Married life had taught Toran the futility of arguing with a female in a dark-brown mood.

Feminine intuition? Is that what you wanted the robot for? You men. Faced with a woman reaching a correct conclusion and unable to accept the fact that she is your equal or superior in intelligence, you invent something called feminine intuition.

If my doctor told me I had only six minutes to live, I wouldn't brood. I'd type a little faster.

Experimentation is the least arrogant method of gaining knowledge. The experimenter humbly asks a question of nature.

There are no happy endings in history, only crisis points that pass.

Robots will neither be common nor very good in 2014, but they will be in existence.

The Three Theorems of Psychohistorical Quantitivity: The population under scrutiny is oblivious to the existence of the science of Psychohistory. The time periods dealt with are in the region of 3 generations. The population must be in the billions (±75 billions) for a statistical probability to have a psychohistorical validity.