Suppose that 100 million Americans are each given $100 and needs to decide whether to:

- Buy a pair of jeans, or
- Contribute $100 to a system protecting earth from collisions with asteroids.

(These are the only two options as far as spending these $100.)

The probability that an asteroid is deflected is equal to the proportion of these 100 million Americans who decide to give $100 toward asteroid protection.

Suppose that each of the 100 million Americans attaches a value of $1 to an increase of 1% in the chance of asteroid deflection.

Also suppose that each each of the 100 million Americans attaches a value of $100 to the pair of jeans they could buy instead of giving to asteroid protection.