THERE is no scale comprehensive enough to adequately measure the indelible mark Brian O'Driscoll will leave on the Irish landscape when he finally shrugs off the coils of professional sport.
O'Driscoll transcends his sport. For certain, he is a magnificent rugby player, the best Ireland has ever produced and probably the best this island will ever see.
When he rendered three Welsh players impotent with the most spectacular of passes to put Simon Zebo over for his maiden Six Nations try, it was a timely reminder of just how fortunate Ireland have been to have this world star in our midst for so long.
The selflessness of that move speaks volumes for his commitment to the game, a commitment that has not been compromised by the passage of time. The move also, however, led to a moment of sadness and regret for, at 34 years of age, O'Driscoll cannot go on forever.
The build-up to the Six Nations was dominated by O'Driscoll and the controversial way he was replaced as Ireland captain. It hurt him. That much we know from Declan Kidney, the man who made the decision.
Back in December at the draw for the 2015 World Cup, he intimated that this might be his last championship, a suggestion he gave credence to in a television interview that was aired on the eve of Saturday's game against Wales.
So the sadness came when he seemingly ushered in the era of Zebo with one of the greatest passes ever seen on a rugby pitch.
We'll never see O'Driscoll's like again. For sure, he'll never play in the Millennium Stadium as an Ireland player again, but will he be wearing his customary No 13 shirt this time next year when the Welsh visit Dublin?
Excitingly, O'Driscoll effectively tempered the assumption this will be his final Six Nations when he revealed that he hasn't given any measurable thought to retirement, that the decision is one he hasn't made yet.
"If you start thinking that you're going to retire in six months, or that this is my last whatever, then you're already there and you might as well stop then," said O'Driscoll. "I haven't allowed myself to think about it to be truthful. I hadn't intended causing a stir or anything, I answered a question in an interview and that was that.
"I've said all along, I'll listen to my body, I'll go home and talk to my wife to see things from her point of view.
"I'm just looking forward to what great challenges this Six Nations games are. This is game two of five, that's all."
O'Driscoll's comments at the Ireland team base yesterday have led to an almost giddy hope that tales of his probable retirement after the summer's Lions tour to Australia have been greatly exaggerated.
There is no doubt that being a part of what would be his fourth Lions Tour has certain symmetry in regard to his career.
Twelve years ago, O'Driscoll blew across the face of world rugby with the destructive power of a tornado when he announced himself as a world star with an outstanding individual try in the first Test in Brisbane.
Bringing that portion of his career to a close back in Australia would lend itself to a fitting finale for one of the true wonders of rugby's professional era.
"Would I love to be involved in a winning tour?" mused O'Driscoll yesterday. "Absolutely. Unfinished business? I've been very lucky to achieve what I have, particularly in the latter parts of my career with regards to silverware and trophies.
"Would I really love to part of a winning Test series? Absolutely. Would I like to tour and not win a series? Not really."
It is sobering to realise that there have been only four series wins for the Lions.
They won in New Zealand in 1971, in South Africa in 1974 and 1997 and in Australia in 1989.
O'Driscoll has toured three times – although his 2005 Tour when captain was cruelly ended by the spear-tackle – and a series win is something he covets.
"It's impossible with the amount of conversation, the amount that's written, the amount that's spoken about the Lions not to get caught up in it, but not to let your mind wander here and there.
"But I understand too, that the Six Nations is a means to that end. If you can get this bit right then you give yourself more of a chance of being involved in something in the summer," he said.
The Ireland centre readily admits that failure to win a Lions series so far is one of very few regrets in his career – "I didn't win a World Cup, but I'm not going to win one of them, so that's two unticked boxes" – but he isn't getting hung up about them.
"I've been pretty comfortable in myself for a few years now. I don't really think about those things until those questions are posed of you. Listen, I'm easy-going, I'm pretty happy in my life outside of rugby but I still love what I do.
"I enjoy going in every day, I love going out on pitch, I love the laughs you have with the boys. But I do realise that's just one component to my life and there's other more important things than your profession."
O'Driscoll is undeniably the doyen of the Ireland rugby team. He is helping usher in the new generation while still providing the individual thrust of his brilliance when the occasion calls for it. He is clearly revelling in the youthful exuberance of Simon Zebo and his ilk.
He doesn't see much of himself at 23 years of age in Zebo, though!
"I'm certainly not like Zeebs – he is one of a kind. But that's great. I think he brings a great energy and a freshness. He and Craig (Gilroy) are dealing with it in their own way. That's what works for them."
And they'll make mistakes and suffer setbacks along the way. That's the nature of life and professional sport. It's an experience O'Driscoll wouldn't deprive them off. Neither would he avoid any of the traps he himself fell for.
"I wouldn't say anything to the 23-year-old me now," he revealed.
"You have to make mistakes along the way to appreciate when you get it right the next time. That's what life is all about.
"Without getting too philosophical, I think in your rugby life and your outside life you have to make those errors and say 'that's not me at all'.
"You have to find out what sort of person you are and what sort of player you are.
"I would say, 'live it exactly the same way as you have done and enjoy it as much as possible', because there are great days.
"It's a lot of fun. It's nerve-wracking but it's lot of fun, pulling on a green jersey and a lot of pride to be taken out of it, so really treasure those days because in two, three, five years, 10 years you'll forget what that feeling's like, so enjoy it while you can."