A scientist's life, the author says, is indeed conflictual, formed by battles, defeats, and victories: but the adversary is always and only the unknown, the problem to be solved, the mystery to be clarified. It is never a matter of civil war; even though of different opinions, or of different political leanings, scientists dispute each other, they compete, but they do not battle: they are bound together by a strong alliance, by the common faith "in the validity of Maxwell's or Boltzmann's equations," and by the common acceptance of Darwinism and the molecular structure of DNA.

In history and in life one sometimes seems to glimpse a ferocious law which states: to he that has, will be given; from he that has not, will be taken away.

There is Auschwitz, and so there cannot be God.

If a writer is convinced that he is honest, then it is very difficult for him to be a bad writer.

The bond between a man and his profession is similar to that which ties him to his country; it is just as complex, often ambivalent, and in general it is understood completely only when it is broken: by exile or emigration in the case of one's country, by retirement in the case of a trade or profession.

An enemy who sees the error of his ways ceases to be an enemy.

Anyone who has obeyed nature by transmitting a piece of gossip experiences the explosive relief that accompanies the satisfying of a primary need.