Acquaintances represent a source of social power, and the more acquaintances you have the more powerful you are.

The Rule of 150 says that congregants of a rapidly expanding church, or the members of a social club, or anyone in a group activity banking on the epidemic spread of shared ideals needs to be particularly cognizant of the perils of the bigness. Crossing the 150 line is a small change that can make a big difference.

People at CDC [Centers for Disease Control] who cut their teeth on diseases over the last 10 years have started to think of crime as another disease, and using some of these same concepts. It was something that was in the air in that world, but it was time to bust it out and apply it to any number of different social epidemics.

I should point out that I have a picture of Asbel Kiprop as the screensaver on my phone. Is that embarrassing?

Policy is driven by more than politics, however. It is equally driven by ideas.

...mediocre people find their way into positions of authority...because when it comes to even the most important positions, our selection decisions are a good deal less rational than we think.

Sometimes the most modest changes can bring about enormous effects.