phantom

   The term phantom comes from the Greek noun phantasma, which means ghost or spectre. It was used in 1847 by the British surgeon Walter Cooper Dendy (1794-1871) as a synonym for the term ghost. Seeking to explain the perception ofphantoms by recourse to natural phenomena, Dendy draws up the following classification. Starting from two grand classes, i.e. "ghosts of the mind's eye, or phantasma", and ghosts of the eye, or optical illusion", he conceptualizes ghosts of the mind's eye as either * illusive perceptions (i.e. phantoms mediated by the mind's conversion of natural objects) or *illusive conceptions (i.e. phantoms mediated by the mind's own creation). The second class, ghosts of the eye, is conceptualized by him as being dependent on the laws which govern the material world" (i.e. atmospheric conditions, gases, lenses and mirrors, and diseases of the eye). Dendy's classification may be appreciated as a foreshadowing of the later division of *illusions into *cognitive illusions, * physiological illusions, and * physical illusions. A different use of the term phantom can be found in the work of the German psychiatrist Karl Ludwig Kahlbaum (1828-1899). In 1866 Kahlbaum used it to denote a *centripetal hallucination, i.e. a hallucination mediated primarily by the peripheral parts of the nervous system, and thus conceptualized as being dependent on objective, external stimuli. Kahlbaum divides the class of phantoms into three subclasses, comprising * stable hallucinations, *eretic hallucinations, and * functional hallucinations. The term phantom was used by him in opposition to the term *phantasma or *centrifugal hallucination. He considered both types of hallucination as variants of the overarching class of * direct hallucinations. A third usage of the term phantom is its employment as an abbreviation for the term * phantom limb illusion.

   References

   Dendy, W.C. (1847). The philosophy of mystery. New York, NY: Harper & Brothers.

   Kahlbaum, K. (1866). Die Sinnesdelirien. Allgemeine Zeitschrift für Psychiatrie und psychischgerichtliche Medizin, 23, 56-78.