PHANTASMS

A Phantasm is something apparently seen but having no physical reality; a phantom or an apparition.  Also could be considered an imaginative mental image. The word comes from phantom but deals with visual impressions alone.

Phantasmagoria is the art of creating supernatural illusions.

"Although the whole of this life were said to be nothing but a dream and the physical world nothing but a phantasm, I should call this dream or phantasm real enough, if, using reason well, we were never deceived by it." Gottfried Whilhem Leibniz, (1646-1716).