So, although the seer of Randolph street and all the rest probably
never heard of Duncan Campbell or Nostradamus, or of their
predecessors at Delphi, they have kept the profession of forecasting
remarkably free of innovations.
"This art of prediction," reads Defoe's Life and Adventures of Duncan
Campbell, "is not attainable any otherwise than by these three ways.
1. It is done by the company of familiar spirits and genii, which are
of two sorts (some good and some bad), who tell the gifted person
the things, of which he informs other people. 2. It is performed by
the second sight, which is very various and differs in most of the
possessors, it being only a very little in some, very extensive and
constant in others; beginning with some in their infancy and leaving
them before they come to years, happening to others in a middle age,
to others again in an old age that never had it before, and lasting
only for a term of years, and now and then for a very short period of
time; and in some intermitting, like fits, as it were, of vision that
leave them for a time, and then return to be strong in them as ever;
and it being in a manner hereditary in some families, whose children
have it from their infancy (without intermission) to a great old age,
and even to the time of their death, which they even foretell before
it comes to pass, to a day--nay, even to an hour. 3. It is attained by
the diligent study of the lawful part of the art of magic."