One question is all that is needed to see if a clairvoyant is genuine. Or at least to see if they believe their skills are genuine. I will explain why no one can claim to know what the future holds while simultaneously maintaining their belief in free will. This extends to deities, psychics, cartomancers - anyone who claims they can accurately and precisely predict the future. Today I will focus on modern day snake oil salesmen - clairvoyants.