‘Because . . . Well, for lots of reasons, but for one thing it’s only if you know the truth about the world that you can really understand it and make it different.’

‘And why would you want to make the world different?’

‘Well, to make life better, and richer, and—’

‘And why would you want to do that?’

‘Because . . . Sacred Earth, Gaia, why the interrogation? What point are you trying to make?’

‘That even supersmart, superrational Marius has things he just believes in.’

He half-smiled, like he was conceding I’d very nearly got one over on him, even if not quite. ‘I guess. In a sort of way. But come on, be honest with me, Gaia, what would you prefer: to have the intellectual vistas that are available to us, or to be stuck inside this infantile story that the Eden folk tell each other? I mean, look at Trueheart! Look at that sheer hunger she has for knowledge.’

‘Fair point. Though most people aren’t like Trueheart, here or on Earth. But we can’t give Trueheart or anyone else here the knowledge we have, however much they might want it. We can’t build universities for them. We can’t teach them the whole of science, or even the beginnings of it. Yes, we can easily destroy their old stories if we choose to, but we’ve got nothing to give them to put in their place.’

Marius shrugged. ‘Well, that’s up to them, isn’t it? They’re not kids, Gaia. It’s not our business to protect them from the truth. It’s up to them what they do with it, but it’s our job to give it to them as best we can.’

Deep nodded. ‘Marius is right about that, Gaia. We don’t have a right to hide things from them.’

‘I know,’ I said. ‘I accept that. But their beliefs aren’t nonsense, Marius. I’m not having that. They’re not literally true, I grant you, but that doesn’t mean there’s no truth in them. Truth isn’t some binary yes–no thing, as you seem to think. All kinds of wisdom can be wrapped in old stories. Throw away the story and you throw away the wisdom as well.’

‘I agree with you, Gaia,’ said Deep, ‘but you need to remember that whatever we tell them or don’t tell them, their beliefs will still have to change, just to cope with the new situation the three of us have created simply by being here.’

I stood up and looked out through the clear dome of our flying saucer, at the people out there in the eerie glow of the trees round the clearing, waiting for a glimpse of us. Such a tiny outpost of humankind, they were, and so incredibly far away from everyone else. No wonder they were excited to have us there.