There is no polite way to suggest to someone that they have devoted their life to a folly.

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.

In the beginning, there were no reasons; there were only causes. Nothing had a purpose, nothing has so much as a function; there was no teleology in the world at all.

We need to let our children grow up to face the world armed with knowledge, with much more knowledge than we ourselves had at their age. It is scary, but the alternative is worse.

Philosophers are never quite sure what they are talking about - about what the issues really are - and so often it takes them rather a long time to recognize that someone with a somewhat different approach (or destination, or starting point) is making a contribution.

To put it bluntly but fairly, anyone today who doubts that the variety of life on this planet was produced by a process of evolution is simply ignorant — inexcusably ignorant, in a world where three out of four people have learned to read and write.

The mind is the effect, not the cause.