If I don't make it, I'll be very sad that there are things I didn't do, but I'm happy that I've done what I have.

Death is the ultimate enemy - and I find nothing reproachable in those who rage mightily against the dying of the light.

Few tragedies can be more extensive than the stunting of life, few injustices deeper than the denial of an opportunity to strive or even to hope, by a limit imposed from without, but falsely identified as lying within.

In science, 'fact' can only mean 'confirmed to such a degree that it would be perverse to withhold provisional assent.' I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms.

What you see is that the most outstanding feature of life's history is a constant domination by bacteria.

I'm not a great deductive thinker, but I will admit to having competence in a very wide range of things - not being afraid to try to write about baseball, choral music and dinosaurs in the same week and see connections among them.

All evolutionary biologists know that variation itself is nature's only irreducible essence... I had to place myself amidst the variation.

We pass through this world but once.