Scrying

Scrying (also known by various names such as "seeing" or "peeping") is the practice of looking into a suitable medium in the hope of detecting significant messages or visions. The objective might be personal guidance, prophecy, revelation, or inspiration, but down the ages, scrying in various forms also has been a prominent means of divination or fortune-telling. It remains popular in occult circles, discussed in many websites and books, both modern and centuries old.
In various sources such as dictionaries, scrying often is described as crystal gazing, but in fact the media, terminologies, and methods of different practitioners vary arbitrarily and need not involve crystals or glassy materials at all.

As is true of other media or forms of divination and occult practices, advocates assert that scrying has merit as a means of revealing the future or other unknowns; such assertions however, lack support from any form of falsifiable scientific investigation.

There is no definitive distinction between scrying and other aids to clairvoyance, augury, or divination, but roughly speaking, scrying depends on fancied impressions of visions in the medium of choice. Ideally in this respect it differs from augury, which relies on interpretations of objectively observable objects or events (such as flight of birds); from divination, which depends on standardized processes or rituals; from oneiromancy, which depends on the interpretation of dreams; from the physiological effects of psychoactive drugs; and from clairvoyance, which notionally does not depend on objective sensory stimuli. Clairvoyance in other words, is regarded as amounting in essence to extrasensory perception.

Scrying is neither a single, clearly-defined, nor formal discipline and there is no uniformity in the procedures, which repeatedly and independently have been reinvented or elaborated in many ages and regions. Furthermore, practitioners and authors coin terminology so arbitrarily, and often artificially, that no one system of nomenclature can be taken as authoritative and definitive. Commonly terms in use are Latinisations or of descriptions of the media or activities. Examples of names coined for crystal gazing include crystallomancy, spheromancy, and catoptromancy. As an example of the looseness of such terms, catoptromancy should refer more specifically to scrying by use of mirrors or other reflective objects rather than by crystal gazing. Other names that have been coined for the use of various scrying media include anthracomancy for glowing coals, turifumy for scrying into smoke, and hydromancy for scrying into water. There is no clear limit to the coining and application of such terms and media.

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Wikipedia