Eratosthenes's only tools were sticks, eyes, feet, and brains; plus a zest for experiment. With those tools he correctly deduced the circumference of the Earth, to high precision, with an error of only a few percent. That's pretty good figuring for 2200 years ago.

A tiny blue dot set in a sunbeam. Here it is. That's where we live. That's home. We humans are one species and this is our world. It is our responsibility to cherish it. Of all the worlds in our solar system, the only one so far as we know, graced by life.

The cure for a fallacious argument is a better argument, not the suppression of ideas.

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.

While our behavior is still significantly controlled by our genetic inheritance, we have, through our brains, a much richer opportunity to blaze new behavioral and cultural pathways on short timescales.

Life is but a momentary glimpse of the wonder of this astonishing universe, and it is sad to see so many dreaming it away on spiritual fantasy.

We are star stuff harvesting sunlight.