Even to this day, no native Australian animal species and only one plant species-the macadamia nut-have proved suitable for domestication. There still are no domestic kangaroos.

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?

He had quite liked the dwarfs. He often had no idea what they were talking about, but for a group of homicidal, class-obsessed small people, they were really rather good fun.

After a certain point, money is meaningless. It ceases to be the goal. The game is what counts.

Silene, who declines The garish noontide's blazing light; But when the evening crescent shines, Gives all her sweetness to the night.

I involve myself in an organisation called Tear Fund.

A thought embodied and embrained in fit words walks the earth a living being.

I don't think I'll get married again. I'm not looking for it. What I can say about my divorce and my failed engagement is that I learned where my bar is.

When you set aside the mantle of control in the painting process, images arise from ancient layers of the psyche.

Find yourself and express yourself in your own particular way. Express your love openly.

America is less safe today than it was the day that Barack Obama became president of the United States.

Give me something that'll haunt me when you're not around.