Bertrand Russell wrote in The Conquest of Happiness: “I have found, for example, that, if I have to write upon some rather difficult topic, the best plan is to think about it with very great intensity — the greatest intensity of which I am capable — for a few hours or days, and at the end of that time give orders, so to speak, that the work is to proceed underground. After some months, I return consciously to the topic and find that the work has been done.”
