The Anasazi did manage to construct in stone the largest and tallest buildings erected in North America until the Chicago steel girder skyscrapers of the 1880s.

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?

It's Painful Experiences... That Makes You Wise!

It was a dreadful thing to see. Humans beings can be awful cruel to one another.

I'm too awkward to date, I think. I'm kind of all or nothing, you know? Either put a baby inside of me or leave me alone.

Most of the programmers in ten years will be us, and we won't get much smarter.

We should be shining lamps, giving light to all around us.

The machine does not control the mind of man, though it affects the mind of man; it is the mind of man that can and should control the machine.

Shame doesn't exist in the animal kingdom. It's a human conception.

My husband melted my heart the day he asked me, "Can I participate in your wonder?" In whose wonder do you get to participate today?

Wherever we go, across the Pacific or Atlantic, we meet, not similarity so much as 'the bizarre'. Things astonish us, when we travel, that surprise nobody else

You may have won the war, but you will never take my crown