“AIDS and malaria and TB are national security issues. A worldwide program to get a start on dealing with these issues would cost about USD25 billion... It's, what, a few months in Iraq.”

“All human societies go through fads in which they temporarily either adopt practices of little use or else abandon practices of considerable use.”

“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.”

“Australia is the most isolated continent.”

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

“Eurasia ended up with the most domesticated animal species in part because it's the world's largest land mass and offered the most wild species to begin with.”

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

“I'd rather spend my leisure time doing what some people call my work and I call my fun.”

“Infectious diseases introduced with Europeans, like smallpox and measles, spread from one Indian tribe to another, far in advance of Europeans themselves, and killed an estimated 95% of the New World's Indian population.”

“Introspection and preserved writings give us far more insight into the ways of past humans than we have into the ways of past dinosaurs. For that reason, I'm optimistic that we can eventually arrive at convincing explanations for these broadest patterns of human history.”

“It's striking that Native Americans evolved no devastating epidemic diseases to give to Europeans, in return for the many devastating epidemic diseases that Indians received from the Old World.”

“I've always been interested in a lot of things, and a lot of things at the same time, and I always tried to explain them to myself. I ask a lot of questions.”

“Lest those islands still seem to you too remote in space and time to be relevant to our modern societies, just think about the risks... of our increasing globalization and increasing worldwide economic interdependence.”

“Measles and TB evolved from diseases of our cattle, influenza from a disease of pigs, and smallpox possibly from a disease of camels. The Americas had very few native domesticated animal species from which humans could acquire such diseases.”

“Native Americans had only stone and wooden weapons and no animals that could be ridden. Those military advantages repeatedly enabled troops of a few dozen mounted Spaniards to defeat Indian armies numbering in the thousands.”

“No government is here forever. And there are other forces - the most potent force in our society, in fact, big business - doing good for the environment.”

“Starbucks goes to a great effort, and pays twice as much for its coffee as its competitors do, and is very careful to help coffee producers in developing countries grow coffee without pesticides and in ways that preserve forest structure.”

“Take air quality in the United States today: It's about 30 percent better than it was 25 years ago, even though there are now more people driving more cars.”

“Technology causes problems as well as solves problems. Nobody has figured out a way to ensure that, as of tomorrow, technology won't create problems. Technology simply means increased power, which is why we have the global problems we face today.”

“Technology has to be invented or adopted.”

“The United States has long thought of itself as the land of infinite plenty, and historically we did have abundant resources. But now we are gradually exhausting our fisheries, our topsoil, our water. On top of that, we're coming to the end of world resources.”

“Thousands of years ago, humans domesticated every possible large wild mammal species fulfilling all those criteria and worth domesticating, with the result that there have been no valuable additions of domestic animals in recent times, despite the efforts of modern science.”

“Twenty years ago, you might have been pessimistic and said there's no hope. But these days, some of our very biggest companies are acting remarkably cleanly. And in some cases, although not all cases, the CEOs are the driving forces behind that.”

“We can't manipulate some stars while maintaining other stars as controls; we can't start and stop ice ages, and we can't experiment with designing and evolving dinosaurs.”

“We study the injustices of history for the same reason that we study genocide, and for the same reason that psychologists study the minds of murderers and rapists... to understand how those evil things came about.”

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