One day, back when I was a schoolboy, I got stuck with a particularly tricky programming problem. After unsuccessfully puzzling over the problem I decided to take a break and went for a walk with my family.

About an hour later, while chatting about something else entirely, I was suddenly struck by the solution – it just popped into my head. It was an excellent example of the subconscious mind ticking away at a problem.

Since then I have often wondered at how solutions seem to just pop into my mind. When trying to solve a tricky problem or brain-teaser the solution suddenly appears – but from where?

Sometimes I can follow my conscious thought process systematically arriving at a solution – but often it just pops into my consciousness.

The Economist has this fascinating article about an experiment illustrating that the subconscious mind is responsible for at least some problem solving.

Experiment:
Experimental subjects were faced with a brain-teaser had their brains scanned while they attempted to solve the problem.

Results:
Several seconds (up to eight) before a subject had a eureka moment his/her brain waves altered significantly.

Interpretation:
This seems to show that the test subjects had subconsciously solved the problem several seconds before they consciously realized that they had the solution.

We are hopelessly ignorant of the workings of human consciousness. I truly hope that during my lifetime experiments such as this one will reveal this fascinating miracle.