ed his
Handbook, "_can be resolved by any other group, regardless of ideology
or conditioning, because the basic perceptive abilities of both must be
the same through identical heredity_."

"If it's an imitation, and this is another Hymenop experiment in
condition ecology, then we're stumped to begin with," Gibson finished.
"Because we're not equipped to evaluate the psychology of alien
motivation. We've got to determine first which case applies here."

* * * * *

He waited for Farrell's expected irony, and when the navigator
forestalled him by remaining grimly quiet, continued.

"The obvious premise is that a Terran ship must have been built by
Terrans. Question: Was it flown here, or built here?"

"It couldn't have been built here," Stryker said. "Alphard Six was
surveyed just before the Bees took over in 3025, and there was nothing
of the sort here then. It couldn't have been built during the two and a
quarter centuries since; it's obviously much older than that. It was
flown here."

"We progress," Farrell said dryly. "Now if you'll tell us _how_, we're
ready to move."

"I think the ship was built on Terra during the Twenty-second Century,"
Gibson said calmly. "The atomic wars during that period destroyed
practically all historical records along with the technology of the
time, but I've read well-authenticated reports of atomic-driven ships
leaving Terra before then for the nearer stars. The human race climbed
out of its pit again during the Twenty-third Century and developed the
technology that gave us the Ringwave. Certainly no atomic-powered ships
were built after the wars--our records are complete from that time."

Farrell shook his head at the inference. "I've read any number of
fanciful romances on the theme, Gib, but it won't stand up in practice.
No shipboard society could last through a thousand-year space voyage.
It's a physical and psychological impossibility. There's got to be some
other explanation."

* * * * *

Gibson shrugged. "We can only eliminate the least likely alternatives
and accept the simplest one remaining."

"Then we can eliminate this one now," Farrell said flatly. "It entails a
thousand-year voyage, which is an impossibility for any gross reaction
drive; the application of suspended animation or longevity or a
successive-generation program, and a final penetration of
Hymenop-occupied space to set up a colony under