You can never know if a person forgives you when you wrong them. Therefore it is existentially important to you. It is a question you are intensely concerned with. Neither can you know whether a person loves you. It’s something you just have to believe or hope. But these things are more important to you than the fact that the sum of the angles in a triangle is 180 degrees. You don't think about the law of cause and effect or about modes of perception when you are in the middle of your first kiss.

If there is a god, he is not only a wizard at leaving clues behind. More than anything, he's a master of concealment. And the world is not something that gives itself away. The heavens still keep their secrets. There is little gossip amongst the stars. But no one has forgotten the Big Bang yet. Since then, silence has reigned supreme, and every thing there is moving away. One can still come across a moon. Or a comet. Just don't expect friendly greetings. No visiting cards are printed in space.

A state that does not educate and train women is like a man who only trains his right arm.

It is by no means certain that we advance our philosophical quest by reading Plato or Aristotle. It may increase our knowledge of history but not of the world.

You might say that the very best that can happen is to have energetic opponents.

We are the living planet!

When we gaze at a star in the Milky Way which is 50,000 light-years away from our sun, we are looking back 50,000 years in time." "The idea is much too big for my little head." "The only way we can look out into space, then, is to look back in time. We can never know what the universe is like now. We only know what it was like then. When we look up at a star that is thousands of light-years away, we are really traveling thousands of years back in the history of space.