Jesus' Resurrection Appearances Were Just Hallucinations
According to this argument the claims that Jesus appeared to his disciples two days after his death were an example of hallucinations that are quite common when people are grieving the death of a loved one. In their grief, family members and friends of the deceased may "see" the dead person appearing like a ghost in his/her familiar surroundings.
Most scholars agree that the resurrection appearances of Jesus just do not fit this type of psychiatric phenomenon. He is specifically described as asking disciples for a fish supper to prove the reality of his risen body.
There have been well documented instances of 'mass hallucinations' , such as the mass sighting of a vision of the Virgin Mary by pilgrims to her shrine at Medugorije, Slovakia. But these are of a different order from the reports in the gospels and in Paul's letter.