nment.
It was an attitude of mind. Men accepted its decisions as they would
accept the rulings of a family council, and for the same reasons.

The Brotherhood laid down certain rules but it did not attempt to
enforce them. After all, it didn't need to. It also arbitrated disputes,
admitted new worlds to membership, and organized concerted human effort
against dangerous enemies. And that was all. Yet in its sphere the
authority of the Brotherhood was absolute.

There was only one criterion for membership in the
Brotherhood--membership in the human race. No matter how decadent or
primitive a population might be, if it was human it was automatically
eligible for Brotherhood--a free and equal partner in the society of
human worlds.

Kennon doubted that any nonhuman race had ever entered the select circle
of humanity, although individuals might have done so. A docked Lani, for
instance, would probably pass unquestioned as a human, but the Lani race
would not. In consequence they and their world were fair prey, and had
been attacked and subjugated.

Of course, proof of inhumanity was seldom a problem. Most alien life
forms were obviously alien. But there were a few--like the Lani--where
similarities were so close that it was impossible to determine their
status on the basis of morphology alone. And so the Humanity Test had
come into being.

Essentially it was based upon species compatibility--on the concept that
like can interbreed with like. Tests conducted on every inhabited world
in the Brotherhood had proven this conclusively. Whatever changes had
taken place in the somatic characteristics of mankind since the Exodus,
they had not altered the compatibility of human germ plasm. Man could
interbreed with man--aliens could not. The test was simple. The results
were observable. And what was more important, everyone could understand
it. No definition of humanity could be more simple or direct.

But was it accurate?

Like other Betans, Kennon wondered. It was--so far--probably. The
qualifying phrases were those of the scientist, that strange breed that
refuses to accept anything as an established fact until it is proven
beyond a shadow of a doubt. After all, the human race had been
spaceborne for only six thousand years--scarcely time for any real
differences to develop. But physical changes had already appeared--and
it would only be a question of time before these would probably be
followed by genetic changes. And i