Ray Hyman discovered many methodological errors with Schwartz's research including; "Inappropriate control comparisons", "Failure to use double-blind procedures", "Creating non-falsifiable outcomes by reinterpreting failures as successes" and "Failure to independently check on facts the sitters endorsed as true". Hyman wrote "Even if the research program were not compromised by these defects, the claims being made would require replication by independent investigators." Hyman criticizes Schwartz's decision to publish his results without gathering "evidence for their hypothesis that would meet generally accepted scientific criteria... they have lost credibility."
Not everyone loves talking on the phone, and sometimes it’s just impractical: when you’re at work or in a public place, when you don’t want to be overheard, when you don’t want to take notes while you are getting your reading. Connecting with a psychic online can feel different from connecting over the phone. For some, it feels easier to initiate the first conversation using a familiar texting interface. You don’t connect through your voices, yet exchanging messages in real time can be very intimate and revealing.
In 1917, Edward Clodd analyzed the mediumship of the trance medium Gladys Osborne Leonard and came to the conclusion that Leonard had known her séance sitters before she had held the séances, and could have easily obtained such information by natural means. The British psychiatrist Charles Arthur Mercier wrote in his book Spiritualism and Sir Oliver Lodge (1917) that Oliver Lodge had been duped into believing mediumship by trickery and his spiritualist views were based on assumptions and not scientific evidence.
Senses used by mental mediums are sometimes defined differently from in other paranormal fields. A medium is said to have psychic abilities but not all psychics function as mediums. The term clairvoyance, for instance, may include seeing spirit and visions instilled by the spirit world. The Parapsychological Association defines "clairvoyance" as information derived directly from an external physical source.