Perhaps we’ve never been visited by aliens because they have looked upon earth and decided there’s no sign of intelligent life.

I [do not know] when the end of science will come. ... What I do know is that our species is dumber than we normally admit to ourselves. This limit of our mental faculties, and not necessarily of science itself, ensures to me that we have only just begun to figure out the universe.

If you want to assert a truth, first make sure it's not just an opinion that you desperately want to be true.

I've always been interested in pop culture. Some of my colleagues think of pop culture as beneath them, or there's the ivory tower and then there's everybody else, and I never could buy into that wall that's been put up by so many people over the decades and even the centuries.

Dinosaurs are extinct today because they lacked opposable thumbs and the brainpower to build a space program.

Darwin's theory of evolution is a framework by which we understand the diversity of life on Earth. But there is no equation sitting there in Darwin's 'Origin of Species' that you apply and say, 'What is this species going to look like in 100 years or 1,000 years?' Biology isn't there yet with that kind of predictive precision.

We are not simply in the universe, we are part of it. We are born from it. One might even say we have been empowered by the universe to figure itself out - and we have only just begun.