But even these wild guesses cannot cover a dream which correctly reveals events of the future; events necessarily not known to any finite mind of the living or of the dead, and too full of detail for an explanation by aid of chance coincidence.
In face of these difficulties mankind has gone on believing in dreams of all three classes: dreams revealing the unknown present, the unknown past, and the unknown future.

The judicious reasonably set them all aside as the results of fortuitous coincidence, or revived recollection, or of the illusions of a false memory, or of imposture, conscious or unconscious.

However, the stories continue to be told, and our business is with the stories.
Taking, first, dreams of the unknown past, we find a large modern collection of these attributed to a lady named "Miss A---".

They were waking dreams representing obscure incidents of the past, and were later corroborated by records in books, newspapers and manuscripts.
But as these books and papers existed, and were known to exist, before the occurrence of the visions, it is obvious that the matter of the visions _may_ have been derived from the books and so forth, or at least, a sceptic will vastly prefer this explanation.

What we need is a dream or vision of the unknown past, corroborated by a document _not known to exist_ at the time when the vision took place and was recorded.