Questioning Assumptions
Hidden assumptions can block a solution. In the elevator puzzle, the unexpected explanation depends on which floor buttons the man can reach.
THE IDEA
Problem
A man worked in a tall office building. Each morning he got in the lift on the ground floor, pressed the lift button to the tenth floor, got out of the lift and walked up to the fifteenth floor. At night he would get into the lift on the fifteenth floor and get out again on the ground floor. What was the man up to?
Various explanations are offered. They include:
- The man wanted exercise.
- He wanted to talk to someone on the way up from the tenth to the fifteenth floor.
- He wanted to admire the view as he walked up.
- He wanted people to think he worked on the tenth floor (it might have been more prestigious) etc.
In fact the man acted in this peculiar way because he had no choice. He was a dwarf and could not reach higher than the tenth floor button.
The puzzle invites the assumption that the man can reach any floor button, leaving his behavior as the apparent mystery.
One can generate other problems of this sort. One can also collect examples of behaviour which seem bizarre until one knows the real reason behind it. The purpose of these problems is just to show that the acceptance of assumptions may make it difficult or impossible to solve a problem.
2. The block problems
The block problems introduced by this heading are not included in the excerpt.
When to use it
When troubleshooting a technical issue, list all assumptions and test each one.
In a business meeting, challenge common assumptions about customer behavior.
When solving a puzzle or riddle, explicitly state the assumptions before seeking a solution.
During creative brainstorming, ask 'What if the opposite of this assumption were true?'
FROM THEORY TO EVERYDAY LIFE
In practice
The Dwarf in the Elevator
A man rides the elevator to the tenth floor each morning and walks up five flights, then rides down from the fifteenth floor at night. Observers assume normal height; the real reason is the man is a dwarf who cannot reach the button for higher floors.
A MOMENT TO REFLECT
Put it to work.
What assumptions am I currently making about this problem that might be false?
How would the solution change if I questioned a key assumption?
Can I list three hidden assumptions in a recent decision I made?
CONTINUE THE CONVERSATION
Source texts
- Lateral Thinking A Textbook of Creativity (Edward de Bono)