Blind men and an elephant

The Blind men and an elephant is an idiom.
The story of the blind men and an elephant comes from India. It is about a range of truths and mistakes. It is also about the need for communication and the need for respect for different perspectives. 
The idiom shows the effects of observation and bias. Idioms are a common stumbling block for learners of a language.
Story.
A group of blind men (or men in the dark) touch an elephant to learn what it is like. Each one feels a different part, but only one part. For example, one touches only the side and another touches only the tusk. 
The blind men discover that they disagree when each describes what he has learned from touching the elephant.
Poem.
A famous poem — "The Blind Men and the Elephant" by John Godfrey Saxe (1816–1887).
The poem begins:
It was six men of Indostan
To learning much inclined,
Who went to see the Elephant
(Though all of them were blind),
That each by observation
Might satisfy his mind
They conclude that the elephant is like a wall, snake, spear, tree, fan or rope, depending upon where they touch. None of blind men's description is correct for the whole elephant.