to turn a blind eye to something: to disregard deliberately or pretend not to notice something of which one disapproves
This phrase is a shortening of to turn the deaf ear and the blind eye and variants, first recorded in A Discourse of Walking by Faith (London, 1698), by the philosopher and Church of England clergyman John Norris (1657-1712):
To be Crucify’d to the World, and to have the World Crucify’d to us; to be dead to its Pleasures, and insensible of its Charms, to turn the deaf Ear, and the blind Eye to all those Pomps and Vanities of the World which we renounc’d at our Baptism; and to have it no longer in our Hearts, but under our Feet.
In Family Secrets: Literary and Domestic (London, 1797), the writer and actor Samuel Jackson Pratt (1749-1814) makes Sir Armine extend the metaphor:
“Son, John,” said Sir Armine, “you should consider that the business of the drama, like that of life, cannot be carried on without sometimes putting in practice a temporary suspension of the faculties, both of ears and eyes. Upon that great stage, the stage of the world,” continued Sir Armine, “we are obliged to seem deprived of half our senses, in order to preserve any share of our good humour:—nay, we are frequently reduced to seem both deaf and blind to certain inconsistencies in others or in ourselves; and few are those who have not been under a necessity of turning the apparently deaf ear, and the blind eye, on our own conduct, or on that of our neighbours.”
This expression is still in usage. On 21st January 2016, The Chicago Tribune (Chicago, Illinois) reported that during the annual celebration of the Rev. Martin Luther King Jr. at Glencoes’ St. Paul AME Church,
St. Paul’s Rev. Norris Jackson, Jr., said people could not turn a “deaf ear or blind eye” to police brutality or unfair housing.
The earliest occurrence of the shortened form that I have found is from an article titled On the preservation of game during the winter, published in The New Sporting Magazine (London) of December 1832:
To acquire the good-will of the tenantry upon his estate is what every landlord is called upon to do by other and higher duties than the preservation of his game; but for this also it is essential. Colonel Hawker remarks how easy it is for a farmer, whilst walking over his grounds, to “put his foot upon a partridge’s nest,” if he be so inclined; and it is equally easy for him to turn a blind eye to the trespasser by day, or even to the poacher by night: a little kindness, however, prevents such things as these, for the English farmer would never think of them unless greatly enraged.
But to turn a blind eye existed earlier, since the British novelist Francis Lathom (1774-1832) punned on it in Men and Manners (London, 1800):
“Lady Gab was yesterday married to General Howitzer.”
“Gracious! you don’t say so? Why, he’s the very man for whom she had, her whole life, declared the greatest aversion.”
“Why,” replied Sir Harry, “the world is ill-natured enough to say, that as her ladyship and the general were engaged in a rubber, about three weeks ago, at the Viscountess of Loo’s, the general’s glass eye, by accident, fell upon the table—”
“Glass eye!” interrupted Lady Varny.
“I only speak from report,” returned he; “yes, a glass eye; and that her ladyship, who has an excellent taste for nic-nacories [= ?], was so charmed by its structure, that she immediately resolved on giving him her hand, for which he had long been a private suitor.”
“It is lucky for the poor man he has a blind eye to turn to her,” cried Lady Varny, “she paints like a sign-post;” straining a laugh which she could scarcely effect, owing to the plaister [sic] which confined the muscles of her own face.
The phrase to turn a blind eye is popularly attributed to an incident in the life of Horatio Nelson (1758-1805), who was blinded in the right eye in Corsica during the war with France. During the first battle of Copenhagen in 1801, when the admiral to whom Nelson was second in command signalled that he should leave off action, he reacted in the following manner, at least according to the English writer Robert Southey (1774-1843) in The Life of Horatio Lord Nelson (London, 1813):
“Leave off action? Now damn me if I do! You know, Foley,” turning to the captain, “I have only one eye,—I have a right to be blind sometimes:”—and then putting the glass to his blind eye, in that mood of mind which sports with bitterness, he exclaimed, “I really do not see the signal!”
Unfortunately for this traditional explanation, the battle took place after Francis Lathom had punned on the phrase in the above-mentioned passage from Men and Manners.