Any civilization that doesn't develop space travel dies.

If we can't think for ourselves, if we're unwilling to question authority, then we're just putty in the hands of those in power. But if the citizens are educated and form their own opinions, then those in power work for us. In every country, we should be teaching our children the scientific method and the reasons for a Bill of Rights. With it comes a certain decency, humility and community spirit. In the demon-haunted world that we inhabit by virtue of being human, this may be all that stands between us and the enveloping darkness.

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.

There are huge advertising budgets only when there's no difference between the products. If the products really were different, people would buy the one that's better. Advertising teaches people not to trust their judgment. Advertising teaches people to be stupid.

And after we returned to the savannahs and abandoned the trees, did we long for those great graceful leaps and ecstatic moments of weightlessness in the shafts of sunlight of the forest roof?

The Romans called the Christians atheists. Why? Well, the Christians had a god of sorts, but it wasn't a real god. They didn't believe in the divinity of apotheosized emperors or Olympian gods. They had a peculiar, different kind of god. So it was very easy to call people who believed in a different kind of god atheists. And that general sense that an atheist is anybody who doesn't believe exactly as I do prevails in our own time.

The well-meaning contention that all ideas have equal merit seems to me little different from the disastrous contention that no ideas have any merit.