If your belief system is not founded in an objective reality, you should not be making decisions that affect other people.

Something we all have as kids and is beaten out of us as adults. Parents come up to me, "How do I get my kids interested in science?" They're already interested in science. Just stop beating it out of them.

When you're a hammer (as the saying goes), all your problems look like nails. If you're a meteorite expert pondering the sudden extinction of boatloads of species, you'll want to say an impact did it. If you're an igneous petrologist, volcanoes did it. If you're into spaceborne bioclouds, an interstellar virus did it. If you're a hypernova expert, gamma rays did it.

We should not measure our space-faring era by where footprints have been laid.... We should measure our era by how many people take no notice at all. A legacy rises to become culture only when its elements are so common that they no longer attract comment.

In whatever you choose to do, do it because it's hard, not because it's easy. Math and physics and astrophysics are hard. For every hard thing you accomplish, fewer other people are out there doing the same thing as you. That's what doing something hard means. And in the limit of this, everyone beats a path to your door because you're the only one around who understands the impossible concept or who solves the unsolvable problem.

We should not be ashamed of not having answers to all questions yet... I'm perfectly happy staring somebody in the face saying, 'I don't know yet, and we've got top people working on it.' The moment you feel compelled to provide an answer, then you're doing the same thing that the religious community does: providing answers to every possible question.

Kids should be allowed to break stuff more often. That's a consequence of exploration. Exploration is what you do when you don't know what you're doing.