One's visual memory or imagination.
The concept of us having an 'eye in our mind' is ancient and dates back to at least the 14th century, when Chaucer used it in The Man of Law's Tale, circa 1390:
"It were with thilke eyen of his mynde, With whiche men seen, after that they been blynde."
The first actual mention of mind's eye comes in 1577 when Hubert Languet used it in a letter. This was subsequently printed in The Correspondence of Sir Philip Sidney and Hubert Languet, 1845:
"What will not these golden mountains effect ... which I dare say stand before your mind's eye day and night?"
The term probably became known through the work of Shakespeare. He uses it in the best-known of all plays - Hamlet, 1603, in a scene where Hamlet is recalling his father:
Thrift, thrift, Horatio! the funeral baked meats
Did coldly furnish forth the marriage tables.
Would I had met my dearest foe in heaven
Or ever I had seen that day, Horatio!
My father! - methinks I see my father.
Where, my lord?
In my mind's eye, Horatio.
- Copyright © Gary Martin, 1996 - 2009