The Drinking Principle is the easiest possible form of social control

So, you've decided to be an evil puppet-master. That makes sense, you seem like the type. If you want to turn your fellow human beings into automatons following your direction, all you have to do is scoot over to a bar. Then you need to apply the Drinking Principle.

The Drinking Principle is stated this way — there is someone in a bar that, if he or she is drinking, then everyone is drinking. The words make it sound like a form of social manipulation, but it's just a logical principle. If everyone in the bar is drinking, then you can pick one person, any person, as the designated drinker. If that person is drinking, then everyone is drinking. If, on the other hand, one person is not drinking, then they are the non-drinker. If that person then starts drinking, then everyone is drinking.

It's a facile statement, but it can be expanded. It was created by Raymond Smullyan, who came up with the "One of us always tells the truth and one of us always lies," logical puzzle that was shown in the movie Labyrinth. He liked the fact that it seemed to imply a cause and effect, when actually it is just coincidence.

Smullyan extended the Drinking Principle outward, and took it to extremes. For example, he said that there is one person of each sex in the world who, if they become unable to have children, the entire human race will end. The implication is, if those two become sterile, they will somehow affect everyone else.

In fact, the logic goes the other way. As long as one person of each sex can still have children, there is a chance for the human race to continue — even if that chance relies heavily on the tropes that V.C. Andrews liked to dabble in. However, if everyone else already can't have children, and either of those two go sterile, that's it for humanity. The trick is designating those two as the last to go — and then only mentioning them.

[Via What is the Name of This Book.]