Technology has to be invented or adopted.

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.

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?

Much of human history has consisted of unequal conflicts between the haves and the have-nots.

One of the surest ways to give up on your goals, is to chase them all at once.

He will use you to accomplish great things on the condition that you believe much more in His love than in your weakness.

Understanding was coming so fast, it seemed to bypass thought.

No past is dead for us but only sleeping love.

But something's missing.

I work with nature, although in completely new terms.

Let the wise guard their thoughts, which are difficult to perceive, extremely subtle, and wander at will. Thought which is well guarded is the bearer of happiness.

God is the true realistic point where human reason mostly, if not completely, breaks down.

The good Shepherd dog knows his master almost better than himself and must wonder indeed at the lack of the reverse.

I do think that given my background as a poet, and also I work in a different field, you're sort of neither here nor there.