in the freedom it gave him to pursue anything that pleased him. He was like one of his prized falcons. No one could touch him. He could fly beyond any challenge, any restraint. Then he saw the formidable puncher McClellan, a man with a ferocious appetite for his version of the good life, whether it was fast women or venomous fighting dogs, cast into a wheelchair and darkness after a brain operation in a London hospital.
Jones is unwilling to go into such dark areas. He prefers to say that he has been inspired both by the presidential victory of his hero Barack Obama and the stirrings within himself of an old confidence.
"Joe Calzaghe is a great fighter," says Jones, "and I'm proud to go into the ring with him, but I'm also proud of what I have done in the past and what I believe I can do in the future. If Joe thinks he's dealing with a washed-up fighter he's making a serious mistake."
Jones's claim is that so many of the old distractions have gone under the pressure of his need to win here. When he suffered crushing defeats by Antonio Tarver and Glen Johnson, knockouts in the second and ninth rounds respectively in 2004, it was as though the best of him had drained away. The blows came less than a year after he had danced to historic victory over WBA world heavyweight champion John Ruiz and then, on a split decision, beaten Tarver for the WBC and IBO light-heavyweight title. Those were victories which persuaded him again that he could be a master of any situation.
For the Calzaghe camp the imperative is to believe that when Tarver and Johnson separated Jones from that certainty four years ago, they inflicted wounds that would never truly go, certainly not with the slender healing power of a victory over the shot-through fellow time-traveller Felix Trinidad.
This week Jones was asked how he compared himself today with the best of his past. "I don't know, I can't say, but that's not for me to decide. When I put my skills on display at the Garden it will be the time for you all to decide."
Joe Calzaghe can only hope that he is dealing with no more than the ghost of a sensational past. Anything more than that, and he will know that he is involved in the most hazardous fight of his unbeaten life.
Keeping up with the Jones
Roy Levesta Jones Junior
Born: 16 January, 1969, Pensacola, Florida
Height: 5ft 11inReach 74in
Record: 56 fights, 52 wins (38 by knockout)
* Won silver in the light-middleweight division at the 1988 Olympics in Seoul.
* Named 'Fighter of the Decade' in the Nineties by the Boxing Writers' Association of America.
* In March 2003 Jones beat John Ruiz to become the first former middleweight title holder to win a heavyweight title in 106 years
* Jones has released two rap albums, one as a solo artist in 2002 and one with his group – Body Head Bangerz – two years later.