The ether of space, because it has at last found entrance, must be
given a grudging hospitality in these pages, even though the
mysterious stranger prove but a ghost. The Relativists would have it
that with the acceptance of their point of view the ether may be
eliminated; but if they take away the ether, they must give us
something in its stead. In whatever way the science of the future
disposes of this problem, it must take into account the fact of
light transmission. On the theory that the ether is an elastic solid
of amazing properties, in which the light waves vibrate _transversely_
to their direction, it assists the mind to think of the ether as
four-dimensional, because then a light wave would be a superficial
disturbance of the medium--superficial, but three-dimensional, as
must needs be the case with the surface of a four-dimensional solid.
* * * * *
This search for evidences of hyper-dimensionality in the universe
accessible to our senses is like looking, not for a needle in a
haystack, but for a haystack in a needle--for the greater in the less.
From the purely physical evidences, all that can with certainty be
said is that the hypothesis is not inconsistent with the facts of
science or its laws; that it is being verified and rendered more
probable by the investigations of science; that it is applicable to
the description or explanation of all the observed phenomena, and
assigns a cause fully adequate to have produced them.
Now there is an order of phenomena that we call psychic. Because
they are phenomenal they cannot occur outside of time and space
altogether; because they are psychic they defy explanation in terms
of the space and time of every-day life. Let us next examine these
in the light of our hypothesis.