"Render to me some corporal sign"--unless, of course, you are a doctor

In contrast to many of the plays we’ve seen in class, Cymbeline features characters who accept “truth” based on physical evidence (authentic or, in Iachimo’s case, crafted) rather than mere hearsay. In 5.4.364-7, Cymbeline fully accepts that his sons have returned due to the presence of a mole on Guiderius’s neck; Posthumous, in 2.4, remains convinced of Innogen’s loyalty until Iachimo presents the bracelet from her arm (Posthumous: “…’tis true – I am sure / She would not lose it.” 123-4). Even Jupiter’s message of truth comes in written form on a tablet. This value on “hard evidence” is reinforced by Innogen’s words of wisdom in 4.2.34: “Experience, O, thou disprov’st report!” With this emphasis in mind, I was shocked to see how quickly and easily Cymbeline (and others) took the doctor’s words for truth in 5.4. Cornelius arrives with a remarkable report of the Queen’s hidden feelings about everyone and everything—Cymbeline immediately accepts each revelation and asks for more. This is not the first presentation of Cornelius as all-knowing; he understands the Queen’s true nature as early as 1.5, and because of this knowledge, he is ultimately responsible for preventing Innogen’s death through poison. Why does Cornelius—a particularly marginal character in terms of stage appearance—hold so much power? What can we understand about sources of knowledge and truth in the play?