"Yes."

"Then let's go. I won't need to eat till noon."

You take a step, then another. That's the journey. But to take a step with your eyes open is not a journey at all, it's a remaking of your own mind. You see things that you never saw before. Things never seen by the eyes of human beings. And you see with your particular eyes, which were trained to see not just a plant, but this plant, filling this ecological niche, but with this and that difference.

And when your eyes have been trained for forty years to be familiar with the patterns of a new world, then you are Antonie van Leeuwenhoek, who first saw the world of animalcules through a microscope; you are Carl Linnaeus, first sorting creatures into families, genera, species; you are Darwin, sorting lines of evolutionary passage from one species to another.

So it was not a rapid journey. Sel had to force himself to move with any kind of haste.

"Don't let me linger so long over every new thing I see," he told Po. "It would be too humiliating for my great expedition to take me only ten kilometers south of the colony. I must cross the first range of mountains, at least."

"And how will I keep you from lingering, when you have me photographing and sampling and storing and recording notes?"

"Refuse to do it. Tell me to get my bony knees up off the ground and start walking."

"All my life I'm taught to obey my elders and watch and learn. I'm your assistant. Your apprentice."

"You're just hoping we don't travel very far so when I die you don't have so long to carry the corpse."

"I thought my father told you — if you actually die, I'm supposed to call for help and observe your decomposition process."

"That's right. You only carry me if I'm breathing."

"Or do you want me to start now? Hoist you onto my shoulders so you can't discover another whole family of plants every fifty meters?"

"For a respectful, obedient young man, you can be very sarcastic."

"I was only slightly sarcastic. I can do better if you want."

"This is good. I've been so busy arguing with you, we've gone this far without my noticing anything."

"Except the dogs have found something."

It turned out to be a small family of the horned reptile that seemed to fill the bunny rabbit niche — a big-toothed leaf-eater that hopped, and would only fight if cornered. The horns did not seem to Sel to be weapons — too blunt — and when he imagined a mating ritual in which these creatures leapt into the air to butt their heads together, he could not see how it could help but scramble their brains, since their skulls were so light.

"Probably for a display of health," said Sel.

"The antlers?"

"Horns," said Sel.

"I think they're shed and then regrown," said Po. "Don't these animals look like skin-shedders?"

"No."

"I'll look for a shed skin somewhere."

"You'll have a long look," said Sel.

"Why, because they eat the skins?"

"Because they don't shed."

"How can you be sure?"

"I'm not sure," said Sel. "But this is not a formic import, it's a native species, and we haven't seen any skin shedding from natives."

So went the conversation as they traveled — but they did cover the ground. They took pictures, yes. And now and then, when it was something really new, they stopped and took samples. But always they walked. Sel might be old and need to lean on his walking stick now and then, but he could still keep up a steady pace. Po was likely to move ahead of him more often than not, but it was Po who groaned when Sel said it was time to move on after a brief rest.

"I don't know why you have that stick," said Po.

"To lean on when I rest."

"But you have to carry it the whole time you're walking."

"It's not that heavy." "It looks heavy."

"It's from the balsa tree — well, the one I call 'balsa, since the wood is so light."

Po tried it. Only about a pound, though it was thick and gnarled and widened out at the top like a pitcher. "I'd still get tired of carrying it."

"Only because you put more weight in your backpack than I did."

Po didn't bother arguing the point.

"The first human voyagers to Earth's moon and the other planets had an easy time of it," said Po, as they crested a high ridge. "Nothing but empty space between them and their destination. No temptation to stop and explore."

"Like the first sea voyagers. Going from land to land, ignoring the sea because they had no tools that would let them explore to any depth."

"We're the conquistadores," said Po. "Only we killed them all before we ever set foot on land."

"Is that a difference or a similarity?" asked Sel. "Smallpox and other diseases raced ahead of the conquistadores."

"If only we could have talked to them," said Po. "I read about the conquistadores — we Mayans have good reason to try to understand them. Columbus wrote that the natives he found 'had no language, merely because they didn't understand any of the languages his interpreters knew."

"But the formics had no language at all."

"Or so we think."

"No communication devices in their ships. Nothing to transmit voice or images. Because there was no need of them. Exchange of memory. Direct transfer of the senses. Whatever their mechanism was, it was better than language, but worse, because they had no way to talk to us."

"So who were the mutes?" asked Po. "Us, or them?"

"Both of us mutes," said Sel, "and all of us deaf."

"What I wouldn't give to have just one of them alive."

"But there couldn't be just one," said Sel. "They hived. They needed hundreds, perhaps thousands to reach the critical mass to achieve intelligence."

"Or not," said Po. "It could also be that only the queen was sentient. Why else would they all have died when the queens died?"

"Unless the queen was the nexus, the center of a neural network, so they all collapsed when she did. But until then, all of them individuals."

"As I said, I wish we had one alive," said Po, "so we could know something instead of guessing from a few desiccated corpses."

Sel silently rejoiced that yet another generation of this colony had produced at least one who thought like a scientist. "We have more of them preserved than any of the other colonies. Here, there are so few scavengers that can eat them, the corpses lasted long enough for us to get to the planet's surface and freeze some of them. We actually got to study structure."

"But no queens."

"The sorrow of my life," said Sel.

"Really? That's your greatest regret?"

Sel fell silent.

"Sorry," said Po.

"It's all right. I was just considering your question. My greatest regret. What a question. How can I regret leaving everything behind on Earth, when I left it in order to help save it? And coming here allowed me to do things that other scientists could only dream of. I have been able to name more than five thousand species already and come up with a rudimentary classification system for an entire native biota. More than on any of the other formic worlds."

"Why?"

"Because the formics stripped those worlds and then established only a limited subset of their own flora and fauna. This is the only world where most of the species evolved here. The only place that's messy. The formics brought fewer than a thousand species to their colonies. And their home world, which might have had vastly more diversity, is gone."

"So you don't regret coming here?"

"Of course I do," said Sel. "And I'm also glad to be here. I regret being an old wreck of a man. I'm glad I'm not dead. It seems to me that all my regrets are balanced by something I'm glad of. On average, then, I have no regrets at all. But I'm also not a bit happy. Perfect balance. On average, I don't feel anything at all. I think I don't exist."