African cavalry mounted on rhinos or hippos would have made mincemeat of European cavalry mounted on horses. But it couldnt happen.

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?

Streams of consequence flow from every action, and from every conflict there are two paths by which events may go.

The strongest bank in the United States will last only so long as the people will have sufficient confidence in it to keep their money there.

The possessors of wealth can scarcely be indifferent to processes which, nearly or remotely have been the fertile source of their possessions.

I know of no better thermometer to your spiritual temperature than this, the measure of the intensity of your prayer.

We only did probably two, three takes on every scene we did, at the most.

Logic cannot comprehend love; so much the worse for logic.

Oh, my bad ... I'm sorry for bothering you. I forgot I only exist when you need me for something.

The best way to escape your problem is to solve it.

... freedom isn't the absence of boundaries; it's the ability to operate successfully and happily within boundaries.

I know you won't believe me, but the highest form of Human Excellence is to question oneself and others.