The message from history is so blatantly obvious - that free trade causes mutual prosperity while protectionism causes poverty - that it seems incredible that anybody ever thinks otherwise. There is not a single example of a country opening its borders to trade and ending up poorer.

A true scientist is bored by knowledge; it is the assault on ignorance that motivates him - the mysteries that previous discoveries have revealed.

Society works not because we have consciously invented it, but because it is an ancient product of our evolved predispositions. It is literally in our nature.

You need to understand how human beings bring together their brains and enable their ideas to combine and recombine, to meet and, indeed, to mate. In other words, you need to understand how ideas have sex.

It is the assumption of this book that there is a typical human nature. It is the aim of this book to seek it. Just like a surgeon, a psychiatrist can make all sorts of basic assumptions when a patient lies down upon the couch. He can assume that the patient knows what it means to love, to envy, to trust, to think, to speak, to fear, to smile, to bargain, to covet, to dream, to remember, to sing, to quarrel, to lie. The 'smile' of a baboon is a threat; the smile of a man is a sign of pleasure: it is human nature, the world over.

Our minds have been built by selfish genes, but they have been built to be social, trustworthy and cooperative.

The genome is a book that wrote itself, continually adding, deleting and amending over four billion years.