"Consider throwing dice. One individual die is unpredictable. It could be a 1, or a 3, or a 6, who knows? But when you throw millions of dice, you can confidently predict that the average will be 3.5. So the Correspondence Principle says that classical Physics worked, because it was always dealing with aggregate properties of large numbers of particles (photons, dice) and could make correct predictions. But those predictions and theories don't apply at all to individual particles which may follow very different rules."
The last line sound familiar?