An eidolon can be a ghost, or some sort of insubstantial apparition.
If you don't happen to have a ghost handy then a reflection in a shop window might be the easiest way to spot one of these.
Photo by Eugène Atget
Much easier, though, is the sort of eidolon which is an ideal or idealised figure. These are everywhere.
In fashion plates:
And, of course, if all else fails there's always Barbie:
Does the use of these idealised images make the rest of us feel inadequate?
...well, no more than usual, I'd say.
Actually, you know something? If anything, they might even give us hope.
Spot the Frippet: eidolon. This word is the Greek for phantom or idol.