Throughout the Middle Ages it was customary to detect witches by simple tests: their hair could not be cut, they were incapable of shedding tears, they cast no shadows even in bright sunlight. When people started to test these phenomena objectively, in the seventeenth century, they suddenly ceased. Other aspects of witchcraft proved equally insubstantial. For example, victims of witchcraft possessed by demons would often go into fits when they heard certain biblical passages. Doubters hit upon the idea of allowing the possessed to overhear that demons were accomplished linguists, and that the same passage was to be read again this time in Greek or Latin. A passage from a classical pagan author, rather than from the Bible, would then be read aloud in its original language, and was found to elicit the same hysterical response from the ingenuous victim. Just as worrying was the fact that if the possessed person did not know what they were hearing, then genuine biblical passages in Greek or Latin had no effect. As King James I came to realise through using these techniques, supernatural phenomena were matching human expectations.
Rationalism was not universally welcomed. Victims of witchcraft often fell into fits if touched by those who had bewitched them, and this was proof of the witch's power. A simple test was to blindfold "bewitched" people and then let them be touched by a series of different people. It should have been easy to distinguish the true witch from others, since the fits would start only on the touch of the real witch. Such techniques could reveal impostures, but as late as the 1660s senior judges in England were rejecting these methods. The introduction of such methods corresponded with the disappearance of witches and the decline in witch-hunting. Wherever rationalists looked the evidence evaporated. No one could any longer muster enough faith to enjoy immunity from poisons or snake bites. Holy wafers no longer bled when they were stabbed; holy statues no longer bled when they were injured; bodies no longer bled in the presence of their murderers. Bibles burned just as well as heretical books. Those blessed by a visit from the Holy Spirit now spoke unintelligible garble instead of fluent foreign languages, and the flames above their heads were no longer visible.
