The universe is not required to be in perfect harmony with human ambition.

The significance of our lives and our fragile planet is then determined only by our own wisdom and courage. We are the custodians of life's meaning. We long for a Parent to care for us, to forgive us our errors, to save us from our childish mistakes. But knowledge is preferable to ignorance. Better by far to embrace the hard truth than a reassuring fable. If we crave some cosmic purpose, then let us find ourselves a worthy goal.

The method of science, as stodgy and grumpy as it may seem, is far more important than the findings of science.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

we make our world significant by the courage of our questions and the depth of our answers

Some 5 billion years from now, there will be a last perfect day on Earth... then the sun will begin to die, life will be extinguished, the oceans will boil and evaporate away.

The universe forces those who live in it to understand it.