We cannot agree with the idea that the late Edgar Cayce was a servant or prophet of God. For one thing, the doctrine of reincarnation which he espoused is contrary to the teachings of the Bible.
A more plausible explanation for the ability some have of viewing or remembering the past and looking into the future has to do with communication with evil spirits. Those spirits have been around throughout human history and are able to pass on the details of past events. They also have some knowledge of the future—though they often lie or are mistaken about many things (see, for example, I Timothy 4:1).
God's command is clear that we are not to be involved in any way with such spirits or those who consult them. The following verses show how strongly God warns against any contact with them: Leviticus 19:31; Deuteronomy 18:10-11; Isaiah 8:19-20.