A Papua New Guinea health worker says the suggestion that sorcery is a creation of people's minds is simply untrue.
The comment was made during a conference in the Eastern Highlands provincial capital Goroka, which discussed the rising level of torture and murder of people suspected of using sorcery to cause illness and death.
Richard Kavare is a human rights officer with Laity Mobile Health Services, which flies vaccines and other essential medical supplies and services into remote areas.
He says he has evidence to disprove the assertion that sorcery is a concept people bring into their minds to make it happen.
"If you push a knife through a witch, it won't even hurt the witch. It will just bounce as though the knife is blunt. If you put an hot rod of iron into the witch body it won't even have any impact. It will just come out cold, freeze."
Richard Kavare says anyone who is injured in that way is not a witch.