Lateral thinking is a term invented by Edward de Bono. He defines it as a technique of problem solving by approaching problems indirectly at diverse angles instead of concentrating on one approach at length. For example:

It took two hours for two men to dig a hole five feet deep. How deep would it have been if ten men had dug the hole for two hours?

Simplistically, the answer appears to be 25 feet deep. This is based on a few incorrect assumptions :

• Holes usually need to be deep as possible, rather than long or wide, as with a ditch.
• Ten men have just as much room to move around and shovel in (without getting in the way of other men) as two men do.
• Each of the ten men will work just as hard as the two men will—generally, the more people you have working on a project, the more each person will assume he can slack off and there's more people to talk to.

The correct answer—whatever it is—goes against standard mathematical training. This does not make it incorrect; standard mathematical training does not teach how to apply math to the real world very well, except with finances. Lateral thinking gets answers that are correct (or closer to the truth) because it takes into account more factors and the meanings of the words.

Example problems

• How long would it take to dig half a hole?
  • You can't dig half a hole.

• If one egg takes three minutes to boil, how long do two eggs cook?
  • About three minutes (the energy needed to get the eggs to boil is small in comparison to the energy needed to get the surrounding water to boil)

• If a knot in a 5-foot rope takes five minutes to undo, how long would a knot in a 10-foot rope take to undo?
  • Also five minutes (the length of rope usually has nothing to do with the complexity of the knot).

See also

• Creative problem solving
• Situation puzzle
• TRIZ
• Brainstorming

Further reading

• Edward De Bono, Lateral Thinking : Creativity Step by Step, Harper & Row, 1973, trade paperback, 300 pages, ISBN 0060903252