William James remarks, in his 'Principles of Psychology,' such solitary
hallucinations of the sane and healthy, once in a life-time, are difficult
to account for, and are by no means rare. 'Sometimes,' Mr. Tylor observes,
'the phantom has the characteristic quality of not being visible to all of
an assembled company,' and he adds 'to assert or imply that they are
visible sometimes, and to some persons, but not always, or to everyone,
is to lay down an explanation of facts which is not, indeed, our usual
modern explanation, but which is a perfectly rational and intelligible
product of early science.'

It is, indeed, nor has later science produced any rational and
intelligible explanation of collective hallucinations, shared by several
persons at once, and perhaps not perceived by others who are present. Mr.
Tylor, it is true, asserts that 'in civilised countries a rumour of some
one having seen a phantom is enough to bring a sight of it to others whose
minds are in a properly receptive state.' But this is arguing in a circle;
What is 'a properly receptive state'? If illness, overwork, 'expectant
attention,' make 'a properly receptive state,' I should have seen several
phantoms in several 'haunted houses.' But the only thing of the sort I
ever saw occurred when I was thinking of nothing less, when I was in good
health, and when I did not know (nor did I learn till long after) that it
was the right and usual phantom to see. Mr. Podmore remarks that various
members of the Psychical Society have sojourned in various 'haunted
houses,' 'some of them in a state of expectancy and nervous excitement,'
which never caused them to see phantoms, for they saw none.[4]

Mr. Tylor treats of waking hallucinations in much the same manner as he
deals with 'travelling clairvoyance.' He does not study them 'in the field
of experience.' He is not concerned with the truth of the facts, important
as we think it would be, but with his theory that hallucinations, among