The single most important problem is our misguided focus on identifying the single most important problem!

History as well as life itself is complicated -- neither life nor history is an enterprise for those who seek simplicity and consistency.

Forced to choose between limiting population or trying to increase food production, we chose the latter and ended up with starvation, warfare, and tyranny.

The adoption of agriculture, supposedly our most decisive step toward a better life, was in many ways a catastrophe from which we have never recovered.

AIDS and malaria and TB are national security issues. A worldwide program to get a start on dealing with these issues would cost about $25 billion... It's, what, a few months in Iraq.

We're uncomfortable about considering history as a science. It's classified as a social science, which is considered not quite scientific.

Biology is the science. Evolution is the concept that makes biology unique.

Technology has to be invented or adopted.

Rhino-mounted Bantu shock troops could have overthrown the Roman Empire. It never happened.

Human societies vary in lots of independent factors affecting their openness to innovation.

Why did human development proceed at such different rates on different continents for the last 13,000 years?

I would look up at the moon and see that it was not the smooth orb we had all believed, but a pitted and scarred world with no air.

When we meet grace, it becomes the fuel of our faith. We pray, we read our Bibles, we worship and we live the purest lifestyle we can because we love a person.

The people who are doing the work are the moving force behind the Macintosh. My job is to create a space for them, to clear out the rest of the organization and keep it at bay.

Everything is in constant flux, from state to state, from good to bad and back again... only in transmutation, perpetual motion, lies truth.

I played three sports in high school, baseball, football and basketball. Baseball really helped me a lot.

I do think creating an open free-trade economy but with strong social support is the way to go.

I get a lot of questions about hair color. People are very into talking about hair.

We have to broaden our appeal to more customers than simply high-end customers. We have to understand that, in the aggregate, there are fewer customers out there, so we have to appeal to them all.

I don't care how hot a girl is - if she doesn't like animals, it would be a major, major problem.

It takes a long time to sound like yourself.