d that
all events in space-time occur according to maximum probability, but I
just don't get this alternate probability stuff, at all. If something
exists, it's because it's the maximum-probability effect of prior
causes; why does anything else exist on any other time-line?"

Verkan Vall blew smoke at the air-renovator. A lecture on paratime
theory would nicely fill in the three-hour interval until the landing
at Dhergabar. At least, this kid was asking intelligent questions.

"Well, you know the principal of time-passage, I suppose?" he began.

"Yes, of course; Rhogom's Doctrine. The basis of most of our psychical
science. We exist perpetually at all moments within our life-span; our
extraphysical ego component passes from the ego existing at one moment
to the ego existing at the next. During unconsciousness, the EPC is
'time-free'; it may detach, and connect at some other moment, with the
ego existing at that time-point. That's how we precog. We take an
autohypno and recover memories brought back from the future moment
and buried in the subconscious mind."

"That's right," Verkan Vall told him. "And even without the autohypno,
a lot of precognitive matter leaks out of the subconscious and into
the conscious mind, usually in distorted forms, or else inspires
'instinctive' acts, the motivation for which is not brought to the level
of consciousness. For instance, suppose, you're walking along North
Promenade, in Dhergabar, and you come to the Martian Palace Cafe, and
you go in for a drink, and meet some girl, and strike up an acquaintance
with her. This chance acquaintance develops into a love affair, and
a year later, out of jealousy, she rays you half a dozen times with
a needler."

"Just about that happened to a friend of mine, not long ago," the pilot
said. "Go on, sir."

"Well, in the microsecond or so before you die--or afterward, for that
matter, because we know that the extraphysical component survives
physical destruction--your EPC slips back a couple of years, and
re-connects at some point pastward of your first meeting with this
girl, and carries with it memories of everything up to the moment of
detachment, all of which are indelibly recorded in your subconscious
mind. So, when you re-experience the event of standing outside the
Martian Palace with a thirst, you go on to the Starway, or Nhergal's,
or some other bar. In both cases, on both time-lines, you follow the
line of maximum probability; in the s