"Not exactly," said the Medical Man. "There are balloons."
"But before the balloons, save for spasmodic jumping and the inequalities of the surface, man had no freedom of vertical movement."
"Still they could move a little up and down," said the Medical Man.
"Easier, far easier, down than up."
"And you cannot move at all in Time. You cannot get away from the present moment."
"My dear sir, that is just where you are wrong. That is just where the whole world has gone wrong. We are always getting away from the present moment. Our mental existences, which are immaterial and have no dimensions, are passing along the Time Dimension with a uniform velocity from the cradle to the grave. Just as we should travel down if we began our existence fifty miles above the earth's surface."
"But the great difficulty is this,"
