IOU - Understanding the Whole

This is a famous and well known story but I don't mind repeating it with a question at the end.

Four blind men went to the zoo and visited the elephant. One blind man touched its side and said, ‘The elephant is like a wall.’ The next blind man touched its trunk and said, ‘The elephant is like a snake.’ The next blind man touched its leg and said, ‘The elephant is like a column.’ The last blind man touched its tail and said, ‘The elephant is like a broom.’ Then the four blind men started to fight, each one believing that his opinion was the right one. Each only understood the part he had touched; none of them understood the whole.

Question: How can one understand the whole?