The image of Uncle Tishlin bore a distant expression for a moment, then said, ‘Apparently that’s part of the beauty of it; just because the Sleeper Service is another oddball doesn’t mean that it’s any more likely than any other GSV to have the Grey Area aboard; the GCU will have to lie off, and that’ll make this Mimage-stealing trick easier. If the Grey Area was actually inside the GSV at the time it probably couldn’t carry it off undetected.’

Genar-Hofoen was looking thoughtful again. ‘This artifact thing,’ he said. ‘Could almost be a what-do-you-call it, couldn’t it? An Outside Context Paradox.’

‘Problem,’ Tishlin said. ‘Outside Context Problem.’

‘Hmm. Yes. One of those. Almost.’

An Outside Context Problem was the sort of thing most civilisations encountered just once, and which they tended to encounter rather in the same way a sentence encountered a full stop. The usual example given to illustrate an Outside Context Problem was imagining you were a tribe on a largish, fertile island; you’d tamed the land, invented the wheel or writing or whatever, the neighbours were cooperative or enslaved but at any rate peaceful and you were busy raising temples to yourself with all the excess productive capacity you had, you were in a position of near-absolute power and control which your hallowed ancestors could hardly have dreamed of and the whole situation was just running along nicely like a canoe on wet grass . . . when suddenly this bristling lump of iron appears sailless and trailing steam in the bay and these guys carrying long funny-looking sticks come ashore and announce you’ve just been discovered, you’re all subjects of the Emperor now, he’s keen on presents called tax and these bright-eyed holy men would like a word with your priests.

That was an Outside Context Problem; so was the suitably up-teched version that happened to whole planetary civilisations when somebody like the Affront chanced upon them first rather than, say, the Culture.

The Culture had had lots of minor OCPs, problems that could have proved to be terminal if they’d been handled badly, but so far it had survived them all. The Culture’s ultimate OCP was popularly supposed to be likely to take the shape of a galaxy-consuming Hegemonising Swarm, an angered Elder civilisation or a sudden, indeed instant visit by neighbours from Andromeda once the expedition finally got there.

In a sense, the Culture lived with genuine OCPs all around it all the time, in the shape of those Sublimed Elder civilisations, but so far it didn’t appear to have been significantly checked or controlled by any of them. However, waiting for the first real OCP was the intellectual depressant of choice for those people and Minds in the Culture determined to find the threat of catastrophe even in utopia.

‘Almost. Maybe,’ agreed the apparition. ‘Perhaps it’s a little less likely to be so with your help.’