“Okay - tell me more.”
“Well, a spaceship travels to a far-off planet-...”
“Uh - light years.”
“So it has some way of travelling faster than light and violating all the known laws of physics? Warp drive or wormholes?”
“Uh - whichever. And artificial gravity, and it’s controlled by an artificial intelligence, and when they get there they beam down by teleport. Right?”
“And they evangelise the aliens with the good news of Jesus Christ. You see? It’s a brilliant way of making the gospel known to a modern generation who dig this kind of thing.”
“So: the modern generation are meant to realise that you’re making up the warp drive and artificial gravity and AI and teleport, but the bit about the risen God is true?”
“You know you could have all that, but they preach the risen Horus instead, with exactly the same result?”
That, in a nutshell, summarises most of my early attempts to write Christian science fiction, which is why it was so bad and no one will ever read it. So I looked to see how successful Christian writers did it. How did Lewis make the Lion work?
Well, in writing, as in real life, there is a difference between preaching and witnessing. Even if God puts in a personal appearance in your story, if it’s to work then the story isn’t about God - it’s about other people’s reactions to him. In the Narnia chronicles, what has impact isn’t so much Aslan’s didactic statements as the different ways the characters handle him. (And that opens the door to the didactic statements: Lewis is both preacher and witness, which is not incompatible.)
My wife recently pointed out a glaring implausibility in the Parable of the Sower, which is that no one goes forth to sow without doing a modicum of soil preparation. Not everyone is called to preach (see Ephesians 4.11 and, if there was any doubt, the Daily Telegraph) but everyone is called to make disciples (Matthew 28.19). So it may well be that some of us are called to be preachers and others soil preparers, readying other people’s hearts for the seed to be sown by a third party. The parable provides a handy guide to the different soil types that can be expected.
It doesn’t matter if your humans are living on a starship or a far-off world or just down the road in 21st century Britain. If the human reactions to situations with which the reader is familiar ring true, then whatever else they do and say will also be convincing. Your writing will condition their hearts and minds ready to receive more. It’s not so much a matter of force-feeding Christianity as leaving a Christian aftertaste.
Which is a lot harder.