The psychologist Ray Hyman says that, even if the results from remote viewing experiments were reproduced under specified conditions, they would still not be a conclusive demonstration of the existence of psychic functioning. He blames this on the reliance on a negative outcome—the claims on ESP are based on the results of experiments not being explained by normal means. He says that the experiments lack a positive theory that guides as to what to control on them and what to ignore, and that "Parapsychologists have not come close to (having a positive theory) as yet".