been in 1664 elected a fellow of the recently founded Royal Society and
was in sympathy with its point of view. At the same time he was a
philosopher of no small influence in his generation.

His intellectual position is not difficult to determine. He was an
opponent of the Oxford scholasticism and inclined towards a school of
thought represented by Robert Fludd, the two Vaughans, Henry More, and
Van Helmont,[1] men who had drunk deeply of the cabalistic writers,
disciples of Paracelsus and Pico della Mirandola. It would be foolhardy
indeed for a layman to attempt an elucidation of the subtleties either
of this philosophy or of the processes of Glanvill's philosophical
reasoning. His point of view was partially unfolded in the _Scepsis
Scientifica_, published in 1665[2] and dedicated to the Royal Society.
In this treatise he pointed out our present ignorance of phenomena and
our inability to determine their real character, owing to the
subjectivity of our perceptions of them, and insisted consequently upon
the danger of dogmatism. He himself had drawn but a cockle-shell of
water from the ocean of knowledge. His notion of spirit--if his works on
witchcraft may be trusted--seems to have been that it is a light and
invisible form of matter capable of detachment from or infusion into
more solid substances--precisely the idea of Henry More. Religiously, it
would not be far wrong to call him a reconstructionist--to use a much
abused and exceedingly modern term. He did not, indeed, admit the
existence of any gap between religion and science that needed bridging
over, but the trend of his teaching, though he would hardly have
admitted it, was to show that the mysteries of revealed religion belong
in the field of unexplored science.[3] It was his confidence in the far
possibilities opened by investigation in that field, together with the
cabalistic notions he had absorbed, which rendered him so willing to
become a student of psychical phenomena.

Little wonder, then, that he found the Mompesson and Somerset cases
material to his hand and that he seized upon them eagerly as irrefutable
proof of demoniacal agency. His first task, indeed, was to prove the
alleged facts; these once established, they could be readily fitted into
a comprehensive scheme of reasoning. In 1666 he issued a small volume,
_Some Philosophical Considerations touching Witches and Witchcraft_.
Most of the first edition was burned in the fire of London, but the