You can predict the weather for the day after tomorrow. Stretch that to a week, and your prediction always departs from reality. The implication was staggering. We've always presumed that if you barely change a cause, you'll barely change the effect. Suddenly, Lorenz saw that the weather would change utterly if you started things out just a little differently.
Weather obeys physical laws.
But if you change one breath of air, those laws will spin out in a wholly different story. Meteorologists began talking about something they called the Butterfly Effect . The idea was that if a butterfly chances to flap his wings in Beijing in March, then, by August, hurricane patterns in the Atlantic will be completely different. Not long after that day in 1960, the scientific world began changing. Perhaps all kinds of nasty problems we can't solve are nasty just because we can never state them accurately enough.