On Imaginary Apparitions

Johannes Müller's 1826 monograph, "On Imaginary Apparitions," proposes that the eye, as a sensory system, can be stimulated not only by external light but also by internal stimuli generated by the imagination. This theory suggests that individuals who report seeing visions, ghosts, or phantoms may be experiencing optical sensations that they believe originate externally, despite the absence of an adequate external stimulus. This concept relates to the broader topic of the paranormal, which encompasses experiences that seem unusual or unnatural and are often attributed to supernatural or folkloric origins. While science may not explain all such events, plausible explanations include the fallibility of human perception, the power of suggestion, and phenomena like sleep paralysis. An apparition is defined as the soul of a dead person appearing to living people, often referred to as a ghost or spirit.1234