Although native Africans domesticated some plants in the Sahel and in Ethiopia and in tropical West Africa, they acquired valuable domestic animals only later, from the north.

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?

Be what you yearn to be, and stop living for false ideals.

Paradise is exactly like where you are right now ... only much much better.

I shall not rest until every German sees that it is a shameful thing to be a lawyer.

What we're trying to do is address something I saw in Congress that was a major problem, which is to say that energy is arguably the most fundamental issue confronting our country.

May our nation continue to be the beakon of hope to the world.

To be impartial... is indeed to have taken sides already... with the status quo.

We must offer the world leadership designed to advance the goal of universal progress and enduring peace.

Every life lesson is on that baseball field.

I measure the amount of shows I should do by my hair. If my hair isn't good for campaigns and editorials, then obviously I am not going to look good.

My wife has her stuff and her taste, and I have my stuff and my taste.