The Three Wise Monkeys

I'm sure most of you have seen the image: three monkeys sitting in line, one of them covering its ears, another its eyes and the other its mouth. It's a very common picture, but do we know what it means?
The three wise monkeys are a pictorial representation. Together they embody the principle to "see no evil, hear no evil, speak no evil". The three monkeys are Mizaru, covering his eyes, who sees no evil; Kikazaru, covering his ears, who hears no evil; and Iwazaru, covering his mouth, who speaks no evil. Sometimes there is a fourth monkey depicted with the three others; the last one, Shizaru, symbolizes the principle of "do no evil". He may be shown covering his abdomen or genital area, or crossing his arms.
The proverb has different meanings, with associations of being good of mind, speech and actions. However, in the western world the proverb is often used to describe someone who looks the other way when they see something illegal or inappropriate.
The oldest reference to the proverb is in the Analects of Confucius, in China: "Look not at what is contrary to propriety; listen not to what is contrary to propriety; speak not what is contrary to propriety; make no movement which is contrary to propriety". Probably, the phrase was shortened after its introduction to Japan, where the most famous representation is found in a carving over the door of the famous Tosho-gu shrine.
But, why the monkeys? The concept of monkeys originated from wordplay: The saying in Japanese is "mizaru, kikazaru, iwazaru", employing the archaic Japanese form "zaru" for negatives. The pronunciation of "zaru" is the same as one of the readings ("saru") of the Japanese kanji for monkey.
Out of curiosity, Mahatma Ghandi's one notable exception to his lifestyle of non-possession was a small statue of the three monkeys.
This post was originally Alan's idea.