And as in the Dark all Cats are grey, the Pleasure of Corporal Enjoyment with an old Woman is at least equal and frequently superior; every Knack being by Practice capable of improvement.
- Benjamin Franklin, letter, 1745
Some 500 years ago, John Heywood observed that "When all candles bee out, all cats be gray." (Proverbes, Pt. 1 Ch. 5.) Heywood's younger contemporary, Miguel de Cervantes Saavedra, echoed the sentiment in Don Quixote, Pt. 2 Ch. 33 - "In the night, all cats are gray". Presumably, Heywood saw fit to record it because it was an aphorism in common circulation at the time; and indeed, there are much older German and Latin sayings of similar meaning, warning against confusing superficial details with essential qualities.