Schild's Ladder

by Greg Egan

Finally found a story that might rival "House of Suns."

Once he'd told the crib on Turaev that his birth flesh could be recycled, he'd given up the notion that somewhere there'd always be a room waiting for him.

What if you could transmit the data that make up your mind to a clone of yourself on another world?

“My father didn't come right out and state that all their earlier informants had lied to them, but he explained that—apart from a few surviving contemporaries of the travelers themselves—there'd been nothing resembling sexual dimorphism in the descendants of humans, anywhere, for more than nineteen thousand years. Long before any extrasolar world was settled, it had gone the way of war, slavery, parasites, disease, and quantum indecisiveness. And apart from trivial local details, like the exact age of sexual maturity and the latency period between attraction and potency, he and his lover embodied a universal condition: they were both, simply, people. There were no other categories left to which they could belong.”

We should be able to adapt. If the ocean comes a few meters inshore, you retreat. A few kilometers, you build a dike. A few thousand...you learn to live in boats.

“It's beautiful, isn't it?” his father said. “This is called Schild's ladder. All throughout geometry, all throughout physics, the same idea shows up in a thousand different guises. How do you carry something from here to there, and keep it the same? You move it step by step, keeping it parallel in the only way that makes sense. You climb Schild's ladder.” Tchicaya didn't ask if the prescription could be extended beyond physics; as an answer to his fears, it was only a metaphor. But it was a metaphor filled with hope. Even as he changed, he could watch himself closely, and judge whether he was skewing the arrow of his self.

It had been less than a millisecond since the Sarumpaet had begun its flight. Tchicaya enjoyed imagining his own startled near-side version hearing the news that the Planck worms had been defeated, before he'd even had time to grow anxious about the fate of the mission. He'd made no firm plans for reversing his bifurcation, since he'd never really expected to return, but the less-traveled Tchicaya would probably be willing to be subsumed. If not, he only hoped that their continued separation would be justified, and they didn't merely dog each other's footsteps. If they both tried to meet up with Rasmah it would be awkward, though Tchicaya had little doubt which one of them she'd choose.