A psychological term this, but taken from a dictionary of words, not of psychology, so I probably won’t give it the full array of detail that a psychologist attaches to the word.
Eidetic
is an adjective referring to a mental image, and means “extraordinarily clear and vivid, as though actually visible”. It can also be applied, both as an adjective and as a noun, to a person “able to reproduce a vividly clear visual image of what has been seen previously”.
The root, as you might expect from the first two letters, is Greek: eidos, “form”, from ideis, “to see”; eidetikos, “belonging to an image”.
There are two other words connected with eidos.
An eidograph is an instrument for copying drawings. The one in the photo has the caption “Wallace’s Eidograph made by James White a famous Glasgow instrument maker.The eidograph was an improved version of the simple pantograph which was invented in 1821 by William Wallace, Professor of Mathematics at Edinburgh University. It can be used to copy, enlarge or reduce drawings. This is an immaculate example of this instrument, the best I’ve ever seen. It was sold to the firm of Macfarlane, Brown & Boyd in Scotland from whom it was acquired by a collector many years ago. James White worked under his own name from 1860, this instrument probably dates from the 1880s.” (It’s already been sold, I’m afraid.)
Photo from http://www.earlytech.com/shop/view_item/2143327242
You can see the drawing points at the bottom of the right arm and the top of the left arm. You traced the original picture with one point and the other point (or pencil in later versions) drew a replica. You can still buy pantographs in the sort of catalogues that arrive in droves around Christmas filled with educational toys; I always wanted one because I’m hopeless at drawing! They must have been very useful for copying plans and things in the days before photocopiers.
An eidolon is “a phantom or apparition; a confusing reflection or reflected image; an ideal or idealised person or thing”. That’s unexpected when you compare it with “eidetic”, where the image is clear and vivid; where did the confusion appear from, and why – and how? Chambers Dictionary is silent on the change, though it does say that Greek eidos became idolum in Latin before appearing in English as “idol”, which is an alternative spelling for eidolon (so if you weren’t sure how to pronounce it before, it’s “idol-on”).
Clear as mud? I hope so! Either way, I’d love to hear from you, so please do comment below.
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