only necessary, but sufficient. In such a case, the
accuracy was perfect, the hits one hundred per cent.

But the evasive action taken by a human pilot, aided by a randomity
selector, is not logical and therefore cannot be handled by a computer.
Like the path of a microscopic particle in Brownian motion, its position
can only be predicted statistically; estimating its probable location is
the best that can be done. And, in space warfare, probability of that
order is simply not good enough.

To compute such an orbit required a special type of human mind, and
therefore a special type of human. It required a Guesser.

The way a Guesser's mind operated could only be explained _to_ a Guesser
_by_ another Guesser. But, as far as anyone else was concerned, only the
objective results were important. A Guesser could "guess" the route of a
moving ship, and that was all anyone cared about. And a Master Guesser
prided himself on his ability to guess accurately 99.999% of the time.
The ancient sport of baseball was merely a test of muscular
co-ordination for a Guesser; as soon as a Guesser child learned to
control a bat, his batting average shot up to 1.000 and stayed there
until he got too old to swing the bat. A Master Guesser could make the
same score blindfolded.

Hitting a ship in space at ultralight velocities was something else
again. Young Kraybo could play baseball blindfolded, but he wasn't yet
capable of making the master guesses that would protect a merchantship
like the _Naipor_.

But what was the matter with him? He had, of course, a fire-control
computer to help him swing and aim his guns, but he didn't seem to be
able to depend on his guesswork. He had more than once fired at a spot
where the computer said the ship would be instead of firing at the spot
where it actually arrived a fraction of a second later.

There were only two things that could be troubling him. Either he was
doing exactly as he said--ignoring his guesses and following the
computer--or else he was inherently incapable of controlling his
guesswork and was hoping that the computer would do the work for him.

If the first were true, then Kraybo was a fool; if the second, then he
was a liar, and was no more capable of handling the fire control of the
_Naipor_ than the captain was.

The Guesser hated to have Kraybo punished, really, but that was the only
way to make a youngster keep his mind on his business.

_After all_, thought The Guesser,