In all mammalian species that have so far been carefully studied, the rate at which their members engage in the killing of conspecifics is several thousand times greater than the highest homicide rate in any American city.

Darwin's idea of natural selection makes people uncomfortable because it reverses the direction of tradition.

I think that there are no forces on this planet more dangerous to us all than the fanaticisms of fundamentalism, of all the species: Protestantism, Catholicism, Judaism, Islam, Hinduism, and Buddhism, as well as countless smaller infections. Is there a conflict between science and religion here? There most certainly is.

I listen to all these complaints about rudeness and intemperateness, and the opinion that I come to is that there is no polite way of asking somebody: have you considered the possibility that your entire life has been devoted to a delusion? But that’s a good question to ask. Of course we should ask that question and of course it’s going to offend people. Tough.

Not a single one of the cells that compose you knows who you are, or cares.

Those who feel guilty contemplating "betraying" the tradition they love by acknowledging their disapproval of elements within it should reflect on the fact that the very tradition to which they are so loyal—the "eternal" tradition introduced to them in their youth—is in fact the evolved product of many adjustments firmly but delicately made by earlier lovers of the same tradition.

The chief trick to making good mistakes is not to hide them - especially not from yourself. Instead of turning away in denial when you make a mistake, you should become a connoisseur of your own mistakes, turning them over in your mind as if they were works of art, which in a way they are.