This is Hidden Brain, I'm Shankar Vedanta.

Two thousand years ago, in ancient Greece, a local ruler had a problem.

He suspected his new crown was not made of solid gold, but he couldn't prove it.

So he asked the Kingdom's most famous mathematician Archimedes to investigate.

While pondering this puzzle, Archimedes took a bath.

He filled the tap to the brim, and as he stepped in, the water overflowed.

Archimedes had a flash of insight.

The water that spilled out of the bath reflected the volume of his own body.

He realized that if he put the crown into water, he could measure its volume by seeing how much water was displaced.

He could use this to tell the difference between a crown made of pure gold and one that had impurities.

He was so excited with his discovery that he leaped out of the tub and ran naked through the streets, shouting,

�Urika, Urika, which is Greek for, I found it. I found it.�

The famous story of the Urika moment may or may not have happened.

It was written 200 years after Archimedes died, but it says something profound about our minds.

A good explanation gives us pleasure.

And when we can't come up with a good explanation, we feel dissatisfied.

Something in the human mind yearns to make sense of the world.

Some researchers think this sense-making drive is a basic human impulse, no different than thirst or hunger.

This week on Hidden Brain, we begin a three-part series about our need to explain the world

and how the stories we tell ourselves can lead to discovery, delight, and disaster.

Why is my friend late? How does nuclear fission work?

What exactly is happening when I sneeze?

...