Now there are excellent reasons, other than those based on analogy,
that the fourth-dimensional aspect of things may manifest itself to
our ordinary experience, not as spatial extension, but as temporal
change. Then, if we conceive of clairvoyance as a transcending by
consciousness of our three-dimensional space, prevision and
post-vision would be logically possible as corresponding to the
positive and negative of the fourth dimension. This may be made
clearer by the aid of a homely illustration.


PISGAH SIGHTS OF LIFE'S PAGEANT

Suppose you are standing on a street corner, watching a procession
pass. You see the pageant as a sequence of objects and individuals
appearing into view near by and suddenly, and disappearing in the
same manner. This would represent our ordinary waking consciousness
of what goes on in the world round about. Now imagine that you walk
up the street in a direction opposite to that in which the
procession is moving. You then rapidly pass in review a portion of
the procession which had not yet arrived at the point you were a few
moments before. This would correspond to the seeing of something
before it "happened," and would represent the positive aspect of
clairvoyance in time--prevision. Were you to start from your
original position, and moving in the direction in which the
procession was passing, overtake it at some lower street corner, you
could witness the thing you had already seen. This would represent
post-vision--clairvoyance of the past.

A higher type of clairvoyance would be represented by the sweep of