Strata

different forces, maddened by different moons, bent by different gravities.
    Since the universe could not be said to have a natural ending, because the universe was not natural but only the sum of the lives that had shaped it, Men intended to live for ever. Why not?
    Preserve meme pools, preserve ideas, that was the secret. If you had a hundred planets there was room for different sciences, curious beliefs, new techniques, old religions to flourish in quiet corners. Earth had been one united civilization and had nearly perished once because of it.Diversify enough, and somewhere you’ll always find someone capable of catching anything the future throws at you.
    People on a disc guarded by demons and ringed with a waterfall, what memes would they contribute to the genetics of civilization? She tried to explain to Marco.
    ‘What are memes?’ said Marco.
    ‘Memes are – ideas, attitudes, concepts, techniques,’ said Kin. ‘Mental genes. Trouble is, all the memes likely to develop on the disc are host-destructive. Anthropocentricity is one.’
    A pale red moon rose above the curdled clouds. Now they flew a mile apart, flew high and fast to make the hours count. Kin kept an eye on the speck that was Silver, and worried.
    Quite wrong, of course, to project human thought patterns on an alien, but a man in Silver’s position would live in hope that sooner or later food would be forthcoming. Men were optimists.
    You couldn’t expect a shand to think like a man. It was so easy to think of your friends as humans in a skin, and for good and noble reasons people were encouraged to think of aliens as funny-shaped men. Just because they learned to play poker or read Latin didn’t make them human.
    In short, Kin wondered when Silver would attempt suicide. She signalled Marco and told him.
    ‘We can do nothing,’ he said. ‘I have already decided to eat no food until we reach the hub, as a gesture of solidarity. We could take disc proteins, if the ’waiter’s analysis was right,’ he added.
    ‘Will that make her feel better?’
    ‘It may make
us
feel better. However, there is another problem that has recently forced itself on my attention. I hesitate to mention it—’
    ‘Mention it, mention it.’
    ‘Look at the panel on your left wrist. There’s an orange fluorescent line against a green strip. See it?’
    Kin squinted down in the flickering light.
    ‘I see it. Only it’s an orange dot.’
    ‘Quite, but it should be a line. We really are running out of gas, Kin.’
    They flew in silence for a while. Then Kin asked, ‘How long?’
    ‘About six hours for you and me. Perhaps an hour less for Silver. That will solve one problem. She’ll come to earth miles behind us.’
    ‘Except that we will of course stay with her,’ said Kin flatly. Marco appeared not to have heard.
    ‘If we still had the ’waiter the problem would not have been insurmountable. The hub is not too far. We could have terrorized disc people into transporting us. A hundred suggestions leap to the mind. It might have been quite enjoyable, and good experience.’
    ‘Experience for what?’
    ‘Hobnobbing with the disc folk on a superior basis. I had planned, should the hub hold nothing of interest, to set up an empire. Surely the idea had occurred to you?’
    It had, in passing. Kin thought for a while of Genghis Marco, Marco Caesar, Prester Marco. He could do it, at that. A four-armed god king.
    ‘How long would you say it would take the disc to get onto a space-going footing?’ he asked. ‘If that was made a goal, I mean? We have the knowledge.’
    ‘No, we don’t. We
think
we do, but all we know is how to operate machines. Of course, you could get a spaceship built inside a decade.’
    ‘That soon? Then we could—’
    ‘No we couldn’t.’ Kin had been thinking about this, too. ‘What could be built is a primitive capsule powered by solid-fuel rockets with enough oomph to ram the outer dome. You could launch it by dropping it over the waterfall.’
    ‘First we’d have to unify the disc,’ said Marco thoughtfully. ‘Not difficult. Give me five hundred Norsemen and—’
    ‘There’s Silver,’ said Kin. ‘And, anyway, I have great hopes for the hub.’
    Even so …
    She had been doing a lot of thinking, before they lost the ’waiter. With the ’waiter they might have conquered the disc, filling the void left by the presumably departed disc creators. Withoutit, the best they could hope for was a comfortable life. In a