THE EIGHTEENTH CENTURY
With the eighteenth century came a number of works on demons. One of the more important and seminal of these was Arthur Ashley Sykes's An enquiry into the meaning of demoniacks in the New Testament (London 1737).
Below are some gleanings from the second edition (also from 1737).
In his preface Sykes begins by alluding to Mede's treatise on John 10:20 and then argues that in either case, Christ's miracles of healing are still real: this is a crucial point.
p. 2f: general notion of demons among the Greeks that of departed souls
p. 3: demons also used by Greeks of gods in general
p. 4: [omitting footnotes]
Fourthly, This Notion of Demons, that they were the Souls of such as once had lived upon Earth, is so universally allowed by Jews and Christians as well as by Heathens, that scarce will any one dispute it. Justin Martyr says The Gods of the Heathens are Demons: and more expressly still he calls them The Souls of the deceased. And defining what he meant by Demoniacks, he says, They, who are seized by the Souls of deceased Persons, are such as all Men agree in calling Demoniacks. Josephus calls them the Souls of wicked Men.
The Epilepsy, I say, was looked upon as a Sacred Disease, and was supposed to have its Origin immediately from some or other of the Gods, according as its Symptoms were stronger, or less so; and thence it was called Lues deisica, and Morbus sacer.
pp. 9-10: demon possession believed by some Greeks
We meet with nothing of Demoniacks excepting the Case of Saul, in the Old Testament. But yet Jospehus, (who professes a strict Regard to the Sacred Writings,) mentions certain Charms which Solomon left behind him, by which they could cure Diseases, and so expel Demons, that they should no more return: and this Manner of Cure, says he, continues amongst us even to this Day.