Faith healing refers to the healing of diseases, infirmities, etc., by supernatural means. In modern times, many Christian evangelists have claimed to have this ability. Some Christians have cited them as powerful evidence for the existence of God and the truth of Christianity. However, investigations of faith healers by men such as doctor William Nolen and magician James Randi have failed to find any evidence of actual miracles, and have turned up much evidence of fraud or, at best, self-deception.
"they shall lay hands on the sick, and they shall recover."
The methods by which faith healers convince others of their powers can be divided into two groups: those that do not require conscious trickery on the part of the healer and those that do.
In his investigation of Kathryn Kuhlman, Nolen came to the conclusion that she was probably sincere. His observations of her patients suggest a number of ways in which a healer could come to falsely believe in his or her powers:
- One man got up out of a wheelchair, but having met the man earlier, Nolen knew he had merely found walking difficult, not impossible. The man was back in his wheelchair after the service.
- One 20-year old girl came up on stage to claim a cure for polio, but as a doctor Nolen could see that she was obviously not cured. However, both Kuhlman and her audience seemed equally oblivious to this fact.
- Follow ups of patients with diseases that can improve naturally, such as multiple sclerosis, migraines, and bursitis resulted in patients claiming cures based on improvement but not total recovery, and even the extent of the improvement was unclear.
- Follow ups of patients who had claimed cures for cancer found that they all still had cancer afterwards, and in at least two cases the patient died shortly after visiting Kuhlman.
In summarizing his investigation, Nolen concluded:
- "The problem is, and I'm sorry this has to be so blunt, one of ignorance. Miss Kuhlman doesn't know the difference between psychogenic and organic diseases; she doesn't know anything about hypnotism and the power of suggestion; she doesn't know anything about the autonomic nervous system."
Thus, her lack of knowledge prevented her from accurately assessing what was going on in the people who came to her for help.
One of the main types of deception used by faith healers is faking miraculous knowledge of the ailments people come to them for. This can be done by having people write down their ailments on sealed slips whose contents are revealed using a standard magician's trick known as the "one ahead trick." It can also be done by having assistants pump clients for information, which the healer may then commit to memory, put into notes, or be delivered by a secret radio receiver. The latter was the method used by Peter Popoff, whom James Randi exposed by using an electronic eavesdropping system to record the radio messages. This recording was then played over a tape of one of Popoff's performances on Johnny Carson's Tonight Show.
Another common trick is known as leg-lengthening, where the healer claims the patient has one leg longer than the other and then purports to correct the problem right before the audience's eyes. To those not familiar with the trick, it can seem like an undeniable miracle, but it is in fact a variant of a standard carnival trick and is explained in great detail in James Randi's book The Faith Healers.
Healing of limb amputation
Many medical conditions, including death , are difficult to establish with absolute certainty. However, limb amputation is usually easy to confirm and a replacement limb never spontaneously regenerates in humans, according to current scientific understanding. Because of its unambiguity, limb amputation makes an excellent case study of miracle healing.
If miracle healing occurs, there is no reason they should not occur for amputated limbs. However, there is a conspicuous lack of evidence that miracle healing of missing limbs occurs. This suggests that healing miracles do not occur at all and their testimony is due to coincidences, hoaxes and self-delusion.
Apologists some times try to respond by substituting a question they think they can answer, such as the problem of evil. This is a red herring because the existence of evil is a separate question to healing miracles.
- "The ultimate question you’re really asking is Why Does God’s Creation Include Death and Suffering? "
They also claim God has performed greater miracles, which is also a red herring. Another line of counter argument is to cite Biblical healing Luke 22:51 , which is not a reliable source.  Other apologists argue that only Jesus and his close followers could perform this type of healing, which seems like an ad-hoc special pleading justification.  God is not bound by "spiritual gifts" being of limited time and can still answer prayers for healing, if he existed. Another approach is to argue that "God knows best" and does not heal people for their own good.
- "No, many times it is better that God wont heal the patient, He knows best. Many people have legs and destroy them for bad use. "
This argument might apply to individuals but at least some amputees would be better off not being amputees. This explanation fails to explain why there is a total lack of amputee healing miracles. Apologists also argue that healing miracles may occur but we just don't know about them.   This is unlikely because the incident would be very newsworthy and the story would spread widely. However, the lack of reliable testimony throughout history suggests this type of healing has never occurred.
- Nolen, William A. Healing: A Doctor In Search of a Miracle New York: Random House, 1974.
- Randi, James. The Faith Healers Prometheus Books, 1989.
- Huff Post, "Walter Williams Wakes Up In Body Bag At Morgue", 28th Feb 2014 
- Ray Comfort, "The Defender's Guide For Life's Toughest Questions", p. 19
- Why won't God heal amputees?, counter apologetics website, including the absence of miracle limb healing.