 Socrates returns to his analogy between poetry and painting. If you are partly taken in by a painting’s tricked-up table apparition but you partly spot the falseness, which part of you does which? The soul’s rational impulse must be the part that knows the painting is not a real table. But Book 4 established a fundamental principle: When the soul inclines in more than one direction, this conflict represents the work of more than one faculty or part of the soul (436b; recalled in Book 10’s argument at 602e). So being taken in by an optical or artistic illusion must be the activity of some part of the soul distinct from reason.