"We don't know for sure because you can't prove a negative," he went on to his son, laying down his pen. Doreen gave him a smile, as her quill went scratching on over the paper before her. "That means you can't-"

"Yeah, I got that part, Dad," David said, kicking his sandals against the legs of his chair. "It's the rest I don't get."

"Okay. Well, first, when you've got an idea about why things are the way they are, a hypothesis-" The seven-year-old silently shaped the word. "-a hypothesis, you've got to test it. If things in the real world, things you can prove, work out the way your hypothesis says they should, then chances are your hypothesis is right."

"Yeah," the boy said, frowning in concentration. "Yeah, but what about stuff we can't test? Negatives, like you said."

"Well, we've got two rules for that," Ian went on patiently. God, I've got a sharp one here. "The first is that the simplest way to explain something is best, if it explains everything you can see. That's called Occam's razor. Don't make things more complicated than you have to."

"Hey, that makes a lot of sense!" David said, his face lighting up.

Sharp, indeed. There were a lot of adults who didn't get that; on the other hand, it would have been more flattering still if his son hadn't sounded very slightly surprised. David was moving from the parents-are-infallible stage toward the parents-know-nothing stage earlier than most kids, obviously.

"What's the other rule. Dad?"

"Well, this is a little more difficult," he hedged. "It's called finding out whether your hypothesis is falsifiable or nonfalsifiable."

He was still deep in the toils of Sir Karl Popper's epistemology when the whistle beside the tall smokestack tooted. They were coming in to Ur Base, and it was time to get back to work.

"Hey, I can explain all this staff to the other kids!" David said enthusiastically.

Ian nodded, wincing inwardly; he could see the same expression in Doreen's eyes. They'd both liked doing that too, as children. David would have to learn for himself exactly how popular it made you.

Swindapa made a gesture with her right hand, palm down. Marian froze, eyes scanning the tangle of jungle ahead. Insects buzzed, some of them pausing to sip at her sweat or to sting; the thick vegetation was full of rustles, squeaks, clicks. A brief wind murmured through the dense green, bringing a little relief from the humid heat.

"There," the younger woman murmured, turning her head so the sound would not carry.

The antelope were in the clearing ahead, cropping at bush along its fringe. Fawn-colored with whitish bellies, twin spiral horns, big dewlaps below their throats, about the size of a large ox. They were eland, six of them, a bull and five females. Alston lifted her rifle, careful to make the movement slow and gradual. The sharp click as she pulled the hammer back to full cock with her right thumb made one of the big antelope raise its head, still chewing but scanning for the unfamiliar sound. Her mind closed in, limiting the world to a patch of pale brown hide behind the shoulder.

Stroke the trigger. Crack! Swindapa's shot followed, so close to hers that the two reports might as well have been one.

The eland gave a twisting leap and staggered a few steps before collapsing, with blood running bright crimson and frothy from its nostrils. Its companions had already left at a plunging trot through the scrub and vines, heads held high and eyes wide. Swindapa's went down even faster; when they had slung their rifles and advanced to the bodies, Alston saw that it had been a neck shot, clean through the spine.

"Show-off," she said.

Swindapa laughed, then sobered as she cut a branch and dipped it in the blood, shaking it to the four quarters of the compass and chanting. Alston remembered that from the first time they'd hunted together- on Nantucket, back when the Island had to shoot out its deer to protect the first crops. Now she could understand the words in the Old Tongue, apologizing and explaining to the spirit of the animal why this was needful, singing the ghost home to the Mother. She waited respectfully until the ceremony was done, then turned and put thumb and forefinger to her lips to whistle summons.

"These are not as the others," a small brown man whispered to his companion.

"They use the sticks that make a noise and kill," his companion replied. "Like the other Bad Ones."

The men-alike enough to be brothers and actually cousins- crouched easily in the upper branches of a tree. Neither was more than an inch over five feet; their cheekbones were high and their eyes slanted in yellow-brown faces. The hair of their heads was naturally twisted into tight peppercorns, that on their bodies was scant. An observer could have seen that easily, since neither wore more than a piece of soft leather drawn up between the legs and over a thong belt; they carried small bows, and quivers of arrows whose chipped-stone heads were carefully wrapped in leaves to preserve the sticky vegetable poison that tipped them. Their language was full of sharp tongue clicks and plosives spat from the back of the mouth.

"See, though, they are women," the first man said, pointing to the figures in the clearing downslope. "The others were all men."

"Well, they had to have women somewhere," his cousin replied. "Unless they crawled out from under rocks, like grubs."

"And one has yellow hair, while the other has skin black as the rock that burns," the first man argued. "None of the Bad Ones looked so. The hides they wrap their bodies in are different, too."

"Perhaps they are another clan of the Bad Ones."

"Perhaps. We will follow them."

"Carefully," the first man to speak said. "These are not quite so clumsy in the bush, either."

King Shuriash was far too proud a man to show emotion before a foreigner, particularly anguish over so slight a thing as a concubine's likely death in childbirth, and that during a war as well. But Lieutenant (Medical Corps, Republic of Nantucket Coast Guard) Justin Clements recognized it well enough.

"Can you save her?" the Babylonian asked abruptly.

"My lord king, that I cannot answer until I have seen the woman," the doctor said. "It may be that I can; it may be that it is beyond my powers or that it is too late."

Shuriash's heavy-featured face showed somber approval. "It is well," he said. "So many promise more than they can do, especially to kings." A wry, difficult smile showed strong yellow teeth. "But I have noticed that you Nantukhtar are more likely to throw the truth in my beard than to dip it in honey. Will you try?"

"It is an honor to help the household of our host, lord king," he said-or hoped he'd said; this archaic-Semitic language was awkward in his mouth, despite nearly a year's drill.

"Very well," the king said. To the eunuch guards: "Show him to the women's quarters, him and his assistants."

The journey wasn't long, although the tall, dim corridors of the palace were a labyrinth. And the eunuchs make my skin crawl, he thought. Poor bastards. It was mostly the thought of deliberate mutilation that disgusted him, but part of it was sheer elemental repulsion. And maybe it's because one reason they don't look more mutinous than they do is that I'm clean-shaven-which no man in the land of Kar-Duniash was-and because, face it, I'm a little plump too. Objectively the eunuchs knew he was a whole man. Subconsciously, they probably perceived him as one of their own.

The passages of the palace wound inward, hung with bright knotted or woven rugs up to head height while the walls above bore scenes of palm trees, griffins and fabulous beasts, winged hawk-headed men bearing objects that probably meant something if you knew the symbolism. The floor was terra-cotta, covered in woven mats of rush or straw dyed in pleasing colors; the whole effect should have been gaudy but wasn't, and it lightened the massiveness of the adobe architecture. At last they crossed an open courtyard, and thence into a last suite of rooms.