Iconography becomes even more revealing when processes or concepts, rather than objects, must be depicted—for the constraint of a definite thing cedes directly to the imagination. How can we draw evolution or social organization, not to mention the more mundane digestion or self-interest, without portraying more of a mental structure than a physical reality? If we wish to trace the history of ideas, iconography becomes a candid camera trained upon the scholar's mind.

"A Tale of Three Pictures", p. 428 - Eight Little Piggies (1993)