1. A similar point has been made by Vincent Tomas in his article “Creativity in Art,” reprinted in V. Tomas, ed., Creativity in the Arts (Englewood Cliffs: Prentice-Hall, 1964), pp. 97–109.
2. From a letter, reprinted in P.E. Vernon, ed., Creativity (Harmondsworth: Penguin, 1970), p. 55. Italics are in the original.
3. From a letter, reprinted in P.E. Vernon, ed., p. 57.
4. Quoted in R.S. Woolworth, Experimental Psychology (New York: Holt, 1938).
5. Quoted in Jacques Hadamard, The Psychology of Invention in the Mathematical Field (Princeton: Princeton University Press, 1949), p. 15.