Ruins

He stood at the verifying machine, holding the hilt of the knife into the field. “Is the jewel of control for this vessel present here?”

“It is,” said the ship’s computer.

“Rigg Sessamekesh gave me this knife,” said Umbo. “I take command of this vessel as Rigg’s subordinate.”

There was a slight hesitation. “Did Rigg authorize this procedure?” asked the ship’s computer.

“Is this the jewel of control?” asked Umbo.

“Yes.”

“Did Rigg Sessamekesh give this jewel to me as part of the knife?”

“He did.”

“I take command of this vessel as Rigg’s subordinate.”

Another hesitation. “Certified.”

“Command all expendables attached to this ship to obey me and cause me no harm.”

“Done.”

“Is the expendable still on the bridge with the other two copies of me?”

“No,” said the ship’s computer. “He killed them both and is on his way to this place.”

Umbo shuddered. “Command him to come into this room walking backward. He is forbidden to look at me.”

Moments later, Odinex backed into the room.

“Stop,” said Umbo.

The expendable stopped.

“This ship, and all the equipment of this ship, will hereby define ‘human being’ as ‘organism descended in an unbroken line from the colonists of one or more of the ships commanded by Ram Odin on their voyage to Garden.’ Do you understand?”

“Yes,” said the expendable.

“Yes,” said the ship’s computer.

“Am I human?”

“Yes,” they both answered without hesitation.

“Who can change this definition?”

“You can,” said the ship and the expendable.

“Let one speak for both,” said Umbo.

The ship’s computer fell silent.

“You and Rigg Sessamekesh can change this definition,” said Odinex.

“Who else?”

“No one.”

Umbo knew this was not true, but also knew that the computers couldn’t lie.

“Is there a procedure by which someone else can gain the authority to change this definition without my or Rigg’s consent?”

“Yes.”

“Can you disable all procedures that would allow us to be superseded?”

“No.”

“Can I disable them?”

“Yes,” said the expendable.

In this situation, Umbo didn’t trust simple answers. “And if I do, what will be the consequences?”

“The orbiter will obliterate all life within this wallfold.”

Umbo sighed. “I will not attempt to disable those procedures.”

Odinex said nothing.

“Turn and face me, Odinex,” said Umbo.

Odinex faced him.

“You killed me twice today.”

“I killed expendable copies of yourself,” said Odinex. “They came into existence because you jumped back in time, and by appearing in their presence, you changed their actions so when they reached the point in time when you time-shifted, they did not time-shift, and therefore they did not disappear.”

“How long might such duplicates continue to exist?” asked Umbo.

“Until they die.”

Umbo had never thought of this possibility. But it gave him a better understanding of how the duplicate ships had come into existence at the beginning of the human settlement of Garden.

“How did you kill them?” asked Umbo.

“I broke their necks and cast them off the bridge.”

“You are forbidden ever to destroy copies of me or any other time-shifter, without specific instructions to do so.”

“And which copy should I obey?” asked Odinex.

“The most recent one.”

“And how will I know which one that is?” asked Odinex.

“I’ll try to make sure it never comes up.”

“That would be best.”

“Odinex, show me everything on this ship that is not included in the plans that I studied in the library near the Wall.”

“The plans are complete.”

“No they’re not,” said Umbo. “They don’t show, for instance, where the spare copies of you are stored.”

“Intact copies of me are not stored anywhere. If this module fails, then a new one is assembled from the parts in parts storage, which is clearly labeled in the plans.”

“What triggers the creation of a new expendable?” asked Umbo.

“A death signal,” said Odinex. “A request for duplication. Loss of higher functions in the present module. Failure to communicate at any level for ten hours.”

“Who can issue the request for duplication?”

“The existing module. The certified commander of the vessel and all superior officers.”

“Thank you,” said Umbo. “Are the duplicates bound to obey all orders previously given to the earlier copy?”

“Yes,” said Odinex. “We are memory-identical.”

“Am I human, Odinex?”

“You are.”

“Is that what you’ll report to the Visitors when they arrive from Earth?”

“They will get a full memory dump of these events, along with all others,” said Odinex.

“They’ll see me make copies of myself by time-jumping?”

“Yes.”

Umbo wanted to grin, but restrained himself. Let the Visitors chew on that.

Then his pleasure faded. Seeing Umbo time-shift might well be a death sentence for Garden. To see someone suddenly pop into existence behind himself, and then again, so three copies exist at once—that wouldn’t exactly reassure the humans from Earth.

Well, it’s not as if they weren’t going to destroy Garden anyway. They’ve done it nine times already, and until now without any provocation from time-shifters.

It’s hard to imagine that I’ve somehow made the destruction of Garden worse. Will they say bad words while they wipe out all life on Garden? Will they throw stones at the corpses?

“Odinex, the jewels of control are not mentioned in the plans of the ship, or the computer manuals.”

The expendable said nothing.

“Consider that to be a question, and answer me,” said Umbo.

“The jewels are thoroughly explained in the plans and manuals.”

Umbo thought for a moment. “Under what name are they explained?”