Sexton's edge over Jackson getting smaller
Murphy gives his out-half verdict and injury update
Richie Murphy's skills are not just limited to his roles for Ireland as skills and kicking coach.
The former Leinster out-half has been by Joe Schmidt's side for almost as long as the New Zealander has been in Ireland.
It is Murphy's consummate skills as a communicator that stretches to defining the difference between Jonathan Sexton, a world-class out-half, and Paddy Jackson, an international class one.
"Yeah, he's been there, he's seen it all," said Murphy about Sexton.
"He was a Lions winning out-half. He has won three Heineken Cups. He has won a couple of Six Nations.
"That experience is invaluable for a player."
There is not much between the two when it comes to the measurable comparisons uncovered by the blunt instrument that is statistical analysis.
It is the unseen information, unshown to the general public, discovered in the forensic investigation of a Joe Schmidt review that reveals next to all.
"Numbers-wise, they would add up pretty well, but it's the bits in between," said Murphy.
"What makes a really good player? Is it what you see or other areas as well?
"It's probably the case that 'what you see' is very similar.
"It's probably that Paddy is still trying to learn and get better - which he is - at the bits you can't see."
This is the space in which the moment-by-moment, play-by-play decisions are made at blink-of-an-eye speed.
"It's the communication. It's the reading of the game," issued Murphy.
"It's understanding at one particular moment in the game what's the right decision to make.
"And that decision could be based on many different reasons.
"It could be the conditions. It could be the time of the game.
"It could be what one defender is going to do or how he is going to do something differently to another.
"It's very hard to put your finger on exactly what it is.
"But, Johnny's just been in a position where he understands these things probably a little better than Paddy at the moment.
"But, the gap is closing."
Murphy confirmed how Sexton, Rob Kearney, Conor Murray and Andrew Trimble had all completed yesterday's session to be cleared for selection against the brutish French.
There is even validity to the claim Sexton is Schmidt reincarnated on the pitch.
This has come about over time spent working in harmony.
The perfectionist lurking deep within both men unites them in the same single-minded purpose.
Second best is always the worst loss.
"It's a hard one. I think Johnny understands the game through his time that he has spent with Joe.
"In relation to the attack side of the game, he understands how Joe thinks and he understands what plays we put in place for certain reasons.
"But, that is only one part of the game," stated Murphy.
"Once you move outside of the set-piece, maybe the second, third breakdown, after that, it's about general play.
"And it's his ability to read general play is what makes him really good."
The recurring and new injuries that have sullied Sexton's recent seasons have not hampered his game on the rare occasion he has completed one.
All the time, Jackson has been making ground on Sexton, his 25-out-of-26 kicks for Ireland from November on a reflection of how hard the Ulsterman has worked on his goal-kicking.
It is a testament to his mental fortitude that he can come straight back into test match rugby without missing a beat.
"Johnny is in a very comfortable position, within himself," Murphy continued.
"He knows there's pressure on him to get out there and play, but when he's out there, he's very calm, controlled, communicating really well with guys around him.
"He's able to pick the right option at the right time, and that's the key - that's the key to the best out-halves out there."
Murphy pushed how Sexton has "no divine right" to the number ten shirt.
The 'God of rugby' might disagree.