The greatest of all the accomplishments of 20th century science has been the discovery of human ignorance

Doctors, dressed up in one professional costume or another, have been in busy practice since the earliest records of every culture on earth. It is hard to think of a more dependable or enduring occupation, harder still to imagine any future events leading to its extinction.

It would seem to me... an offense against nature, for us to come on the same scene endowed as we are with the curiosity, filled to overbrimming as we are with questions, and naturally talented as we are for the asking of clear questions, and then for us to do nothing about, or worse, to try to suppress the questions.

The human brain is the most public organ on the face of the earth, open to everything, sending out messages to everything. To be sure, it is hidden away in bone and conducts internal affairs in secrecy, but virtually all the business is the direct result of thinking that has already occurred in other minds.

I won't compare ants and people, but ants give us a useful model of how single members of a community can become so organized that they end up resembling, in effect, one big collective brain. Our own exploding population and communication technology are leading us that way.

As evolutionary time is measured, we have only just turned up and have hardly had time to catch breath, still marveling at our thumbs, still learning to use the brand-new gift of language. Being so young, we can be excused all sorts of folly and can permit ourselves the hope that someday, as a species, we will begin to grow up.

I can say, if I like, that social insects behave like the working parts of an immense central nervous system: the termite colony is an enormous brain on millions of legs; the individual termite is a mobile neurone.