Christ And The Adulteress (1508-10) Titian

Kelvingrove Art Gallery and Museum, Glasgow

Absurd comparisons can be telling. Try this. "He had just come to the bridge; and not looking where he was going, he tripped over something, and the fir-cone jerked out of his paw into the river.

"'Bother,' said Pooh, as it floated under the bridge, and he went to get another fir-cone. But then he thought he would just look at the river instead, because it was a peaceful sort of day, so he lay down and looked at it, and it slipped away beneath him... and suddenly there was his fir-cone slipping away too.

"'That's funny,' said Pooh. 'I dropped it on the other side'."

This is the origin of Poohsticks. (Sticks soon replace fir-cones.) It's strange that this elemental game should have been created only in the early 20th century. It's not so strange that Pooh's revelation should hold various basic lessons about the mind and the world.

For example, played as a competitive race between two dropped sticks Poohsticks demonstrates the power of delay. You could play the game without a bridge, with only a stream and a marked finish line, and it would work just as well. But the sticks would stay in view all through – and without the element of vanishing, the interval of invisibility, there would be no tension, no waiting, no surprise result.

Played with a solo stick it's equally enlightening. It teaches the continuousness of things, how something that has disappeared can reappear elsewhere. But it also teaches the discontinuousness of things. Something that's expected to appear may not appear when or where it's expected. However much you might try to gauge the speed and direction of your Poohstick, you will fail. It always arrives out of nowhere.

It shouldn't be surprising that Poohsticks has analogies with pictures either. It's a very visual game. It involves things vanishing and appearing, things going behind something else and emerging again. Pictures are made up of things overlapping other things. They're a tissue of hidings and showings. And occasionally something emerges from behind something else with no cue or apparent connection. The "out of nowhere" effect is one of painting's tricks.

The work on this page, Christ and the Adulteress, is a sumptuous Venetian painting with a changeable history. It was once credited to Giorgione. Now it is normally thought to be by Titian. The subject has been disputed too. It looks like Christ and the adulteress, though a few have seen Daniel and Susannah. But, most seriously, the painting has been literally carved up.

A copy by another artist shows what, roughly, it originally looked like. A narrow strip has been cut off across the bottom. More drastically, the whole figure of a standing soldier has been removed from the right side – you can still see the tip of his knee, in blue and white hose, just poking in. Most of this soldier remains lost, but a section with his head and shoulders has turned up, and is in Kelvingrove too. Fortunately no slices have been taken from the top.

The scene, Christian-Venetian, has divided loyalties. It has its figurative drama, a relay of turns and gestures, telling a story of accusation and repentance, rebuke and forgiveness. It is also a surface of rich material delights, a quilting of colours and textures, folds and gleams, whose pleasures seem indifferent to subject matter. The accusing man is just as gorgeously clothed as the accused woman, and Jesus himself hardly less.

But it is one small detail that becomes the emotional and sensational high point of the painting. It isn't directly a part of this human business. It's the background. The only bit of background that – as it stands – the picture has. (The surviving section of the soldier shows that in the original there was also a distant glimpse of the sea at the very right side.) In other words, it's that green grassy knoll, with trees and sheep, that appears above the woman's head.

It appears out of nowhere. We can suppose that somehow this mound of ground is continuous with the green grass verge of the foreground. But there is no visible path between them, nor are the two divided areas near enough to establish a smooth pick-up between them. This foreground disappears behind the group of figures, and so conclusively that when it reappears at the top of the picture, behind their heads, you aren't expecting it. There is a visual delay. It vanishes. It suddenly emerges. Poohsticks.

Other factors intensify this knoll. It provides the picture's maximum contrast between light and shade: the dark edges of building and cap against its bright green. It shows a little idyll of sheep, which have all kinds of significance in Christian parables and classical pastoral. It is a pillow of softness, on which the woman, leaning inward and slightly backwards, seems to be laying her head – a gesture that goes with the rather somnambulistic action of the whole scene, and seems to give her a blessing. But it's the pause, the interval, the effect of delay and sudden appearance, that gives this detail its piercing force.

About the artist

Titian (1485-c1576) recently made a surprising appearance in British politics. The issue came down to how long he had lived. We don't know, is the answer. But in his long life he discovered the full powers of oil painting, using it with unprecedented sumptuousness, tenderness, sexiness – and unprecedented roughness and bleakness. He turned his hand to religious ecstasy and pagan orgies, pampered nudes and meditative portraits, and in old age developed the first "late style" in European art – free and unfinished-looking, barely articulate, "painted more with his fingers than his brushes", as contemporaries said, made of "broad and bold strokes and smudges, so that from nearby nothing can be seen". Perhaps Mr Brown would say the same.