What we need, to prove a ghost, and disprove an _exclusively_
telepathic theory, is a ghost who is not only seen, heard, or even
touched, but a ghost who produces some change in physical objects.
Most provokingly, there are agencies at every successful seance, and
in every affair of the Poltergeist, who do lift tables, chairs,
beds, bookcases, candles, and so forth, while others play
accordions. But then nobody or not everybody _sees_ these agencies
at work, while the spontaneous phantasms which are _seen_ do not so
much as lift a loo-table, generally speaking. In the spiritualistic
cases, we have the effect, with no visible cause; in ghost stories,
we have the visible presence, but he very seldom indeed causes any
physical change in any object. No ghost who does not do this has
any strict legal claim to be regarded as other than a telepathic
hallucination at best, though, as we shall see, some presumptions
exist in favour of some ghosts being real entities.

These rare facts have not escaped a ghost-hunter so intelligent as
Mrs. Henry Sidgwick. This lady is almost too sportsmanlike, for a
psychical researcher, in her habit of giving an apparition the
benefit of every imaginable doubt which may absolve him from the
charge of being a real genuine ghost. 'It is true,' she says, 'that
ghosts are alleged sometimes to produce a physical effect on the
external world;' but to admit this is 'to come into prima facie
collision with the physical sciences' (an awful risk to run), so
Mrs. Sidgwick, in a rather cavalier manner leaves ghosts who produce
physical effects to be dealt with among the phenomena alleged to
occur at seances. Now this is hardly fair to the spontaneous
apparition, who is doing his very best to demonstrate his existence
in the only convincing way. The phenomena of seances are looked on
with deserved distrust, and, generally, may be regarded as an
outworn mode of swindling. Yet it is to this society that Mrs.
Sidgwick relegates the most meritorious and conscientious class of
apparitions.

Let us examine a few instances of the ghost who visibly moves
material objects. We take one (already cited) from Mrs. Sidgwick's
own article. {205} In this case a gentleman named John D. Harry
scolded his daughters for saying that _they_ had seen a ghost, with
which he himself was perfectly familiar. 'The figure,' a fair woman
draped in white, 'on seven or eight occasions appeared in my
bedroom, and twice in the