Art or science? Statistical heaven or a window on the warrior soul? Rugby union can be all these things but a glance out of the window yesterday at the leaden skies of south-west London was to be reminded, above all else, of its constant diversity. How can you compare Bloemfontein in June with Twickenham in December?
The answer is "not easily", which is why 75,000 people will turn up today unsure about how England will fare against South Africa, if not about the wisdom of taking a raincoat.
Crouched over his computer screen in Cardiff, though, is a man who thinks he knows how this afternoon's contest will unfold. The head of the new International Rugby Board game analysis centre, a former referee called Corris Thomas, has been studying England and South Africa closer than most over the past few years and, wet pitch or not, gently advises those awaiting buckets of tries to stick on their "Best of . . ." videos instead.
Thomas will remind you, for example, that England have scored just two tries against their top-ranked rivals all year, while South Africa, apart from one blip against the All Blacks in Johannesburg in August when they ran in six, have otherwise scratched just one five-pointer from their five other biggest games in 2000.
It is always easy to dismiss less than cosy statistics, particularly those which fail to take into account whether a side wins or loses. Clive Woodward was at it again yesterday: "International rugby is about winning" - but the fact remains his side have not scored two or more tries in the same game since their Roman gallop against Italy last March.
Particularly critical to England are the men known, in modern parlance, as the "back three". On the Wallabies' recent tour, all their points in three Tests came from Matthew Burke, Joe Roff or Chris Latham, and 13 of England's 23 tries this year have come from the same area.
So why are Austin Healey and Balshaw, the squad's most elusive runners, starting on the bench? Even some loyal voices within the coaching team privately argue it is no use creating holes if the men best equipped to exploit them are sitting in the stands.
"The reason we haven't scored as many tries recently - and don't forget during the Six Nations they went berserk - is that we haven't finished off the chances we've created," is England backs coach Brian Ashton's verdict. "We opened up Australia two or three times and didn't finish them off."
This time around, England may line up fractionally deeper because of the underfoot conditions.
Today's match will not be a test of England's off the cuff attacking instincts but, one day soon, they will be required to disprove the nagging evidence hidden in those Cardiff computer files.
ENGLAND: M Perry; B Cohen, M Tindall, M Catt, D Luger; J Wilkinson, M Dawson; J Leonard, P Greening, J White, M Johnson (capt), D Grewcock, R Hill, N Back, L Dallaglio. Replacements: M Regan, D Flatman, P Vickery, M Corry, K Bracken, W Greenwood, I Balshaw.
SOUTH AFRICA: Fleck, J Mulder, S Terblanche; B van Straaten, J van der Westhuizen; R Kempson, J Smit, W Meyer, A van den Berg, M Andrews, C Krige, A Venter, A Vos (capt). Replacements: C Marais, O le Roux, W Brosnihan, AJ Venter, D van Zyl, G Esterhuizen, C Williams.
Referee: David McHugh (Ireland).
