Lately a lot of people have been questioning why humans didn't get together sooner and start a civilization. I have countered this by asking why African tribes haven't independently invented a microwave. I think both of these questions, when seriously pondered, reveal their own answer.
My hypothesis is this:
Imagine thousands of human tribes scattered all over the earth. Each speaks a different language and keeps to itself. Now imagine one "tribe" which can communicate easily within itself, with all people intermingling and exchanging information. Which one is better?
The latter. Think about someone like Thomas Edison, Galileo, or Stephen Hawking. The entire Universal "tribe" benefits from those very, very rare geniuses who come along and share their insight with the rest of us. Instead of a single, small tribe gaining their insight (and possibly losing it or not recognizing its worth!), everyone can benefit. We benefit from countless intellectuals who would belong to another "tribe" if we were more divided.This brings me to the origins of civilization: What happened to us, when we were living in small tribes that made us settle down and begin agriculture? I suggest that primitive tribes had to "wait" - for lack of a better word- for someone who thought indepently enough, could organize others well enough, and was viewed as powerful enough within the tribe to persuade others to settle down for a life of agriculture. Even then there were no guarantees: Several of these proto-farming tribes may have started up and gone extinct before one managed to stay around.
Once the right one managed to survive and handle itself, the intellectual abilities of the tribe grew by leaps and bounds. The population grew, and every generation or two someone would be born who could teach the tribe something; a slightly more complex form of language or a new farming technique, for instance.
This affect is what is responsible for the dramatic boom in technology and science we have seen over the past few hundred years. Two British scientists discovered the key to life, DNA, and shared it with Americans, Russians, Germans, and etc. Thomas Edison invented the lightbulb, among other ingenius inventions, and shared this information with the rest of the world.
That's my hypothesis.