I set before you two ways: You can use your technology to destroy yourselves or to carry you to the planets and the stars. It's up to you.

When permitted to listen to alternative opinions and engage in substantive debate, people have been known to change their minds. It can happen.

There are many hypotheses in physics of almost comparable brillance and elegance that have been rejected because they did not survive such a confrontation with experiment. In my view, the human condition would be greatly improved if such confrontations and willingness to reject hypotheses were a regular part of our social, political, economic, religious and cultural lives.

Even Johannes Kepler, Isaac Newton, Charles Darwin, Gregor Mendel, and Albert Einstein made serious mistakes. But the scientific enterprise arranges things so that teamwork prevails: What one of us, even the most brilliant among us, misses, another of us, even someone much less celebrated and capable, may detect and rectify.

Chlorine is a deadly poison gas employed on European battlefields in World War I. Sodium is a corrosive metal which burns upon contact with water. Together they make a placid and unpoisonous material, table salt. Why each of these substances has the properties it does is a subject called chemistry.

My long-time view about Christianity is that it represents an amalgam of two seemingly immiscible parts-the religion of Jesus and the religion of Paul. Thomas Jefferson attempted to excise the Pauline parts of the New Testament. There wasn't much left when he was done, but it was an inspiring document.

Writing a novel is like trying to solve a very long mathematical equation. Changing anything can change everything else.