do not know how the Delphic oracle found out the right answer, but various
easy methods of fraud at once occur to the mind. However, the procedure of
Croesus, if he took certain precautions, was relatively scientific.
Relatively scientific also was the inquiry of Porphyry, with whose
position our own is not unlikely to be compared. Unable, or reluctant, to
accept Christianity, Porphyry 'sought after a sign' of an element of
supernormal truth in Paganism. But he began at the wrong end, namely at
Pagan spiritualistic _séances_, with the usual accompaniments of darkness
and fraud. His perplexed letter to Anebo, with the reply attributed to
Iamblichus, reveal Porphyry wandering puzzled among mediums, floating
lights, odd noises, queer dubious 'physical phenomena.' He did not begin
with accurate experiments as to the existence of rare, and apparently
supernormal human faculties, and he seems to have attained no conclusion
except that 'spirits' are 'deceitful.'[1]

Something more akin to modern research began about the time of the
Reformation, and lasted till about 1680. The fury for burning witches led
men of sense, learning, and humanity to ask whether there was any reality
in witchcraft, and, generally, in the marvels of popular belief. The
inquiries of Thyraeus, Lavaterus, Bodinus, Wierus, Le Loyer, Reginald
Scot, and many others, tended on the whole to the negative side as regards
the wilder fables about witches, but left the problems of ghosts and
haunted houses pretty much where they were before. It may be observed that
Lavaterus (circ. 1580) already put forth a form of the hypothesis of
telepathy (that 'ghosts' are hallucinations produced by the direct action
of one mind, or brain, upon another), while Thyraeus doubted whether the
noises heard in 'haunted houses' were not mere hallucinations of the sense
of hearing. But all these early writers, like Cardan, were very careless
of first-hand evidence, and, indeed, preferred ghosts vouched for by
classical authority, Pliny, Plutarch, or Suetonius. With the Rev. Joseph