“I don’t have ideas.  To begin with, nothing forces itself on me.”
“But if there’s no beginning, how do you follow it up? What do you write down first of all?”
“A note at random, then a second one and, sometimes, a third.  I then see what results.  I get by contrasting, combining and separating them.  From these various experiments there are always conclusions to be drawn; I explore the contents and developments of these.  These half-formed ideas are built up automatically; I then range and order them like a mason building a wall.  As you see, there’s nothing mysterious or secret in all this.”